Posted on by Nicholos Wethington

Telescope’s Laser Pointer Clarifies Blurry Skies

The new laser adaptive optics system in action. At Mount Hopkins in Arizona, a bundle of five lasers is shot into the atmosphere to improve the imaging of the 6.3-meter MMT telescope. Image Credit: Thomas Stalcup

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While it’s handy for us humans (and all of the other life on our planet for that matter), the atmosphere is almost universally cursed among astronomers. It’s great for breathing, but when it comes to astronomical observations of faint objects, all the atmosphere tends to do is muck up the view. In the past 20 years, development of adaptive optics – essentially telescopes that change the shape of their mirrors to improve their imaging capability – has dramatically improved what we can see in space from the Earth.

With a new technique involving lasers (Yes! Lasers!), the images capable with an adaptive optics telescope could be nearly as crisp as those from the Hubble Space Telescope over a wide field of view. A team of University of Arizona astronomers led by Michael Hart has developed a technique that helps calibrate the surface of the telescope very precisely, which leads to very, very clear images of objects that would normally be very blurry.

Laser adaptive optics in telescopes are a relatively new development in getting better image quality out of ground-based telescopes. While it’s nice to be able to use space-based telescopes like the Hubble and the forthcoming James Webb Space Telescope, they are certainly expensive to launch and maintain. On top of that, there are a lot of astronomers competing for very little time on these telescopes. Telescopes like the Very Large Telescope in Chile, and the Keck Telescope in Hawaii both already use laser adaptive optics to improve imaging.

Initially, adaptive optics focused in on a brighter star near the area of the sky that the telescope was observing, and actuators in the back of the mirror were moved very rapidly by a computer to cancel out atmospheric distortions. This system is limited, however, to areas of the sky that contain such an object.

Laser adaptive optics are more flexible in their usability – the technique involves using a single laser to excite molecules in the atmosphere to glow, and then using this as a “guide star” to calibrate the mirror to correct for distortions caused by turbulence in the atmosphere. A computer analyzes the incoming light from the artificial guide star, and can determine just how the atmosphere is behaving, changing the surface of the mirror to compensate.

In using a single laser, the adaptive optics can only compensate for turbulence in a very limited field of view. The new technique, pioneered at the 6.5-m MMT telescope in Arizona, uses not just one laser but five green lasers to produce five separate guide stars over a wider field of view, 2 arc minutes. The angular resolution is less than that of the single laser variety – for comparison, the Keck or VLT can produce images with a 30-60 milli-arcsecond resolution, but being able to see better over a wider field of view has many advantages.

In the image on the left, the cluster M3 appears blurry with the laser adaptive optics system turned off. Things are much clearer using the system, and individual stars in the cluster become visible, as can be seen in the image on the right. Image Credit: Michael Hart

The ability to take the spectra of older galaxies, which are very faint, is possible using this technique. By taking their spectra, scientists are better able to understand the composition and structure of objects in space. Using the new technique, taking the spectra of galaxies that are 10 billion years old – and thus have a very high red shift – should be possible from the ground.

Supermassive clusters of stars would also be more easily scrutinized using the technique, as images taken in a single pointing of the telescope on different nights would allow astronomers to understand just which stars are part of the cluster and which are not gravitationally bound.

The results of the team’s efforts was published in the Astrophysical Journal in 2009, and the original paper is available here on Arxiv.

Source: Eurekalert, Arxiv paper

Posted on by Nancy Atkinson

Antarctic Observatory Finds Weird Pattern of Cosmic Rays

Cosmic Rays
Artists impression of cosmic rays. Credit: NASA
This "skymap," generated in 2009 from data collected by the IceCube Neutrino Observatory, shows the relative intensity of cosmic rays directed toward the Earth’s Southern Hemisphere. Researchers from UW-Madison and elsewhere identified an unusual pattern of cosmic rays, with an excess (warmer colors) detected in one part of the sky and a deficit (cooler colors) in another. Photo: courtesy IceCube collaboration

From a University of Wisconsin press release:

Though still under construction, the IceCube Neutrino Observatory at the South Pole is already delivering scientific results — including an early finding about a phenomenon the telescope was not even designed to study.

