Astronomy Archives

November 20, 2008December 24, 2015 by Nicholos Wethington

Final Resting Place of Nicolas Copernicus is Confirmed

This is what Copernicus looked like, based on forensic reconstruction from his skull. Credit: The Kronenberg Foundation

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The rightful place of the man who put the Earth in its rightful place has now been confirmed. New DNA analysis confirms that the remains of a 70-year old man found in Frombork Cathedral in Northern Poland are those of Nicolas Copernicus. Discovered three years ago, the remains allowed archaeologists produce a facial reconstruction from the skull, creating a likeness to portraits of Copernicus. But though the placement of the grave and the age of the body corresponded to the details of Copernicus’ death, scientists couldn’t be sure that the remains were actually those of Copernicus himself.

Copernicus – often known as the “father of modern astronomy” – formulated a predictive model of the Solar System that put the Sun at the center, rather than the Earth, which was believed to be the center of the Universe up until the end 16th century. He wasn’t the first to put forward the idea of heliocentrism, though; that distinction belongs to Aristarchus of the Greek island Samos, who lived in the 3rd century BC.

Copernicus, born in 1473 in Poland, used his own observations to formulate a heliocentric model of the Solar System, which he presented in his book, De Revolutionibus Orbium Coelestium (which, translated from Latin, means “On the Revolutions of Celestial Spheres”). Copernicus didn’t publish the book until 1543, the year of his death, out of fear of religious persecution. His model of the Solar System influenced Kepler to formulate his laws of planetary motion, and Galileo suffered much persecution for insisting that Copernicus was right.

The DNA analysis of two strands of hair from a book that Copernicus is known to have owned – Calendarium Romanum Magnum, by Johannes Stoeffler – match the DNA of a tooth and femur bone taken from the remains at Frombork. The book, along with a number of Copernicus’ other tomes, was taken to Sweden during the 17th century Polish-Swedish wars, and is now located at Uppsala University.

Jerzy Gasowski of the Pultusk School of Humanities in Poland was the first to find the remains in 2005, using radar to search underneath the floor of the cathedral where Copernicus was thought to have been entombed. A skull sent for forensic analysis generated the image above, but there was no DNA evidence to corroborate the find until now.

Source: BBC, Discovery

November 20, 2008December 24, 2015 by Nancy Atkinson

Astronomers Catch Binary Star Explosion Inside a Nebula

The nebula surrounding nova V458Vul before it erupted. Credit: UCL

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The explosion of a binary star inside a planetary nebula has been detected, an event not witnessed for more than 100 years – and of course the astronomical equipment to observe such an event is much improved since a century ago. At the ends of their lives, before an all-encompassing supernova explosion, some stars undergo nova explosions, caused by nuclear reactions on their surface. Astronomers who detected the event predict that the combined mass of the two stars in the system may be high enough for the stars to eventually spiral into each other, triggering a much bigger double supernova explosion.

“The star which erupted was a nova, an event caused when matter is transferred from one star in a close binary system onto its companion, eventually triggering a runaway thermonuclear explosion,” said Roger Wesson, lead astronomer behind the discovery at University College London in England.
“In August 2007, one such exploding star was discovered in a part of the sky that had serendipitously been observed by us only a few weeks previously,” he said.

Images taken prior to the explosion (above) showed that this particular star was surrounded by a planetary nebula.

The photos were taken as part of the Isaac Newton Telescope Photometric HAlpha Survey (IPHAS), which is the first digital survey of the Milky Way in visible light and is being undertaken by an international collaboration of universities.

Now, the light flash from the explosion is passing through and illuminating the surrounding nebula, the study says.

The nebula surrounding Nova V458 Vul, imaged before its central star erupted Three images showing the changes in the nebula as a result of the nova explosion, in August 2007, May 2008 and September 2008. Credit: UCL

Although several novae are discovered each year in our galaxy, only one previous nova has been seen to occur inside a planetary nebula – Nova Persei in 1901. The opportunity to watch in detail as the nova flash interacts with the nebula is a first in astronomy, said Wesson.

“The new nova, known as V458 Vulpeculae, provides an important test for models of how stars evolve,” he added. “The role of novae as potential future supernovae has thus far been difficult to analyse in detail, and so [this phenomenon] provides an opportunity to learn more about this aspect of stellar evolution.”

Source: University College of London

November 19, 2008December 24, 2015 by Nancy Atkinson

Cosmic Rays from Mysterious Source Bombarding Earth

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Scientists have discovered an unidentified source of high-energy cosmic rays bombarding Earth from space. They say it must be close to the solar system and it could be made of dark matter. “This is a big discovery,” says John Wefel of Louisiana State University and Principal Investigator for ATIC, Advanced Thin Ionization Calorimeter, a NASA funded balloon-borne instrument high over Antarctica. “It’s the first time we’ve seen a discrete source of accelerated cosmic rays standing out from the general galactic background.”

The new results show an unexpected surplus of cosmic ray electrons at very high energy — 300-800 billion electron volts — that must come from a previously unidentified source or from the annihilation of very exotic theoretical particles used to explain dark matter.

“This electron excess cannot be explained by the standard model of cosmic ray origin,” said Wefel. “There must be another source relatively near us that is producing these additional particles.”

According to the research, this source would need to be within about 3,000 light years of the sun. It could be an exotic object such as a pulsar, mini-quasar, supernova remnant or an intermediate mass black hole.

