The Celestron “FirstScope” Telescope: Official Product of International Year of Astronomy

Celestron FirstScope Telescope

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One of the most important goals of the International Year of Astronomy is to “promote widespread access to the universal knowledge of fundamental science through the excitement of astronomy and sky-observing experiences.” What’s the objective? “Enable as many laypeople as possible, especially children, to look at the sky through a telescope and gain a basic understanding of the Universe.” And how is this going to be facilitated? By the “number of laypeople, especially young people and children, viewing the Universe through a telescope at street astronomy events, star parties, professional observatory webcasts etc.” and the “number of ‘cheap’ new telescope kits produced, assembled and distributed.” Well, the Celestron FirstScope Telescope hits the mark perfectly as aimed at anyone, able to view the Universe and inexpensive, but it’s anything but cheap…

In 1609, world-renowned Italian scientist, Galileo Galilei, introduced an elementary telescope to the growing astronomy community which sparked interest into the mysterious night sky for centuries to come. Four centuries later, in celebration of the International Year of Astronomy 2009, Celestron offers the portable FirstScope Telescope. The FirstScope pays tribute to Galileo Galilei and many of history’s most notable astronomers and scientists by displaying their names around the optical tube. We honor the contributions of these men and women, who brought us one step closer to understanding the universe around us.

When I first read the introduction and saw the first images of the Celestron Firstscope Telescope, I knew that I’d have to get my hands on one. They are a unique little altazimuth reflector – a tabletop model that bears a strong resemblance to the dobsonian design. Of course, I read the specifications, and I knew that a 76 mm (2.99 in) aperture reflector optical tube with a 300 mm (11.81 in) focal length wasn’t going to be a whole lot large than a tennis ball can, but I’ve learned that small telescopes are quite capable of performing some amazing feats when put into the right hands. According to what I’ve read the Celestron First Scope is a nice, fast focal ratio of f/3.95… and from what I know of Celestron telescopes, it should behave quite nicely. But there’s only one problem.

They aren’t available on the market yet.

So who would be the kind of person to wander around NEAF confronted with telescopes worth tens of thousands of dollars, but would be the one to take off to neverland with a kid’s telescope that cost less than $50? Yeah. You’re right. Me.

celestron-firstscope-1From the moment I laid eyes on the little black sonotube covered with the most famous names in astronomy, I was charmed. The mount is absolutely made out of enamel covered pressboard and its bearing is basically a big locking nut… But, hey. So am I. I took the whole thing apart and put it back together again (sans removing primary mirror cell, secondary and focuser – because I didn’t want to have to go “borrow” a laser collimator) in a matter of minutes and I found it surprisingly well constructed. Both the base and the bearing are going to hold up to use… And I don’t mean just casual use… I mean good, hard, honest-to-goodness kid use. Unlike a dobsonian, the side bearing needs to be loosened to move the telescope in its “up and down” path and re-tightened to hold position, but the user is faced with two options. The bearing is machined well enough that it can be placed to the “just snug” point where friction holds it in place and allows for minor movements (such as slight tracking adjustments) and it is quite strong enough to allow for thousands of tightening (and overtighenings) as the years go past. If something should strip out? These are common parts. It can be replaced with trip to the hardware store.

Now for the optical tube…

firstcopeGood old sturdy sonotube. I used to be afraid of “cardboard” many years ago, but I’ve learned with time. Despite what you might think, it holds up to dew, cools down to ambient temperature like a dream, and really has its advantages – like not dinging easily. The 1.25″ rack and pinion focuser on the Celestron FirstScope Telescope is very standard and a tiny bit stiff, but we’re not talking cotton candy here. The focuser is surprisingly quality, well-machined, and is going to withstand use and abuse. It has excellent clearance from the secondary and more than sufficient enough backfocus to allow for a wide variety of eyepieces. What’s that you say about eyepieces? Oh, yeah. Again, Celestron has outdone themselves by providing two 1.25″ eyepieces – a 20mm and a 4mm. Did I hear you groan? Yeah. Me, too. A 4mm is simply too much magnification for a scope that size, but when testing it on a larger, more stationary target (like the Moon) I found it wasn’t too bad. Again, surprising quality because the eyepieces and focuser alone were worth what the telescope cost!