IceCube captures signals of notoriously elusive but scientifically fascinating subatomic particles called neutrinos. The telescope focuses on high-energy neutrinos that travel through the Earth, providing information about faraway cosmic events such as supernovas and black holes in the part of space visible from the Northern Hemisphere.
Continue reading “Antarctic Observatory Finds Weird Pattern of Cosmic Rays”

Posted on by Nancy Atkinson

Stunning New Image of Wolf-Rayet Star and the Carina Nebula

The Carina Nebula around the Wolf–Rayet star WR 22. Credit: ESO

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Massive stars live fast and die young. But they are also beautiful. This amazingly spectacular new image from ESO shows the brilliant and unusual star Wolf-Rayet 22 nestled within billowing, colorful folds of the Carina Nebula. WR 22 is one of many exceptionally hot and brilliant stars contained by the beautiful Carina Nebula (also known as NGC 3372), a huge region of star formation in the southern Milky Way. The image was captured by ESO’s Wide Field Imager at the La Silla Observatory in Chile.

Wolf–Rayet stars are named after the two French astronomers who first identified them in the mid-nineteenth century, and WR 22 is one of the most massive ones we know of. It is a member of a double star system and has been measured to have a mass at least 70 times that of the Sun. Although the star lies over 5000 light-years from the Earth, it is so bright that it can just be faintly seen with the unaided eye under good conditions.

The colorful backdrop of the Carina Nebula is created by the interactions between the intense ultraviolet radiation coming from WR 22 and other hot massive stars within the nebula, and the vast gas clouds, mostly hydrogen, from which they formed. The central part of this enormous complex of gas and dust lies off the left side of this picture as can be seen in image another image on the ESO website. This area includes the famous star Eta Carinae, one of the most massive stars and unstable stars in the universe.

For more info, and larger images for downloads (need a new desktop background?) see this ESO webpage.

Posted on by Nicholos Wethington

Most Massive Star Discovered: Over 300 Suns at Birth!

Zooming in on a giant: the Tarantula Nebula in the visible light on the left, a zoomed-in image of the location of R 136 in the center panel, and the R 136 cluster in the lower right of the last panel. Image Credit:ESO/P. Crowther/C.J. Evans

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Often, writing about astronomy tends to mirror the job of those writing for the Guinness Book of World Records – just when you think a record is practically unbeatable, somebody else appears to show up the previous record-holder. This is surely the case with the stellar heavyweight (er, “heavymass”) R 136a1, which has been shown by data taken using the European Southern Observatory’s Very Large Telescope and the Hubble Space Telescope to tip the stellar scales at 265 times the mass of our Sun. What’s even more impressive is that R 136a1 has lost mass over the course of its lifetime, and likely was about 320 solar masses at birth. That deserves a “Yikes!”

R 136a1 lies in a cluster of young, massive stars with hot surface temperatures that is located inside the Tarantula Nebula. The Tarantula Nebula is nested inside the Large Magellanic Cloud, one of the Milky Way’s closest galactic neighbors, 165,000 light-years away. The cluster is called RMC 136a (or more commonly referred to as R136), and in addition to the whopper that is R 136a1, there are three other stars with masses at birth in the 150 solar mass range.

Extremely massive stars like R 136a1 were previously thought to be unable to form, posing a challenge to stellar physicists as to just how this behemoth came about. It’s possible that it formed by itself in the relatively dense gas and dust of the R136 cluster, or that multiple smaller stars merged to create the larger star at some point early on in its lifetime.

If breaking the mass record weren’t enough, R136a1 also happens to be the most luminous star ever discovered, with an output of energy that is over 10 million times that of the Sun. If you want to learn more about how astronomers determine the mass and luminosity of stars, here is an excellent and thorough introduction to the subject.