“Cosmic ray electrons lose energy during their journey through the galaxy,” said Jim Adams, ATIC research lead at NASA’s Marshall Space Flight Center in Huntsville, Ala. “These losses increase with the energy of the electrons. At the energies measured by our instrument, these energy losses suppress the flow of particles from distant sources, which helps nearby sources stand out.”

The scientists point out, however, that there are few such objects close to our solar system.

“These results may be the first indication of a very interesting object near our solar system waiting to be studied by other instruments,” Wefel said.

ATIC high-energy electron counts. Credit: J. Chang et al.

An alternative explanation is that the surplus of high energy electrons might result from the annihilation of very exotic particles put forward to explain dark matter. In recent decades, scientists have learned that the kind of material making up the universe around us only accounts for about five percent of its mass composition. Close to 70 percent of the universe is composed of dark energy (so called because its nature is unknown). The remaining 25 percent of the mass acts gravitationally just like regular matter, but does little else, so it is normally not visible.

The nature of dark matter is not understood, but several theories that describe how gravity works at very small, quantum distances predict exotic particles that could be good dark matter candidates.

“The annihilation of these exotic particles with each other would produce normal particles such as electrons, positrons, protons and antiprotons that can be observed by scientists,” said Eun-Suk Seo, ATIC lead at the University of Maryland, College Park.

The 4,300-pound ATIC experiment is carried to an altitude of about 124,000 feet above Antarctica using a helium-filled balloon about as large as the interior of the New Orleans Superdome. The goal of the project is to study cosmic rays that otherwise would be absorbed into the atmosphere.

Researchers from ATIC published the results in the Nov. 20 issue of the journal Nature.

Sources: NASA, Science@NASA

November 18, 2008December 24, 2015 by Tammy Plotner

Lepus

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Created as one of Ptolemy’s original 48 constellations and positioned just south of the celestial equator, Lepus has endured the test of time to become one of the 88 modern constellation recognized by the IAU. Spanning 290 square degrees of sky, it ranks fifty-first in size and contains only 2 bright stars, yet has 8 stars in its major asterism. Within the confines of Lepus you will also find 20 stars with Bayer/Flamsteed designations. It is bordered by the constellations of Orion, Monoceros, Canis Major, Columba, Caelum and Eridanus. Lepus is visible to all observers at latitudes between +63° and ?90° and is best seen at culmination during the month of January.

In mythology, or perhaps more correctly story and legend, Lepus represents the hare at Orion the Hunter’s feet. It is believed the winged messenger god, Hermes honored the hare for its speed, giving it a place amongst the stars. It is also believed that Canis Major, Orion’s dog, forever pursues Lepus across the sky. The Egyptians saw this constellation as associated with Osiris and fertility… Of course, there is no more fertile creature than a rabbit!

Let’s start our binocular tour of Lepus with Alpha Leporis – the “a” symbol on our map. Its name is Arneb and it literally means “hare” in Arabic. Arneb is an older, dying star that may have already passed through a supergiant phase and is now contracting and heating up in the latter phases of stellar evolution, or perhaps is still expanding into the supergiant phase. With a mass of likely less than 10 times that of the Sun, it will likely end its life as a hot white dwarf, although if it is at the heavier end of its estimated mass it may end in a spectacular stellar explosion known as a supernova. Positioned about 1300 light years from Earth, Arneb may be dying… But it still has a few years of light left for you to enjoy!

Stay with binoculars and head south for Beta Leporis – the “B” symbol on our map. Beta’s proper name is Nihal – the “drinking camel”. Somewhat similar to our Sun, this unusual 159 light year distant dwarf star outshines Sol by 165 times. Why? Probably because it’s 16 times larger. Inside it has a rapidly evolving helium core and in less than a million years it will brighten as it begins to fuse its internal helium into carbon. Now take a look in a telescope. That’s right, Nihal is a binary star. About 2.5 seconds of arc away you’ll find a companion star that’s sometimes as bright as stellar magnitude 7 and sometimes as dim as 11. So what’s going on here? Chances are the companion star is an eclipsing double, much like an Algol-type. What’s more, the primary star – Nihal A – is also a bright X-ray source, which means it has strong stellar magnetic properties. According to research, it has a high content of yttrium and the rare earths praseodymium, neodymium, and samarium – chemicals that occurred because it began life just a little hotter than usual!

Now hop to Gamma Leporis – the “Y” shape on our chart. Gamma is a multiple star system which is about 29 light-years from Earth and consists of 2 or possibly 3 stars. What’s so cool about another multiple system? This one is on the move! Gamma is part of the Sirius Moving Group Of Stars. These stars are all about the same distance away and part of a larger collective of stars known as the Ursa Major Moving Group. Based upon its stellar characteristics and distance from Earth, Gamma Leporis, a main-sequence white-yellow dwarf star, is considered a high-priority target for NASA’s Terrestrial Planet Finder mission as well!

Point your binoculars or telescope at R Leporis – better known as “Hind’s Crimson Star”. Very few places in the sky will you find such ruby beauty! This well-known variable star is right on the border of Eridanus, but since the border doesn’t show on the sky, simply use bright Rigel to help you locate it. Named after famous British astronomer J.R. Hind, who observed it in 1845, you’ll find the most excellent carbon star varies from around magnitude 5 to 12 in about 427 to 432 days. In other words, you basically observe it from one year to the next! Hind’s Crimson star is the most beautiful when it is a minima, displaying an incredible smoky red color, which turns almost garnet as it brightens the following year. Enjoy this annual favorite!