How did it perform? If you aimed the Celestron FirstScope at something large, you’d be doing fine if you were a beginner, but like most small optical tube assemblies – it isn’t offered with a finderscope. While reflex sighting along the tube isn’t too hard to do, I can also see where that could be extremely frustrating for someone a bit more new to the game. So… I asked for a solution. Guess what? Celestron telescope had one that fit the criterion – inexpensive, but not cheap.

first_scope_accessoriesEnter the Celestron FirstScope Telescope Accessory Kit. People? For under $20 I just got handed a 1.25″ Celestron 12.5 mm eyepiece, 6mm eyepiece, moon filter, nifty little carry bag for the whole outfit, and get this… a 5X24 finderscope and bracket. No kidding! A real, honest-to-goodness optical finderscope… Not one of those “red dot” marvels that accidentally get left on and whose batteries run down and end up being totally useless next time you go out unless you have spares. Folks? You can’t even buy a moon filter for under $20, let alone a finderscope, eyepieces and… and… what’s this? Why, there’s even a CD ROM in here called “Sky X” that teaches you, prints maps, runs a planetarium program and more.

Am I impressed? Yes. I will give you fair warning that the Celestron FirstScope telescope is not the Hubble. I will stress to you repeatedly that you are not going to see majestic sweeping spiral arms on tiny galaxies – nor are you going to resolve globular clusters or reveal intricate planetary details. But, what you can expect from this telescope is far, far more than Galileo saw 400 years ago. When put on a steady surface, the Moon will display its tortured surface and Jupiter its moons. Bright, open star clusters will become things to marvel over and the Andromeda Galaxy will look like it truly is next door. Just as the rings of Saturn “disappeared” on Galileo so long ago, you will only see a fine line now to mark their place until the tilt changes again… But who cares when the summer skies are filled with bright nebula to explore, fuzzy globular clusters to capture and the Milky Way curls across the sky like a swarm of fireflies? Do it for your kids… Do it for your grandkids. Do it for yourself as a momento of IYA 2009. You won’t be disappointed.

It’s small wonder the Celestron FirstScope telescope named was Official Product of International Year of Astronomy 2009, for the FirstScope truly pays tribute to the men and women who brought us one step closer to understanding the Universe around us by putting an affordable “real telescope” into the hands of anyone who wants one. It won’t be long until they’re available at Celestron dealers everywhere, and you’ll find them for under $50 (and the accessory kit for under $20) at premier Celestron dealers like Oceanside Photo and Telescope, Scope City, High Point Scientific, Adorama and Astronomics.

Reminder to Universe Today Readers… Don’t forget! While all premier Celestron dealers will offer the FirstScope at the same price, you’ll get a discount for being a Universe Today reader if you enter our name in the Club Affliliation section if you chose to order a Celestron FirstScope from OPT.

Submit Your Questions for Scott Parazynski and Keith Cowing

Scott and Danru on Pumor RI with Everest Behind Them. Credit: OnOrbit.com

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Former astronaut Scott Parazynski is making an attempt to climb Mt. Everest, and has been sharing his adventures via Twitter, and his blog on OnOrbit.com. As we reported in in our article about Parazynski in March, he wants to share his experiences with as many people as possible. Earlier today, his “media sherpa,” Keith Cowing from NASA Watch.com joined Parazynski at base camp and both Cowing and Parazynski have agreed to take questions from readers of Universe Today and answer them during their time on Mt. Everest. Parazynski has been blogging and Twittering during his preparations for the climb, and he even wants to Twitter from the summit. “I want to tell the story of exploration here on Earth and the corollaries it has with space exploration,” Parazynski told Universe Today before he left for Kathmandu, Nepal. “The intent is to share the story with as many people as we can, particularly young people.”