To validate the models used in determining the mass and luminosity of the stars in R136, the team of astronomers led by Paul Crowther, Professor of Astrophysics at the University of Sheffield, used the VLT to examine NGC 3603, a closer stellar nursery. NGC 3603 is only 22,000 light years away, and two of the stars in that cluster are in a binary system, which allowed the team to measure their masses.

A comparison of the smallest stars (red dwarfs), Sun-like stars, blue dwarfs, and the most massive star ever discovered, R 136a1. Image Credit: ESO/M. Kornmesser

We are lucky to have observed this extremely massive star, as the rule for the most massive stars is, “Live fast, die young.” The more massive a star is, the faster it churns through the fuel that powers its increased luminosity. Our Sun, which has a medium amount of mass in relation to the two extremes, will last for around for about 10 billion years. Smaller, red dwarf stars can last trillions of years, while large stars on the scale of R 136a1 only glimmer in all of their brilliance for millions of years.

What will happen to R 136a1 at the end of its life? Stars with a mass of over 150 Suns ultimately explode in a light show of staggering proportions generated by what’s called a pair-instability supernova. For more on this phenomenon, check out this article from Universe Today from last year.

Source: ESO press release

A nod and a snarky wink to Genevieve Valentine

Posted on by Ryan Anderson

WISE Mission Completes All-sky Infrared Survey

This view of the Pleiades star cluster is a composite of hundreds of WISE images, a tiny fraction of all those collected to complete the full-sky survey. Image credit: NASA/JPL-Caltech/UCLA

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If you take a lot of digital pictures, you’re probably familiar with the frustration of keeping track of dozens of files, and always running out of hard drive space to store them. Well, the scientists and engineers on NASA’s Wide-field Infrared Survey Explorer (WISE) mission have no pity for you. Their spacecraft just finished photographing the entire sky in exquisite detail: a total of 1.3 million photos.

“The eyes of WISE have not blinked since launch,” said William Irace, the mission’s project manager at NASA’s Jet Propulsion Laboratory in Pasadena, Calif. “Both our telescope and spacecraft have performed flawlessly and have imaged every corner of our universe, just as we planned.”

WISE surveys the sky in strips as it orbits the earth. It takes six months of constant observing to map the entire sky. By pointing at every part of the sky, astronomical surveys deliver excellent data covering both well-known objects and those that have never been seen before.

“WISE is filling in the blanks on the infrared properties of everything in the universe from nearby asteroids to distant quasars,” said Peter Eisenhardt of JPL, project scientist for WISE. “But the most exciting discoveries may well be objects we haven’t yet imagined exist.”

One example of a well-known object seen in new light by WISE is the Pleiades cluster: a group of young blue stars shrouded by dust that the cluster is currently passing through. In WISE’s false-color infrared vision, the hot stars look blue but the cooler dust clouds give off longer wavelengths of infrared light, causing them to glow in shades of yellow and green.

The WISE survey is particularly significant because such a wide range of objects in the universe are visible in infrared light. Giant molecular clouds glow in infrared light, as do brown dwarfs – objects that are bigger than planets but smaller than true stars. WISE can also see ultra-bright, extremely distant galaxies whose visible light has been stretched into the infrared by the expansion of the universe during its multi-billion-year journey.

The recently completed WISE survey also observed 100,000 asteroids in our solar system, many of which had never been seen before. 90 of the newly discovered asteroids are near-earth objects, whose orbits cross our own, making them potentially dangerous but also potential targets for future mission.

You might think that 1.3 million pictures would be plenty, but WISE will keep mapping the sky for another three months, covering half of the sky again and allowing astronomers to search for changes. The mission will end when the spacecraft’s solid hydrogen coolant finally runs out and the infrared detectors warm up (they don’t work as well when they are warm enough to emit the same wavelengths of infrared light that they are meant to detect).

But even as the telescope warms up, the astronomers on the WISE team will just be getting warmed up too. With nearly two million images, they will be busy making new discoveries for years to come.