Now keep those binoculars and telescopes handy as we drop a little less than four degrees south/southwest (a binocular field) of Beta and go for Messier 79 (RA 05:24.5 Dec -24:33). This 7th magnitude globular cluster was originally discovered by Pierre Mechain and later added to the Messier Catalog. Located about 40,000 light years from our solar system, the huge ball of stars spread across 118 light years of space an incorporates tens of thousands of distant suns. What’s unusual about it? Chances are, M79 is an import to our Milky Way Galaxy. From what we can tell through recent studies, this globular cluster may have actually belonged the the Canis Major dwarf galaxy at one time and became part of our galaxy through a galaxy collision! For double star fans, look another half degree southwest where you’ll see fifth magnitude ADS 3954 and its seventh magnitude companion. A nice same field bonus!

Sources: SEDS, Wikipedia
Chart Courtesy of Your Sky.

November 18, 2008December 24, 2015 by Tammy Plotner

Leo Minor

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Leo Minor is a very small and dim constellation which was created by Johannes Hevelius in 1687 and later recognized as one of the 88 modern constellations. While Leo Minor did not belong to any older star catalogs such as those drawn up by Ptolemy in the 2nd century AD, this set of stars became part of the Firmamentum Sobiescianum, a 56 sheet atlas created by master astronomer Hevelius in an attempt to update star catalogs using what (was then) considered modern equipment. Leo Minor was one of seven new constellations and endured to become officially recognized by the International Astronomical Union. It possesses no bright stars and has only 2 main stars in its asterism, yet there are 34 Bayer/Flamsteed designated stars within Leo Minor’s confines. It spans 232 square degrees of sky and is bordered by the constellations of Ursa Major, Lynx, Cancer and Leo. Leo Minor is visible to all observers at latitudes between +90° and ?45° and is best seen at culmination during the month of April.

Since Leo Minor, the “Little Lion” is consider a new constellation, it has no ancient mythology associated with it. As you may have noticed by looking at the chart, it curiously has no Alpha star. When it came to making charts, Hevelius was great – but he didn’t label stars. It wasn’t until the 19th-century when English astronomer Francis Baily had a go at Leo Minor that he assigned the stars with their Greek letters and he simply overlooked the Alpha designation! Leo Minor is just another example of how constellation names and figures can sometimes repeat themselves, like Ursa Major and Minor, Canis Major and Minor, Pegasus and Equuleus… Hydra and Hydrus. Half the challenge to this constellation is simply finding it!

Break out your binoculars and let’s have a look at Beta Leonis Minoris – the “B” shape on our map.. This is a very rapid binary star – not in terms of movement through space – but in orbit of its companion star. Believe it or not, the 6th magnitude companion completes a full orbit in less than 40 years. That’s just a little bit slower than Saturn takes to orbit our Sun and over twice as fast at it takes Neptune!

Now head east for 46 Beta Leonis Minoris. By all rights, this should have been the Alpha star and it’s the only Bayer/Flamsteed numbered stellar designation to have a proper name – Praecipua. As stars go? Well, Praecipua is actually pretty ordinary. Just another orange giant star hanging out in space around 98 light years from Earth. It is happily radiating away about 32 times brighter than our Sun and it is around 9 times bigger. One of the coolest things about this star is just how well we know it! According to Jim Kaler’s excellent information; “Recent accurate measures of angular diameter by the Navy Interferometer show it to be 0.00254 seconds of arc across (the separation of car headlights seen from a distance of 80,000 kilometers, 20 percent of the way to the Moon), which gives it a physical diameter 8.2 times that of the Sun, the agreement with the previously calculated diameter showing that we know the size, temperature, luminosity, and distance very well.”

Now, get out your telescope and let’s go on a galaxy hunt. Our first target is NGC 3486 (RA 11:00.4 Dec +28:58). At magnitude 10, this barred spiral galaxy discovered by Sir William Herschel is around 33 million light years away and it has attitude. Even in a small telescope, observers will note a bright, sharp nucleus and larger instruments will reveal a strong central bar and patchy structure that is the signature of a Seyfert galaxy.

Next up is a large telescope challenge – NGC 3344 (RA 10:43.31 Dec +24:55). Located much closer to the Milky Way Galaxy at 25 million light years in distance, this 13th magnitude grand design spiral galaxy is a face-on presentation, and only about half the size of our own galactic home. Like our preceding observation, it, too, has a central bar – but don’t be fooled by the foreground stars! According to studies done by Verdes-Montenegro (et al), the bar is exponential and dominates the central parts, while the bulge component is small. This makes this faint customer belong to the classification of a “ringed galaxy”.

Sources: SEDS, Wikipedia
Chart Courtesy of Your Sky.

November 17, 2008December 24, 2015 by Tammy Plotner

Leo

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Positioned directly on the ecliptic plane, Leo is a constellation of the zodiac preceded by Cancer to the west and followed by Virgo to the east. It is an ancient constellation, originally charted by Ptolemy and recognized by the International Astronomical Union as one of the 88 modern constellations. Leo spans 947 square degrees of sky and is the twelfth largest of all. It contains 3 bright stars and around 15 stars in its asterism, with 92 Bayer/Flamsteed designated stars within its confines. It is bordered by the constellations of Ursa Major, Leo Minor, Lynx, Cancer, Hydra, Sextans, Crater, Virgo and Coma Berenices. Leo is visible to all observers located at latitudes between +90° and ?65° and is best seen at culmination during the month of April.