So submit your questions in the comments section and we’ll relay them on. Questions can be about mountain climbing or space exploration.

For more information about check out Scott’s Twitter feed, and the OnOrbit blog, and you can even track Parazynski with his SPOT GPS locator system — which is kind of interesting to look at, as you can see how he has been going up and down the mountain the past couple of weeks to acclimate his body to higher elevation.

The Case of the Missing Planets: Are Stars Eating Their Young?

COROT-exo-7b, bottom left dot shadows in front of his central star (artist's impression). Because of its proximity to the star, researcher believe it will be pulled into the star and destroyed. Image: Klaudia Einhorn.

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A new era on astronomy began in 1995 when the first extrasolar planet was detected. To date, 346 planets have been found orbiting stars other than our sun. But new research indicates astronomers might have found even more extrasolar planets except for one thing: some planets have either been pulled into their parent star and devoured or gravitationally torn apart. .And astronomers say the most Earth-like planet detected so far, CoRoT-7 B will inevitably be destroyed by the star it orbits.

The idea that gravitational forces might pull a planet into its parent star have recently been predicted by computer models and Barnes and his team now have evidence that such planet destruction has already occurred.

“When we look at the observed properties of extrasolar planets, we can see that this has already happened – some extrasolar planet have already fallen into their stars,” said Rory Barnes from the University of Washington.

The computer models can show where planets should line up in a particular star system, but direct observations show that some systems are missing planets close to the stars where models say they should be.

But because the planet is so close to the star, the two bodies begin pulling on each other with increasingly strong gravitational force, misshaping the star’s surface with rising tides from its gaseous surface.

“Tides distort the shape of a star. The bigger the tidal distortion, the more quickly the tide will pull the planet in,” said lead author Brian Jackson from the Lunar and Planetary Institute.
Most of the planets discovered outside of our solar system are gas giants like Jupiter except that they are much more massive. However, earlier this year astronomers detected an extrasolar planet called CoRoT-7 B that, while significantly larger than our planet, is more like Earth than any other extrasolar planet found so far.

However, that planet orbits only about 1.5 million miles from its star, much closer than Mercury is to our sun, a distance that puts it in the category of a planet that will fall into its star. Its surface temperature is around 2,500 degrees Fahrenheit “so it’s not a pleasant environment,” Barnes said, and in a short time cosmically – a billion years or so – CoRoT-7 B will be consumed.

The destruction is slow but inevitable, Jackson said.

“The orbits of these tidally evolving planets change very slowly, over timescales of tens of millions of years,” Jackson said. “Eventually the planet’s orbit brings it close enough to the star that the star’s gravity begins tearing the planet apart.

“So either the planet will be torn apart before it ever reaches the surface of the star, or in the process of being torn apart its orbit eventually will intersect the star’s atmosphere and the heat from the star will obliterate the planet.”

The researchers hope the work leads to better understanding of how stars destroy planets and how that process might affect a planet’s orbit, Jackson said.

The scientists also say their research will have to be updated as more extrasolar planets are discovered, and the researchers are looking forward to investigating new planets found by the Kepler telescope, which is designed specifically to look for extrasolar planets that are closer in size to Earth.

Jackson hopes new observations will provide new lines of evidence to investigate how a star’s tides can destroy planets.

“For example, the rotation rates of stars tend to drop, so older stars tend to spin more slowly than younger stars,” he said. “However, if a star has recently consumed a planet, the addition of the planet’s orbital angular momentum will cause the star to rapidly increase its spin rate. So we would like to look for stars that are spinning too fast for their age.”

Read the paper on this topic.