Posted on by Steve Nerlich

Astronomy Without A Telescope – Brown Dwarfs Are Magnetic Too

Brown dwarf TWA 5B compared to Jupiter and the Sun. Although brown dwarfs are similar in size to Jupiter, they are much more dense and massive - between 13 and 80 Jupiter masses. Credit: chandra.harvard.edu

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I feel a certain empathy for brown dwarfs. The first confirmed finding of one was only fifteen years ago and they remain frequently overlooked in most significant astronomical surveys. I mean OK, they can only (stifles laughter) burn deuterium but that’s something, isn’t it?

It has been suggested that a clever way of finding more brown dwarfs is in the radio spectrum. A brown dwarf with a strong magnetic field and a modicum of stellar wind should produce an electron cyclotron maser. Roughly speaking (something you can always depend on from this writer), electrons caught in a magnetic field are spun energetically in a tight circle, stimulating the emission of microwaves in a particular plane from the star’s polar regions. So you get a maser, essentially the microwave version of a laser, that would be visible on Earth – if we are in line of sight of it.

While the maser effect can probably be weakly generated by isolated brown dwarfs, it’s more likely we will detect one in binary association with a less mass-challenged star that is capable of generating a more vigorous stellar wind to interact with the brown dwarf’s magnetic field.

This maser effect is also proposed to offer a clever way of finding exoplanets. An exoplanet could easily outshine its host star in the radio spectrum if its magnetic field is powerful enough.

So far, searches for confirmed radio emissions from brown dwarfs or orbiting bodies around other stars have been unsuccessful, but this may become achievable in the near future with the steadily growing resolution of the European LOw Frequency ARray (LOFAR), which will be the best such instrument around until the Square Kilometer Array (SKA) is built – which won’t be seeing first light before at least 2017.

Geometrically-challenged aliens struggling to make a crop circle? Nope, it's a component of the LOFAR low frequency radio telescope array. Credit: www.lofar.org

But even if we can’t see brown dwarfs and exoplanets in radio yet, we can start developing profiles of likely candidates. Christensen and others have derived a magnetic scaling relationship for small scale celestial objects, which delivers predictions that fit well with observations of solar system planets and low mass main sequence stars in the K and M spectral classes (remembering the spectral class mantra Old Backyard Astronomers Feel Good Knowing Mnemonics).

Using the Christensen model, it’s thought that brown dwarfs of about 70 Jupiter masses may have magnetic fields in the order of several kilo-Gauss in their first hundred million years of life, as they burn deuterium and spin fast. However, as they age, their magnetic field is likely to weaken as deuterium burning and spin rate declines.

Brown dwarfs with declining deuterium burning (due to age or smaller starting mass) may have magnetic fields similar to giant exoplanets, anywhere from 100 Gauss up to 1 kilo-Gauss. Mind you, that’s just for young exoplanets – the magnetic fields of exoplanets also evolve over time, such that their magnetic field strength may decrease by a factor of ten over 10 billion years.

In any case, Reiners and Christensen estimate that radio light from known exoplanets within 65 light years will emit at wavelengths that can make it through Earth’s ionosphere – so with the right ground-based equipment (i.e. a completed LOFAR or a SKA) we should be able to start spotting brown dwarfs and exoplanets aplenty.

Further reading: Reiners, A. and Christensen, U.R. (2010) A magnetic field evolution scenario for brown dwarfs and giant planets.

Posted on by Tammy Plotner

Weekend SkyWatcher’s Forecast: July 16-19, 2010

Greetings, fellow SkyWatchers! Are you ready for a rock the night weekend? Then come along as you won’t need a telescope to watch the movement of the planets and the Perseid meteor shower heating up your evenings! If you’d still like a challenge, then why not chase bright asteroid Ceres with binoculars – or look up a challenging globular cluster? If you still need appeal, then there are a couple of great stars that are worth observing… and learning about! Whenever you’re ready, I’ll see you in the backyard….