There are five annual meteor showers associated with constellation Leo. The first is the Delta Leonid meteor stream which begins becoming active between February 5 through March 19 every year. The activity peaks in late February with no exact date, and the maximum amount of activity averages around 5 meteor per hour. The next date is April 17 and the Sigma Leonid meteor shower. Look for this rare occurrence to happen near the Leo/Virgo border. It is a very weak shower and activity rates no higher than 1 to 2 meteors per hour. The next is the most dependable shower of all – the November Leonids. The peak date is November 17th, but activity occurs around 2 days on either side of the date. The radiant is near Regulus and this is the most spectacular of modern showers. The year 1966 saw 500,000 per hour a rate of up 140 per second! Just a few years ago, in 2005 the rates were equally impressive. Why? Comet Temple-Tuttle is the answer. Whenever it nears perihelion, it adds fresh material to the stream and gives us a spectacular show. On the average, you can expect around 20 per hour between 33 year shows, but they are the fastest known at 71 kps. The last is the Leo Minorids which peak on or about December 14. This meteor shower was discovered by amateurs in 1971 and hasn’t really been confirmed yet, but do look for around 10 faint meteors per hour.

In Greek mythology, Leo was identified as the Nemean Lion, which may have been the source of the “tail” of the lion that killed Hercules during one of his twelve labors. While many constellations are difficult to visualize, Leo’s backwards question-mark is relatively easily to picture as a majestic lion set in stars. One of the reasons for its placement in the zodiac is possibly due to the fact that lions left their place in the desert for the banks of the Nile when the Sun was positioned in these stars. It is also possible that the Nile’s rise at this time and the lion’s migration is also the reason for the Sphinx to appear as it does – a leonine figure. The Persians called it Ser or Shir; the Turks, Artan; the Syrians, Aryo; the Jewish, Arye; the Indians, “Sher”; and the Babylonians, Aru — all meaning a lion. Early Hindu astronomers recognized it by regal names, as did other cultures. All befitting of the “King of Beasts”!

Let’s begin our tour by taking a look at the brightest star – Alpha Leonis – the “a” symbol on our map. Its name is Regulus and it is one hot customer when it comes to spin rate. Revolving completely on its axis in a little less than 16 hours, oblate Regulus would fly apart if it were moving any faster. Ranking as the twenty-first brightest star in the night sky, Alpha Leonis is a helium type star about 5 times larger and 160 times brighter than our own Sun. Speeding away from us at 3.7 kilometers per second, Regulus isn’t alone, either. The “Little King” is a multiple star system composed of a hot, bright, bluish-white star with a pair of small, faint companions easily seen in small telescopes. The companion is itself a double at around magnitude 13 and is a dwarf of an uncertain type. There is also a 13th magnitude fourth star in this grouping, but it is believed that it is not associated with Regulus since the “Little King” is moving toward it and will be about 14″ away in 785 years. Not bad for a star that’s been reigning the skies for around for a few million years!

Let’s fade east now, and take a look at Beta Leonis – the “B” symbol on our map. Its name is Denebola which means the “Lion’s tail” in Arabic. Located about 36 light years from Earth, this white class A dwarf star is more luminous than the Sun, emitting 12 times the solar energy and a Delta-Scuti type variable star. While that in itself isn’t particularly rare, what makes Denebola unusual is that it belongs to the Vega-class stars – ones that have a shroud of infra-red emitting dust around them. This could mean a possibility of planet forming capabilities! In binoculars, look for an optical double star companion to Beta. It’s not gravitationally, or physically related, but it’s a pleasing pairing.

Now, return to Regulus and hop up for Eta Leonis, the “n” symbol on our map. Eta is very special because of its huge distance – about 2100 light years from our solar system – and that’s only a guess. It is a supergiant star, and one that is losing its stellar mass at a huge rate. Compared to Sol, Eta loses 100,000 times more mass each year! Because of its position near the ecliptic plane, Eta is also frequently occulted by the Moon. Thanks to alert observers, that’s how we learned that Eta is also a very close binary star, too – with a companion only about 40% dimmer than the primary. Some time over the next 17 million years, the pair of red supergiant stars will probably merge to become a pair of massive white dwarf stars… or they may just blow up. Only time will tell…

Hop north for Gamma Leonis – the “Y” symbol on our map. Its name is Algeiba and it is a very fine double visual star for binoculars and and true binary star small telescopes. Just take a look at this magnificent orange red and and yellow pair under magnification and you’ll return again and again. The brighter primary star is a giant K type and orbiting out about four times the distance of Pluto is its giant G type companion. Further north you’ll find another excellent visual double star for binoculars – Zeta Leonis. It’s name is Aldhafera and this stellar spectral class F star is about 260 light years away.

Are you ready to try your hand at locating a pair of galaxies with binoculars? Then let’s try the “Leo Trio” – M65, M66 and NGC 3623. Return towards Beta and look for the triangular area that marks the asterism of Leo’s “hips”. If the night is suitable for binocular galaxy hunting, you will clearly see fifth magnitude Iota Leonis south of Theta. Aim your binoculars between them. Depending on the field of view size of your binoculars, a trio of galaxies will be visible in about one third to one fourth of the area you see. Don’t expect them to walk right out, but don’t sell your binoculars short, either. The M65 and M66 pair have higher surface brightness and sufficient size to be noticed as two opposing faint smudges. NGC 3623 is spot on the same magnitude, but is edge on in presentation instead of face-on. This makes it a lot harder to spot, but chances are very good your averted vision will pick it up while studying the M65/66 pair. The “Leo Trio” makes for a fine challenge!