Source: EurekAlert

Most Distant Object Ever Seen

Artists concept of a gamma ray burst. Credit: UC Berkeley

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According to the Sky and Telescope blog, NASA’s Swift satellite captured a faint gamma-ray burst (GRB) last Thursday which has smashed the record for the earliest, most distant known object in the universe. Various ground-based telescopes following up on Swift’s initial detection of the GRB have measured redshifts of the object, varying from 7.6 to 8.2. Whatever the final determination is of how much this GRB’s afterglow has been redshifted by the expansion of the Universe, it will set a record. In September 2008, Swift captured GRB 080913, the most distant gamma-ray burst ever detected, with a redshift of 6.7. Astronomers using the Very Large Telescope in Chile have determined that this current GRB (090423) went off about 600 million years after the Big Bang.

A GRB comes from the cataclysmic explosion of a massive star, which could signal the birth of a black hole, a collision of two neutron stars or some other unknown phenomenon. These bursts occur approximately once per day and are brief, but intense, flashes of gamma radiation. They come from all different directions of the sky and last from a few milliseconds to a few hundred seconds.

Since the Swift satellite was launched in 2004, it has undoubtedly seen GRBs with even higher redshifts, but many bursts have afterglows so faint that astronomers are unable to determine their redshifts. The most distant galaxies with well-measured redshifts are in the 6’s.

NASA is supposed to issue a press release with more information later today, and we’ll provide an update at that time.

Were the Dinosaurs Really Wiped Out by an Asteroid? Possibly Not (Update)

In 1979, the huge Chicxulub crater, measuring about 180 km (112 miles) in diameter, was discovered on the northern Yucatan Peninsula, Mexico. Scientists made the obvious conclusion that something rather large had hit the Earth in this location, probably causing all kinds of global devastation 65 million years ago. At around the same time, 65% of all life on the face of the planet was snuffed out of existence. The dinosaurs that roamed the planet up to that point were no more.

The timing of asteroid impact and the time of the mass extinction was too much of a coincidence to be ignored. When particles from the asteroid impact were discovered just below the Cretaceous-Tertiary (K-T) boundary, there was a strong causal link: the effects of the asteroid impact had driven the dinosaurs to extinction.

However, a problem with this theory has come to light. It turns out the Chicxulub impact may pre-date the K-T boundary by 300,000 years…

A number of scientists have disagreed with the theory that the Chicxulub impact caused the death of the dinosaurs 65 million years ago, and this newest research appears to show the two events may not be linked after all.

Gerta Keller of Princeton University in New Jersey, and Thierry Adatte of the University of Lausanne, Switzerland, are set to publish this new work in the Journal of the Geological Society today, using data from the analysis of sediment from Mexico to prove the asteroid impact pre-dated the K-T boundary by as much as 300,000 years.

We know that between four and nine meters of sediments were deposited at about two to three centimeters per thousand years after the impact,” said Keller. “The mass extinction level can be seen in the sediments above this interval.”

This means that the mass extinctions appeared to take place a long time after the impact. However, impact-extinction advocates point out that this inconsistency in sediment data is probably down to sediment disruption by tsunamis and geological upheaval immediately after the impact.

According to Keller, there is no indication that this could be the case. Deposition of impact sediment occurred over a huge time period, not the hours or days deposition would have taken if a tsunami affected sedimentary records.

Another problem with the impact extinction theory is that the Chicxulub impact may not have had the radical extinction effect on plants and animals as we previously thought. The researchers found a total of 52 fossilized species that appeared to be happily living before the layer of impact sediment… and the same 52 species appeared to by happily living after the layer of impact sediment.

We found that not a single species went extinct as a result of the Chicxulub impact.” — Gerta Keller

Although this is some very interesting research, sure to turn dinosaur extinction theory on its head, if an asteroid didn’t kill the dinosaurs, what did?

Keller points the finger at volcanic activity. Massive amounts of dust and gas was released from eruptions at the Deccan Traps in India 65 million years ago, possibly plunging the planet into a prolonged period without Sun.

Update: With any scientific debate, there are details behind new research that may not be immediately apparent. As Ethan Siegel highlights in a recent ScienceBlogs article (What Wiped Out The Dinosaurs?, April 27th), the evidence for an asteroid impact wiping out the dinosaurs is overwhelming. Just because there appears to be a discrepancy in the location of impact sediment and K-T boundary does not mean the impact-extinction theory is wrong in any way. Keller’s research is an interesting investigation, worthy of further study, but this doesn’t change the fact that huge global damage would have been caused by the Chicxulub impact. This remains the prime candidate as to why the dinosaurs were suddenly made extinct 65 million years ago.