July 16, 2010 – Today celebrates the 1746 birth of Giuseppe Piazzi. Although we know Piazzi best for his discovery of the asteroid Ceres, did you know he was also the first to notice that 61 Cygni had a large proper motion? Nine days and 38 years later, the man responsible for measuring 61 Cygni, Friedrich Bessel, was born.

This would indeed be a great evening to check out asteroid Ceres for yourself. You’ll find it in Ophiuchus and well placed for either binoculars or a small telescope just above the “sting” of the Scorpion! Here’s a map to help you along the way…


Now let’s take a look at gorgeous 61 Cygni. You’ll easily locate it between Deneb and Zeta on the eastern side. Look for a small trio of just visible stars and choose the westernmost (RA 21 06 54 Dec +38 44 44). Not only is it famous because of Piazzi and Bessel’s work, but it is one of the most noteworthy of double stars for a small telescope. Of the unaided visible stars, 61 is the fourth closest to Earth, with only Alpha Centauri, Sirius, and Epsilon Eridani closer. Just how close is it? Try right around 11 light-years.


Visually, the two components have a slightly orange tint, are less than a magnitude apart in brightness, and have a nice separation of around 30″ to the south-southeast. Back in 1792, Piazzi first noticed its abnormally large proper motion and dubbed it the ‘‘Flying Star.’’ At that time, it was only separated by around 10″, and the B star was to the northeast. It takes nearly seven centuries for the pair to orbit each other, but there is another curiosity here. Orbiting the A star around every 4.8 years is an unseen body that is believed to be about 8 times larger than Jupiter. A star—or a planet? With a mass considerably smaller than any known star, chances are good that when you view 61 Cygni, you’re looking toward a distant world!

July 17, 2010 – This date marks the 1904 passing of Isaac Roberts, an English astronomer who specialized in photographing nebulae. As an ironic twist, this is also the date on which a star was first photographed at Harvard Observatory!

Tonight let’s have a look at a real little powerpunch globular cluster located in northern Lupus—NGC 5824. Although it’s not an easy star hop, you’ll find it about 7 degrees southwest of Theta Librae, and exactly the same distance south of Sigma Librae (RA 15 03 58 Dec –33 04 04). Look for a 5th magnitude star in the finderscope to guide you to its position southeast.


A Class I globular cluster, you won’t find any others that are more concentrated than this. Holding a rough magnitude of 9, this little beauty has a deeply concentrated core region that is simply unresolvable. Discovered by E.E. Barnard in 1884, it enjoys its life in the outer fringes of its galactic halo about 104 thousand light-years away from Earth and contains many recently discovered variable stars.

Oddly enough, this metal-poor globular may have been formed by a merger. Research on NGC 5824’s stellar population leads us to believe that two less dense and differently aged globulars may have approached one another at a low velocity and combined to form this ultra-compact structure. Be sure to mark your observing notes on this one! It also belongs to the Bennett catalog and is part of many globular cluster lists.

July 17, 2010 – Celestial scenery alert! Are you watching the planet dance as Mars heads towards Saturn? You don’t need a telescope to enjoy the early evening trio of bright Venus along the western horizon – or the duet just above it! While you’re out enjoying a relaxing evening, keep your eyes on the skies. The early activity of the annual Perseid meteor shower is really heating up and you can expect to see several “shooting stars” an hour!


Tonight let’s begin with the 1689 birth of Samuel Molyneux. This British astronomer and his assistant were the first to measure the aberration of starlight. What star did they choose? Alpha Draconis, which oscillated with an excursion of 39’’ from its lowest declination in May. Why choose a single star during an early dark evening? Because Alpha Draconis—Thuban—is far from bright.


At magnitude 3.65, Thuban’s ‘‘alpha’’ designation must have come from a time when it, not Polaris, was the northern celestial pole star. If you’re aware that the two outer stars of the ‘‘dipper’’ point to Polaris, then use the two inner stars to point to Thuban (RA 14 04 23 Dec +64 22 33). This 300-light-year distant white giant is no longer main sequence, a rare binary type.