Now let’s begin working with larger binoculars and small telescopes as we head for M96 galaxy group (RA 10h 46m 45.7s Dec +11 49′ 12″). Messier 96 is the brightest spiral galaxy within the M96 Group which includes Messier 95 and Messier 105 as well as at least nine other galaxies. Located about 38 million light years away, this group of galaxies with the Hubble Space Telescope and 8 Delta Cephei variable stars were found to help determine each individual galaxy’s distance. While you can’t expect to see each member in small optics, larger telescopes can hope to find elliptical galaxies NGC 3489 (11:00.3 +13:54), NGC 3412 (10:50.9 +13:25), NGC 3384 (10:48.3 +12:38) and NGC 3377 (10:47.7 +13:59), as well as barred spiral galaxy NGC 3299 (10:36.4 +12:42),

For an awesome spiral galaxy in a small telescope, don’t overlook NGC 2903 (RA 9:32.2 Dec +21:30). At a bright magnitude 9, you can often see this particular galaxy in binoculars from a dark sky site as well. Discovered by William Herschel in 1784, this beauty is often considered a missing Messier because it just so bright and conspicuous. As a matter of fact, the comet of 1760 passed it on a night Messier was watching and he didn’t even see it! For larger telescopes, look for NGC 2905 – a bright knot which is actually a star forming region in the galaxy itself with its own Herschel designation.

Before we leave, you must stop by NGC 3521 (RA 11:05.8 Dec -00:02). This 35 million light year distant spiral galaxy is often overlooked for no apparent reason – but it shouldn’t be. At a very respectable magnitude 9, you can often find this elongated gem with the bright nucleus in larger binoculars from a dark sky site and you can easily study spiral galaxy structure with a larger telescope. Look for an inclined view with patchiness in the structure that indicates great star forming regions at work. Its stellar counter rotation is being studied because it has a bar structure that we are seeing “end on”!

This doesn’t even begin to scratch the surface of what you can find on Leo’s hide. Be sure to get yourself a good star chart or sky atlas and go lion taming!

Sources: SEDS, Wikipedia
Chart Courtesy of Your Sky.

November 14, 2008December 24, 2015 by Tammy Plotner

Lacerta

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The constellation of Lacerta is unusual, because it did not belong orignally to those created by Ptolemy – but to the works of Johannes Hevelius. Lacerta was included in Firmamentum Sobiescianum, a 56 page atlas created by Hevelius, which outlined seven new constellations which survived time – and many which did not. Positioned north of the ecliptic plane, it spans 201 square degrees of sky and contains 5 main stars in its asterism and 17 Bayer/Flamsteed designated stars within its boundaries. Lacerta is bordered by the constellations of Andromeda, Cassiopeia, Cepheus, Cygnus and Pegasus. It is visible to all observers at latitudes between +90° and ?90° and is best seen at culmination during the month of December.

Since Lacerta is considered a “modern” constellation, there is no mythology associated with it – although the stellar pattern was very visible to the ancient Greeks and Romans. At the time, Native American culture was highly regarded and the Chusmash of the California region referred to this area of the sky as the “Lizard”. Perhaps Hevelius honored their many stories and their culture by adopting the Latin term for lizard – Lacerta – and placing it upon this constellation.

Although Lacerta contains no bright stars, once you pick out its dim lightning bolt pattern of stars you’re well on the way to exploring with binoculars or a telescope. A sure way to help locate it is to wait for a dark night and scan the sky between Cassiopeia and Cygnus. When you’re ready, let’s take a look at Alpha Lacertae – the “a” symbol on our map. While it is just a rather ordinary A-class star residing about 102 light years away from our solar system, Alpha is about twice the size of our Sun and shines about 27 more brightly. Take a look through a telescope and you will see that Alpha appears to have a companion, but it is only an optical double star. The 11.8 magnitude line of sight interloper is really almost 2600 more light years away!

Now hop to Beta Lacertae – the “B” symbol on our map. Located about 170 light years from Earth, Beta is a giant yellow star, similar in some ways to our own Sun, but far more massive. If you’re seeing a field of stars to the west/southwest of Beta in binoculars, you’d be correct. Positioned about 2.6 degrees away from Beta is loose open cluster NGC 7243, also known as Best 59 or Caldwell 16. It contains about 40 stars and is spread out over a very large area which makes it a nice binocular object. If you’ve got the magnification power of a telescope on it, be sure to check out the brightest star in the cluster. Its name is Struve 2890 and it’s a great double star! For a telescope viewing challenge, look about 2 degrees west/northwest of Beta for IC 1434 – another open cluster. At magnitude 10, the small compressed beauty is meant for larger optics!

For another great rich field telescope treat, aim your sights towards NGC 7209 (RA: 22h 05m 12.0s Dec.:+46 29’ 59”). At a comfortably bright magnitude 7.7, this galactic star cluster is well compressed and very rich in stars. Also known as Collinder 444 and Melotte 238, this stellar beauty has been studied photometrically for reddening and metallicity, as well as the presence of suspected binary stars. Viewable in binoculars as a dim, hazy patch and well resolved in the telescope.