Source: Physorg.com

Model Saturn V Rocket Launch a Success

Saturn V rocket launch. Credit: Gizmodo.com

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A world record model rocket launch attempt on Saturday lifted off — and landed — successfully. Steve Eves worked for two years building the rocket, a 36-foot (10.9-meter) tall, 1:10 scale Saturn V model rocket. Eves now holds the world record for the largest amateur rocket to ever be launched. The picture-perfect launch took place on a farmer’s field near Price, Maryland, about 50 miles (80 km) east of Baltimore, delighting those in attendance. The main body of the rocket even landed upright. See the video below.

Here’s a link to a video of Steve Eves talking about his rocket before the launch.

Thanks to Keith Stein of the DC Space News Examiner for passing the word on to us.

Did Dark Matter Annihilate Our Early Universe?

A billion years after the big bang, hydrogen atoms were mysteriously torn apart into a soup of ions.

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380,000 years after the Big Bang, the Universe cooled from being a hot soup of plasma, to a temperature where protons and electrons could combine to form atoms. This calm period of neutral hydrogen in universal history didn’t last for long however. The neutral hydrogen atoms were ripped apart once more, by a mechanism that would go on to reionize the entire Universe, a process that eventually ended a billion years after the Big Bang.

It is thought the first stars that formed prior to the reionisation epoch probably pumped out some fierce ultraviolet radiation, ionizing the neutral hydrogen, but a new (controversial) theory has been put forward. Did dark matter have a role to play in the reionisation the Universe?

As 85% of the Universe is composed of a type of matter we have yet to fully account for, it seems only natural that scientists would be looking into the possibility that dark matter had a role to play soon after the Big Bang. Although scientists are fairly confident that the reionisation period was driven by the emissions from the very first stars, there are some observational factors that could suggest dark matter annihilation might have had a role to play in the evolution of the Universe.

This is according to Dan Hooper and Alexander Belikov from Fermilab in Batavia, Illinois, in any case. In their theory recently published, the researchers examine the physics behind dark matter annihilation as the mechanism that drove the reionisation epoch.

reion_diagramIn Hooper and Belikov’s work, they focus on dark matter that is theorized to have clumped together under gravitational attraction as the Universe cooled during the neutral hydrogen era (known as the “Dark Ages” – the Universe would have been opaque due to lack of stars and lack of electromagnetic radiation). When the dark matter during this time clumped, it is predicted to annihilate. During dark matter annihilation, high energy gamma-rays are predicted to be generated. Where gamma-radiation goes, ionization of matter is sure to follow.

A single gamma ray might reionise 1000 hydrogen atoms,” says Hooper. “The mechanism could easily have reionised the universe.”

By their reasoning, rather than emissions from stars that may have been forming at the start of the reionisation epoch, a far more potent ionization mechanism could have flooded the Universe. However, some scientists are skeptical of this idea.

We have no evidence yet that any dark matter has ever annihilated,” says Charles Bennett, principal investigator on NASA’s WMAP satellite, which has been studying the reionisation epoch. “I am not saying it is wrong, but it sounds a bit too contrived for me to eagerly accept it.” Bennett sees the dark matter argument as one mystery (reionisation) being explained by another mystery (does dark matter even annihilate?).

For now, the idea that dark matter may have been the underlying mechanism ionizing our Universe remains highly theoretical. But Hooper is eager to study the data from ESA’s upcoming Planck mission as this observatory will be able to study how reionisation proceeded with time. “The time signature of dark matter reionisation will be different from that brought about by stars,” says Hooper.