Now head to binary Eta Lupi, a fine double star resolvable with binoculars. You’ll find it by staring at Antares and heading due south two binocular fields to center on bright H and N Scorpii— then one binocular field southwest. Now hop 5 degrees southeast (RA 16 25 18 Dec –40 39 00) to encounter the fine open cluster NGC 6124. Discovered by Lacaille, and known as object I.8, this 5th magnitude open cluster is also Dunlop 514, Melotte 145, and Collinder 301. Situated about 19 light years away, it shows a fine, round, faint spray of stars to binoculars and is resolved into about 100 stellar members to larger telescopes. AlthoughNGC6124 is low for northern observers, it’s worth the wait to try at culmination. Be sure to mark your notes because this delightful galactic cluster is also a Caldwell object and counts for a southern skies binocular award.

Until next week? Keep capturing photons!

This week’s awesome images are (in order of appearance): 61 Cygni, NGC 5824, Alpha Draconis and NGC 6124 are from Palomar Observatory, courtesy of Caltech. Maps are courtesy of “Your Sky”. We thank you so much!

Posted on by Nancy Atkinson

Big or Small, All Stars Form the Same Way

IRAS 13481-6124 (upper left is about twenty times the mass of our sun and five times its radius. It is surrounded by its pre-natal cocoon. Image credit: NASA/JPL-Caltech/ESO/Univ. of Michigan

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How do massive stars form? This has been one of the more hotly debated questions in astronomy. Do big stars form by accretion like low-mass stars or do they form through the merging of low mass protostars? Since massive stars tend to be quite far away and usually are surrounded by a shroud of dust, they are difficult to observe, said Stefan Kraus from the University of Michigan. But Kraus and his team have obtained the first image of a dusty disc closely encircling a massive baby star, providing direct evidence that, big or small, all stars form the same way.

“Our observations show a disc surrounding an embryonic young, massive star, which is now fully formed,” said Kraus. “It’s the first time something like this has been observed, and the disk very much resembles what we see around young stars that are much smaller, except everything is scaled up and more massive.”

Not only that, but Kraus and his team found hints at a potential planet-forming region around the nascent star.

Using ESO’s Very Large Telescope Interferometer Kraus and his team focused on IRAS 13481-6124, a star located about 10,000 light-years away in the constellation Centaurus, and about 20 times more massive than our sun. “We were able to get a very sharp view into the innermost regions around this star by combining the light of separate telescopes,” Kraus said, “basically mimicking the resolving power of a telescope with an incredible 85-meter (280-foot) mirror.”

Kraus added that the resulting resolution is about 2.4 milliarcseconds, which is equivalent to picking out the head of a screw on the International Space Station from Earth, or more than ten times the resolution possible with current visible-light telescopes in space.

They also made complementary observations with the 3.58-meter New Technology Telescope at La Silla. The team chose this region by looking at archived images from the Spitzer Space Telescope as well as from observations done with the APEX 12-meter submillimeter telescope, where they discovered the presence of a jet.

“Such jets are commonly observed around young low-mass stars and generally indicate the presence of a disc,” says Kraus.

Astronomers have obtained the first clear look at a dusty disk closely encircling a massive baby star, providing direct evidence that massive stars do form in the same way as their smaller brethren -- and closing an enduring debate. This artist's concept shows what such a massive disk might look like. Image credit: ESO/L. Calçada

From their observations, the team believes the system is about 60,000 years old, and that the star has reached its final mass. Because of the intense light of the star — 30,000 times more luminous than our Sun — the disc will soon start to evaporate. The disc extends to about 130 times the Earth–Sun distance — or 130 astronomical units (AU) — and has a mass similar to that of the star, roughly twenty times the Sun. In addition, the inner parts of the disc are shown to be devoid of dust, which could mean that planets are forming around the star.

“In the future, we might be able to see gaps in this and other dust disks created by orbiting planets, although it is unlikely that such bodies could survive for long,” Kraus said. “A planet around such a massive star would be destroyed by the strong stellar winds and intense radiation as soon as the protective disk material is gone, which leaves little chance for the development of solar systems like our own.”