For binary star fans, have a look at 8 Lacerta (RA 22h 35m 52.28s Dec.: +39d 38’ 03.6”). Here you’ll find a beautiful multiple star system that’s also on the Astronomical League 100 list. In the telescope eyepiece, look for a 5.7 magnitude primary star accompanied by a 6.5 secondary star separated by about 22″. Further away you’ll find the 7.2 magnitude C star separated by about 82″. It’s very worthy of your time and attention!

Source: Wikipedia
Chart Courtesy of Your Sky.

November 14, 2008December 24, 2015 by Tammy Plotner

Weekend SkyWatcher’s Forecast – November 14-16, 2008

Greetings, fellow SkyWatchers! Are you ready for one terrific weekend? Although the Moon will interfere, one of the year’s best meteor showers is about to happen – the Leonids. Will it be the super-storm that produced thousands of meteors as it did a few years ago? Don’t hold your breath – but chances are very good you’ll spot more than one meteor for just spending a little bit of time observing. For those who enjoy using small telescopes and binoculars, it’s time to rock with the Queen as we take a look around in Cassiopeia, too. Are you ready to rock the night? Then let’s go….

Friday, November 14, 2008 – This date in history marks the discovery of what we now refer to as a “Trans-Neptunian Object” – Sedna. In 2003 Brown, Trujillo and Rabinowitz went into the books for having observed the most distant natural solar system body to date. The rethinking of what it means to be a planet that this discovery inspired would eventually spell the end to Pluto’s reign as our ninth planet! Also on this day in 1971, Mariner 9 became the first space probe to orbit Mars. Can you still spot the faint Mars at sunset?

While Cassiopeia is in prime position for most northern observers, let’s head that way tonight for some fun studies. Starting with Delta, let’s hop to the northeast corner of our “flattened W” and identify 520 light-year distant Epsilon. For larger telescopes only, it will be a challenge to find the 12″ diameter, magnitude 13.5, planetary nebula known as I.1747 in the same field as magnitude 3.3 Epsilon!

Using both Delta and Epsilon as our “guide stars,” let’s draw an imaginary line between the pair extending from southwest to northeast, continuing it the same distance until you stop at visible Iota (RA 02 29 03 Dec +67 24 08). Now go to the eyepiece… As a quadruple system, Iota will require a telescope and a night of steady seeing to split its three visible components. Approximately 160 light-years away, this challenging system will show little or no color to smaller telescopes, but to large aperture, the primary may appear slightly yellow and the companion stars a faint blue. At high magnification, the 8.2 magnitude C star will easily break away from the 4.5 primary, 7.2″ to the east-southeast. But look closely at that primary: hugging in very close (2.3″) to the west-southwest and looking like a bump on its side is the B star!

Dropping back to the lowest of powers, place Iota at the southwest edge of the eyepiece. It’s time to study two incredibly interesting stars that should appear in the same field of view to the northeast. When both of these stars are at their maximum, they are easily the brightest stars in the field. Their names are SU (southernmost – right) and RZ (northernmost – left) Cassiopeiae, and each is unique! SU (RA 02 51 58 Dec +68 53 18) is a pulsing Cepheid variable located about 1000 light-years away, and will show a distinctive red coloration. RZ (RA 02 48 55 Dec +69 38 03) is a rapidly eclipsing binary which can change from magnitude 6.4 to magnitude 7.8 in less than two hours. Wow!

Saturday, November 15, 2008 – On this day in 1990, Phil Harrington’s first book Touring the Universe through Binoculars was released, making the author a household name in the astronomy world. Since that time, Phil has published seven additional books, given countless lectures, is a contributing author to well-known astronomy periodicals, and presents technical training at Brookhaven National Laboratory. His achievements are many, and we salute you!

Above all, today we mark a very special birthday: on this day in 1738 my personal hero William Herschel was born. Among this British astronomer and musician’s many accomplishments, Herschel was credited with the discovery of the planet Uranus in 1781; detecting the motion of the Sun in the Milky Way in 1785; finding Castor’s binary companion in 1804 – and he was the first to record infrared radiation. Herschel was well known as the discoverer of many clusters, nebulae, and galaxies. This came through his countless nights studying the sky and writing catalogs whose information we still use today. Just look at how many we’ve logged this year! Tonight let’s look toward Cassiopeia as we remember this great astronomer…

Although Herschel discovered many of the famous “400” objects in Cassiopeia just two days after his birthday in 1787, we only have a short time before the Moon rises, so let’s set our sights on the area between Delta and Epsilon and have a look at three of them: NGC 654, NGC 663 and NGC 659.

At magnitude 6.5, NGC 654 (RA 01 44 00 Dec +61 53 00) is achievable in binoculars, but shows as nothing more than a hazy spot bordered by the resolvable star HD 10494. Yet, set a telescope its way and watch this diminutive beauty resolve. It is a very young open cluster which has been extensively studied spectroscopically. Oddly enough, it did not cease production of low mass stars after the larger ones formed, and shows distinct polarization. Enclosed in a shell of interstellar matter, almost all of NGC 654’s stars have reached main sequence and two have been identified as detached binaries.

Now shift your attention to NGC 663 (RA 01 46 12 Dec +61 14 00). At magnitude 7, it is also viewable as a faint glow in binoculars – but is best in a telescope. With an age of about nine million years, this cluster contains the largest concentration of Be-type stars known: such stars show strong emission lines in hydrogen. While this might be considered “normal” for a B-type star, the mystery behind Be-types is that their emissions can simply end at any time – only to resume later. This could be in a matter of days, or it could be decades – but these odd stars may very well be victims of rapid rotation, high magnetic activity (similar to flares), or even interactions with a companion.