Source: New Scientist

Mars Express Spies Rocky, Chaotic Terrain on Mars

Ariadnes Colles that lies at about 34° south and 172° east. The ground resolution is about 13 m/pixel. Credits: ESA/ DLR/ FU Berlin (G. Neukum) Click for larger version

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Wow – what a shot by Mars Express! Mars has several regions of what is called ‘chaotic terrain’. These are areas with large accumulations of rocks of varying sizes, as well as flat-topped features. These erratically shaped rocks are large, too: between 1-10 km in size. Some chaotic terrain on Mars is thought to form when there is a sudden removal of subsurface water or ice, causing the surface material to slump and break into blocks. The region shown here, however — Ariadnes Colles — is not a water-source region, so scientists are still debating whether Ariadnes Colles was formed by the action of water or wind. Either way, this is a very interesting region. See below for a straight on view that’s just as incredible.

This image by the Mars Express High Resolution Stereo Camera, shows the region of Ariadnes Colles on the Red Planet.     Credits: ESA/ DLR/ FU Berlin (G. Neukum)   Click for larger version
This image by the Mars Express High Resolution Stereo Camera, shows the region of Ariadnes Colles on the Red Planet. Credits: ESA/ DLR/ FU Berlin (G. Neukum) Click for larger version

A large impact crater, 1200 m deep, is visible on the right, which has a smaller crater inside of it. The larger crater is about 30 km in diameter and covers an area roughly the size of Hamburg, Germany. The smaller younger crater lies almost at the center of the older one, and has a diameter of just 10 km.

Interestingly, the blocks, or mesas have a striking lineation, as almost all are oriented in the northwest-southeast direction. By looking at the larger versions, it’s possible to see the northwestern flanks have been eroded more strongly than the opposing southeastern ones.

Some slopes of the flat-topped mesas have been covered by darker material, likely sand or volcanic ash that was blown up on the slopes.

Anyone ready to visit this interesting region?

Source: ESA

Mars Rover Spirit is Rolling Again After Memory Problems

Image taken by Spirit of a possibly location for further scientific study (NASA)

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It’s been a worrying month for the health of Mars Expedition Rover Spirit. Two weeks ago, the embattled robot failed to wake up after three successive communication sessions, and then over the Easter weekend (April 12th and 13th), mission HQ noticed the rover had rebooted its systems at least twice during use of the high-gain antenna. The same thing happened on April 18th. In addition to this, Spirit has been suffering bouts of what seems to be an ‘electronic amnesia’, where the onboard computers have failed to record data onto their flash memory.

Today however, it would appear Spirit is still operational after over two weeks of remaining planted in the same position. It managed to enact commands sent from NASA to start driving once more, trundling 1.7 metres over the Martian regolith. She hasn’t given up the good fight quite yet

Since when have electronics on Earth ever lasted more than five years? I always seem to hit a two-year wall with my laptops when something nasty happens to the hardrive and/or motherboard (usually a day or two after the warranty runs out). But when we talk about the computers on board the Mars Expedition Rovers (MER), these electronics aren’t in the snug safety of my office; they are on the surface of an alien planet, dealing with extremes in temperature, high energy particles and copious amounts of dust. What’s more, the rovers were only designed to operate for a few months and yet they are still going strong, five years later. It’s the NASA mission that just keeps on giving.

I think this is what makes the MER mission so impressive for me. Not only are Spirit and Opportunity still operational, they are operating 20 times longer than their designated lifetime and they are notching up a very healthy odometer count. Their cumulative distance travelled is not measured in metres, or kilometres; it’s measured in tens of kilometres. They are giving us an unprecedented insight to the Martian surface, information that will shape our understanding of planetary science for generations to come.

But like any planetary mission, times can be tough, and both rovers have been tested to their engineered limits. Unfortunately, Spirit has been hit by a few more setbacks than Opportunity, but NASA has been able to find workarounds for each problem. The Mars Science Laboratory has a lot to live up to, I wonder if the MER mission will still be operational when the MSL finally touches down? Perhaps the next generation rover will have a robotic welcoming party!