Kraus looks forward to observations with the Atacama Large Millimeter/submillimeter Array (ALMA), currently under construction in Chile, which may be able to resolve the disks to an even sharper resolution.

Previously, Spitzer detected dusty disks of planetary debris around more mature massive stars, which supports the idea that planets may form even in these extreme environments. (Read about that research here.) .

Sources: ESO, JPL

Posted on by Nancy Atkinson

Dying Star or Beautiful Bird?

Hubble image of IRAS 19475+3119. Credit: ESA/Hubble and NASA.

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What a gorgeous new Hubble image! At first glance this object looks like a beautiful, giant, translucent bird. But it is actually star shedding its outer atmosphere. The cloud around this bright star is called IRAS 19475+3119. It lies in the constellation of Cygnus (the Swan) about 15, 000 light-years from Earth in the plane of our Milky Way galaxy.

From the ESA Hubble website:

As stars similar to the Sun age they swell into red giant stars and when this phase ends they start to shed their atmospheres into space. The surroundings become rich in dust and the star is still relatively cool. At this point the cloud shines by reflecting the brilliant light of the central star and the warm dust gives off lots of infrared radiation. It was this infrared radiation that was detected by the IRAS satellite in 1983 and brought the object to the attention of astronomers. Jets from the star may create strange hollow lobes, and in the case of IRAS 19475+3119 two such features appear at different angles. These curious objects are rare and short-lived.

As the star continues to shed material the hotter core is gradually revealed. The intense ultraviolet radiation causes the surrounding gas to glow brilliantly and a planetary nebula is born. The objects that come before planetary nebulae, such as IRAS 19475+3119, are known as preplanetary nebulae, or protoplanetary nebulae. They have nothing to do with planets — the name planetary nebula arose as they looked rather like the outer planets Uranus and Neptune when seen through small telescopes.

This image was created from images taken using the High Resolution Channel of the Hubble Space Telescope’s Advanced Camera for Surveys. The red light was captured through a filter letting through yellow and red light (F606W) and the blue was recorded through a standard blue filter (F435W). The green layer of the image was created by combining the blue and red images. The total exposure times were 24 s and 245 s for red and blue respectively. The field of view is about twenty arcseconds across.

Source: ESA Hubble

Posted on by Tammy Plotner

Bright Outburst of QZ Virginis In Progress…


According to AAVSO Special Notice #212: “Hiroshi Matsuyama (MTH), Kanimbla, Queensland, Australia, reports and Rod Stubbings (SRX), Tetoora Road, Victoria, Australia, confirms that the SU UMa-type dwarf nova QZ Vir (formerly called T Leo) is in outburst, and possibly in superoutburst.”

Matsuyama reported it at visual magnitude 10.4 on July 9.409 UT (JD 2455386.909), and Stubbings at visual magnitude 10.0 on July 11.384 (JD 2455388.884).

According to observations in the AAVSO International Database, the last regular outburst of QZ Vir, which is 16th magnitude at quiescence, occurred 4 July 2009 (JD 2455017, magnitude 10.6, Matsuyama), when it reached visual magnitude 10.3 and faded to 15th magnitude by 9 July (2455022). The last superoutburst (see AAVSO Special Notice #144) occurred between 19 January 2009 (JD 2454851, magnitude <14.0, Stubbings) and 21 January 2009 (JD 2454853, 10.97V, R. Diethelm, Rodersdorf, Switzerland), when it reached magnitude 10.0 and returned to 16th magnitude by 1 March 2009 (2454862). If it is a superoutburst, superhumps will develop. All observations, including both visual estimates and CCD time-series photometry, are strongly encouraged at this time. Coordinates: RA 11:38:26.80 Dec +03:22:07.0 Many thanks for your valuable observing efforts and observations! This AAVSO Special Notice was prepared by Elizabeth O. Waagen.