Time to head toward the faintest of the three – NGC 659 (RA 01 44 24 Dec +60 40 00). At magnitude 8, it is still within the reach of larger binoculars and will be fully resolved with a mid-sized telescope. Studied as recently as 2001, this looser collection contains seven newly discovered variables – three of which are Be stars. But, give credit where credit is due! For as avid as Sir William was about observing, he had an equally avid observing partner: his sister Caroline. This time it was her call, as she is credited with the discovery of this particular open cluster – four years before her brother added it to his list in 1787!

Sunday, November 16, 2008 – Today in 1974, there was a party at Arecibo, Puerto Rico, as the new surface of the giant 1000-foot radio telescope was dedicated. At this time, a quick radio message was released in the direction of the globular cluster M13.

Tonight let’s take advantage of early dark and venture further into Cassiopeia. Returning to Gamma, we will move toward the southeast and identify Delta. Also known as Ruchbah, this long-term and very slightly variable star is about 45 light-years away, but we are going to use it as our marker as we head just one degree northeast and discover M103 (RA 01 33 24 Dec +60 39 00). As the last object in the original Messier catalog, M103 (NGC 581) was actually credited to Méchain in 1781. Easily spotted in binoculars and small scopes, this rich open cluster is around magnitude 7, making it a prime study object. About 8000 light-years away and spanning approximately 15 light-years, M103 offers up superb stars in a variety of magnitudes and colors, with a notable red in the south and a pleasing yellow and blue double to the northwest.

Keep watch for shooting stars tonight, because the annual Leonid meteor shower is underway. For those of you seeking a definitive date and time, it isn’t always possible. The meteor shower itself belongs to the debris shed by comet 55/P Tempel-Tuttle as it passes our Sun in its 33.2 year orbit. Although it was once assumed it would simply be about 33 years between the heaviest “showers,” we later came to realize the debris formed a cloud which lagged behind the comet and dispersed irregularly. With each successive pass of Tempel-Tuttle, new filaments of debris are left in space along with the old ones, creating different “streams” the orbiting Earth passes through at varying times, which makes blanket predictions unreliable at best.

So if you didn’t stay up late, then get up early the next morning to catch the Leonids. Each year during November, we pass through the filaments of its debris – both old and new ones – and the chances of impacting a particular stream from any one particular year of Tempel-Tuttle’s orbit becomes a matter of mathematical estimates. We know when it passed… We know where it passed… But will we encounter it and to what degree? Traditional dates for the peak of the Leonid meteor shower occur as early as the morning of November 17 and as late as November 19, but what about this year? On November 8, 2005 the Earth passed through an ancient stream shed in 1001. Predictions ran high for viewers in Asia, but the actual event resulted in a dud. There is no doubt that we crossed through that stream, but its probability of dissipation was impossible to calculate. Debris trails left by the comet in subsequent years look promising, but we simply don’t know.

We may never know precisely where and when the Leonids might strike, but we do know that a good time to look for this activity is well before dawn on November 17, 18 and 19. With the Moon blocking the way, it will be difficult this year, but wait until the radiant constellation of Leo rises and the chances are good of spotting one of the offspring of periodic comet Tempel-Tuttle. Remember to dress warmly and provide for your viewing comfort.

Enjoy your weekend and remember… Ask for the Moon, but keep on reaching for the stars!

This week’s awesome images are: Iota, SU and RZ Cassiopeiae – Credit: Palomar Observatory, courtesy of Caltech, Sir William Herschel (widely used public image), NGC 654, NGC 653, NGC 659 and M103 – Credit: Palomar Observatory, courtesy of Caltech and Leonid Meteor Shower – Credit: NASA. We thank you so much!

November 13, 2008December 24, 2015 by Tammy Plotner

Indus

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The constellation of Indus was originally created by Petrus Plancius from the observations of Dutch sea navigators Pieter Dirkszoon Keyser and Frederick de Houtman when exploring the southern hemisphere. Indus’ stellar patterns became known when it appeared on a celestial globe in 1597 and was considered a constellation when it was added to Johann Bayer’s Uranometria catalog in 1603. It survived the years to become one of the 88 modern constellations recognized by the International Astronomical Union. Indus is located south of the ecliptic plane and covers approximately 294 square degrees of sky. It consists of three main stars in the primary asterism and has 16 stars with Bayer/Flamsteed designations. Indus is bordered by the constellations of Microscopium, Sagittarius, Telescopium, Pavo, Octans, Tucana and Grus.

Since the constellation of Indus wasn’t created until late in the sixteenth century, there isn’t any ancient mythology associated with its stellar patterns. However, Indus is meant to represent as a native – perhaps one met by the Dutch explorers on their travels in the Indies or Africa. It is also believed that Johannes Bayer wish to honor the native American Indians as well, so Indus was thus included in his works.

For observers, let us begin with binoculars the brightest star – Alpha Indi – the “a” symbol on our map. Who know exactly how stars sometimes get their names, but you’ll often find this star is called ” the Persian” on some lists. Located about 101 light years from our solar system, Alpha is super-metal-rich, K-type orange giant star that outshines our own Sun by about 62 times. Have a telescope? Be sure to take a look at “the Persian”. You’ll find it has a pair of 12th and 13th magnitude red dwarf star companions!