The most recent issue for Spirit has been the flash memory problem. Flash memory helps the rovers store data even when they are powered down, but when the little rover forgets to actually store the data on the flash memory, something is obviously awry. In an attempt to make sure the rover can still take commands and to see if the computer problems persist, NASA ordered Spirit to travel 1.7 metres toward a target 150 metres away. All seems to be going well so far.

We expect we will see more of the amnesia events, and we want to learn more about them when we do,” said JPL’s Sharon Laubach, chief of the rover sequencing team, which develops and checks each day’s set of commands.

We decided not to wait until finishing the investigations before trying to drive again. Given Spirit’s limited power and the desire to make progress toward destinations to the south, there would be risks associated with not driving.”

Hopefully keeping the rover mobile will help NASA troubleshoot the recent computer problems, but so far, she’s still rolling over the Martian dirt…

Source: Physorg

Hubble Discovers a Strange Collection of White Dwarf… Dwarfs

Small helium white dwarfs can be caused by a binary partner (NASA)

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A collection of very odd white dwarfs have been discovered in a local globular cluster. Twenty-four white dwarfs (18 of them are new discoveries) have been spotted. Although these degenerate stars aren’t exactly an uncommon (they are the small sparkling remnants left over after star death), this particular set are unique; they are made from helium, rather than the “standard” carbon and oxygen. And they are small, even smaller than the smallest dwarfs.

How did this dense cluster of old stars evolve? It turns out their stellar material is being stolen, stifling their development…

Helium-core white dwarfs have only about half the mass of typical white dwarfs, but they are found concentrated in the center of the cluster,” said Prof. Adrienne Cool, from San Francisco State University, in a paper to be published in the Astrophysical Journal in July. “With such low masses, the helium-core white dwarfs ought to be floating all around the cluster, according to theory. The fact that we find them only in the central regions suggests that they have heavy companions — partner stars that anchor them to the cluster center.”

The Hubble observations show 18 previously undiscovered helium-core white dwarfs (Jay Anderson / Space Telescope Science Institute)
The Hubble observations show 18 previously undiscovered helium-core white dwarfs (Jay Anderson / Space Telescope Science Institute)
Cool and co-author Rachel R. Strickler believe they are seeing a case of stellar plasma theft by companion binary stars in the NGC 6397 cluster, approximately 7,200 light years away. These binary partners not only anchor these strange-looking white dwarfs in the centre of the cluster, they also have a huge role to play during the dwarfs evolution.

Before a white dwarf emerges from a planetary nebula, the parent star will have gone through the red giant phase (a phase our Sun is expected to go through in 4-5 billion years time). If this red giant has a binary partner (which seems to be the case of the 24 white dwarfs in this study), the outer layers of the puffed-up giant will be stripped away by the partner, stifling the red giant’s evolution. As mass is lost, the giant never gets the chance to burn helium and then progressively heavier elements such as carbon and oxygen in and around its core. Helium then becomes the key component of these smaller-than-usual white dwarfs.

This is the first time that helium-core white dwarf stars have been discovered in partnerships with other white dwarfs in a globular cluster,” Cool said. “This large sample allows us to answer questions about the mass and nature of the partner stars, and the prevalence of these kinds of binaries in the globular cluster.”

Binary stars are known to affect their partners fairly radically, they are even known to slow or even stop the development of black holes, stripping the outer layers of the dying star, stifling black hole development by removing mass from the parent star. However, not all questions have been answered.

From Cool’s calculations, 5% of the stars found in NGC 6397 should end their lives as dim helium-core white dwarf stars, but after studying Hubble data, many of these tiny dwarfs are missing. “It’s possible that these helium-core white dwarfs cool so slowly that they haven’t had time to get very faint yet,” Cool said.

There remains the possibility that the oldest binaries containing helium-core white dwarfs have actually been destroyed by interactions with other stars in the cluster. Regardless, this is a fascinating area of study. To understand how these ancient stars evolve will not only aid the development of globular cluster models, but it will provide an invaluable insight to how binary stars influence their partners.

Source: EurekAlert!