Now hop to the center of this Y-shaped asterism and have a look at Theta Indi. That’s right! Another binary star. Located about 91 light years from Earth, you’ll find a very nice double star here, with components that are easy to separate with a small telescopes. The primary is fifth magnitude and the secondary is magnitude seven.

Time to follow the branch of the Y southwest and have a look at Beta Indi – the “B” shape on our map. While the rest of the stars we’ve look at so far were fairly near – Beta isn’t. Located at minimum of 600 light years away, Beta Indi is a very massive and luminous star of the orange K-type classification. Take a look through the telescope, too… Because you’ll find that Beta also has a 12th magnitude visual companion whose distance is unclear. At the southeast end of the Y branch is Delta, whose orbital mechanics have been closely studied.

Now drop south for Epsilon – the backward “3”. Epsilon Indi is one of the closest stars to Earth, approximately 11.82 light years away. Epsilon is a dwarf star – only about 75% the size of our own Sun – and very similar in respects to movement, corona and gravity. Even its photosphere and metallicity is a close comparison. In 1847, Heinrich Louis d’Arrest was the first to notice that Epsilon had moved right along compared to its charted 1750 position, and it has been measured about every 100 years since. Astronomers have since placed it in what is called the Epsilon Indi Moving Group of Stars – a stellar association of about 16 members that quite likely formed about the same time in the same location.

Of course, being so close means Epsilon was also the object of many signal studies, including radio signals and lasers – but unfortunately, no signals were ever returned. Even though we haven’t gotten a reply, it still leads the list of 17,129 nearby stars most likely to have planets that could support complex life. With good reason! In January 2003, astronomers announced the discovery of a brown dwarf with a mass of 40 to 60 Jupiter masses in orbit around Epsilon Indi at a distance of at least 1500 astronomical units… And what’s more, it’s actually a binary brown dwarf star! Although measurements of the radial velocity of Epsilon Indi appear to show the presence of a planetary companion with an orbital period of more than 20 years, so far no space telescope yet has been able to prove its existence.

Now it’s time to take a telescope tour of Indus. Our first object is IC 5152 (RA 22:02.9 Dec -51:17). Hanging out about 3 million light years away, this irregular dwarf galaxy could very well be an outlying member of our own Milky Way local group of galaxies. At roughly magnitude 11, look for some patchy details, including a line of sight star caught on its edge.

Next up? NGC 7090 (RA 21:36.5 Dec -54:33). Even though billed at near magnitude 11, this soft spoken spiral galaxy is low surface brightest to the eye – but an astrophotographer’s dream. It has a fantastic h-alpha halo! Look for several scattered stars in the same field, including a very wide equal optical pair lying to the east.

Hop now to NGC 7083 (RA 21:35.7 Dec -63:54). At magnitude 12, this galaxy is meant for larger telescopes, but this barred galaxy is also highly studied for its spiral galaxy structure. It is considered a grand design and well worth taking some time on!

Last for now? NGC 7049 (RA 21:19.0 Dec -48:34). Although on the small side, NGC 7049 is a bit brighter than our last study at magnitude 11. It is an early-type spiral galaxy and also a target of the Hubble Space telescope, which studied it for its inner polar disc properties. You’ll find it about about 15′ east of a bright, yellowish star (6.5 magnitude) and the surface brightness will allow you to do a little more serious studying!

Source: Wikipedia, ESO
Chart courtesy of Your Sky.

November 12, 2008December 24, 2015 by Nancy Atkinson

Cassini Finds New Mysterious Infrared Aurora

An infrared camera aboard NASA’s Cassini spacecraft has discovered a unique aurora lighting up Saturn’s polar cap. The mysterious new aurora is unlike any other known in our solar system. “We’ve never seen an aurora like this elsewhere,” said Tom Stallard, an RCUK Academic Fellow working with Cassini data at the University of Leicester. Stallard is lead author of a paper released today (13th
November) in the journal Nature. “It’s not just a ring of aurorae like those we’ve seen at Jupiter or Earth. This one covers an enormous area across the pole. Our current ideas on what forms Saturn’s aurorae predict that this region should be empty, so finding such a bright one here is a fantastic surprise.”

Aurorae are caused when charged particles stream along the magnetic field of a planet and into its atmosphere. On Earth these charged particles come from the solar wind – a stream of particles that
emanates from the Sun.

Jupiter’s main auroral ring, caused by interactions internal to Jupiter’s magnetic environment, is constant in size. Saturn’s main aurora, which is caused by the solar wind, changes size dramatically as the wind varies. The newly observed aurora at Saturn, however, doesn’t fit into either category.

“Saturn’s unique auroral features are telling us there is something special and unforeseen about this planet’s magnetosphere and the way it interacts with the solar wind and the planet’s atmosphere,” said
Nick Achilleos, Cassini scientist on the Cassini magnetometer team at the University College London. “Trying to explain its origin will no doubt lead us to physics which uniquely operates in the environment of Saturn.”

The new infrared aurora appears in a region hidden from NASA’s Hubble Space Telescope, which has provided views of Saturn’s ultraviolet aurora. Cassini observed it when the spacecraft flew near Saturn’s polar region. In infrared light, the aurora sometimes fills the region from around 82 degrees north all the way over the pole. This new aurora is also constantly changing, even disappearing within a 45 minute-period.

Source: NASA