Posted on by Mike Simonsen

Asteroid Scheila Sprouts a Tail and Coma

(596) Scheila, the asteroid with a tail. Image credit: Peter Lake

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When is an asteroid not an asteroid? When it turns out to be a comet, of course. Has this ever happened before? Why, yes it has. In fact it was just announced December 12, 2010 that the asteroid (596) Scheila has sprouted a tail and coma! This is likely a comet that has been masquerading as an asteroid.

Taken from New Mexico Skies between 8h15m and 11h45m UT. The image is a stack of 10 x 600 sec exposures using a 20 inch RCOS and STL11K camera. Scale is 0.91 asec/px.. Image courtesy of Joseph Brimacombe

See an animation by Joseph Brimacombe at this link.

Steve Larson of the Lunar and Planetary Laboratory (LPL), University of Arizona first reported that images of the minor planet (596) Scheila taken on December 11th showed the object to be in outburst, with a comet-like appearance and an increase in brightness from magnitude 14.5 to 13.4. The cometary appearance of the object was confirmed by several other observers within hours.

A quick check of archived Catalina images of Scheila from October 18, November 2 and November 11 showed Scheila to look star-like, which is what asteroids look like from Earth. They just happen to be moving across the field of view in contrast to the fixed background stars. The image taken by Catalina on December 3rd shows some slight diffuseness and an increase in overall brightness. So, it appears this event began on or around December 3rd.

Upon hearing the news, there was some speculation that this might be evidence of an impact event. Had something crashed into asteroid Scheila? It seems unlikely, and this is a story we have heard before.

The asteroid discovered in 1979 and named 1979 OW7 was lost to astronomers for years and then recovered in 1996. It was subsequently renamed 1996 N2. That same year it was discovered to have a comet-like appearance, and many believed this was the signature of an impact between two asteroids. After years of inactivity 1996 N2 sprouted a tail again in 2002. One collision between two asteroids was unlikely enough. The odds of it happening again to the same object were essentially zero. What we had was a comet masquerading as an asteroid. This object is now known by its cometary name 133P/Elst-Pizarro, named after the two astronomers who discovered its initial cometary outburst.

The 2002 outburst and the discovery of more active asteroids showing mass-loss led to a paper (Hsieh and Jewitt 2006, Science, 312, 561-563) introducing an entirely new class of solar system objects, Main Belt Comets (MBC). MBCs look like comets because they show comae and have tails but they have orbits inside Jupiter’s orbit like main belt asteroids.

The most likely cause of the mass loss activity in MBCs is sublimation of water ice as the surface of the MBC is heated by the Sun. This is suggested most strongly by the behavior of the best-studied example, namely 133P/Elst-Pizarro. Its activity is recurrent, and it is strongest near and after perihelion, the point in its orbit nearest the Sun, like other comets.

MBCs are interesting to astronomers because they appear to be a third reservoir of comets in our solar system, distinct from the Oort cloud and Kuiper belt. Since we know of no way for these other reservoirs to have deposited comets in the inner solar system, the ice in MBCs probably has a different history than the ice in the outer comets. This allows researchers to study the differences in the Sun’s proto-planetary disk at three separate locations. This might lead to information on the Earth’s oceans, one of the continuing lines of investigation by solar system scientists.

Now it seems we have another MBC to add to the sample. And Scheila will probably be getting a new name soon. Asteroid (596) Scheila was discovered Feb. 21, 1906, by A. Kopff at Heidelberg. The 113Km in diameter ‘asteroid’ was named after an acquaintance, an English student at Heidelberg. In the future it will be called XXXP/Lawson or something similar, and Kopff’s Scheila will become just another footnote in the history of astronomical nomenclature.

Posted on by Jon Voisey

First Four Exoplanet System Imaged

HR 8799 system
One of the discovery images of the system obtained at the Keck II telescope using adaptive optics system and the NIRC2 Near-Infrared Imager. Image shows all four confirmed planets indicated as b, c, d and e in the labeled image. Planet "b" is a ~5 Jupiter-mass planet orbiting at about ~68 AU, while planets c, d, and e are ~7 Jupiter-mass companions orbiting the star at about 38, 24 and 14.5 AU. Credit: NRC-HIA, C. Marois & Keck Observatory

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Among one of the first exoplanet systems imaged was HR 8799. In 2008, a team led by Christian Marois at the Herzberg Institute of Astrophysics in Canada, took a picture of the system directly imaging three giant planets. The team revisited the system in 2009 – 2010 with the Keck II telescope and discovered a fourth planet in the system.

The new planet, designated HR 8799e, orbits at a distance of 14.5 AU, making it the innermost planet in the system. The other planets all orbit at distances of >25 AU. The images were taken in the near infrared where they are most noticeable because the system is relatively young (<100 Myr) and the planets are still radiating large amounts of heat from their formation.

The youth of these planets is part of what makes them an interesting target for astronomers. There exists a controversy in the community of planetary astronomers on the formation method of large planets. One theory states that planets form from a single, monolithic collapse that creates the entire planet’s mass at one time. Another possibility is that the initial collapse forms small cores early on, but then there is substantial growth later, as the planetesimal sweeps up additional material.

The discovery of the new planet challenges both theories. Marois states, “none of [the theories] can explain the in situ formation of all four planets.” Thus, a combination of both methods may be in use in the system. Several belts of dust are also known in the system which may help astronomers determine what modes of formation were present.

In particular HR 8799e is challenging to an in situ formation because the gravitational perturbations from the parent star should disrupt the formation of large gas planets within 20-40 AU from a single formation. Instead, the new planet would likely have had to been a core collapse with subsequent accretion, or alternatively, moved to its present location via migration.

HR 8799 comparison to solar system
Schematic representation of the HR 8799 planetary system compared to our solar system (viewed pole on and at the same distance as HR 8799). HR 8799 planet orbits are plotted assuming a pole-on view and circular orbits. A Kuiper Belt-like ring and an asteroid-like belt of dust, suggested by excess infrared light seen by the IRAS and ISO satellites, have been added. The HR 8799 dust disk is one of the heaviest detected by ISO and IRAS. It is thought that HR 8799e and HR 8799b dynamically interact with those dust disks in a way very similar to Jupiter with the asteroid belt and Neptune with the Kuiper Belt. Credit: NRC-HIA & C. Marois

Studying systems such as this may help astronomers better understand the formation of our own solar system. The paper notes that the HR 8799 “does show interesting similarities with the Solar system with all
giant planets located past the system’s estimated snow line (~2.7 AU for the Solar system and ~6 AU for HR 8799)”. Additionally, both have debris disks beyond the outer orbits with similar temperatures.

Different methods of detecting planetary formation necessarily turn up different types of systems. Radial velocity studies detect massive, close-in planets whereas direct imaging most easily finds more distant planets. These two apparent populations represent different modes of planetary formation and for a full understanding, astronomers will need a continuous sampling that merges the two. Marois notes that we are still far from this goal as “[w]e just do not have enough exoplanets detected by direct imaging (~6 so far)” to make any conclusions besides constraints from the non-detections occurring thus far. To truly merge these two populations, astronomers will likely need to wait until more systems are discovered.

Previously, some work has been done to estimate the composition of the atmospheres of the three planets already discovered in the system. These systems have been suggested to have cloudy atmospheres for CH4 and CO. According to Marois, his team is, “planning more observations on e, but it will be hard. We might have to wait for new instruments, like the Gemini Planet Imager to do it properly.” This new instrument “will put a ‘thumb’ on the star (or what we call a coronagraph) to physically block the star light and allow ‘easy’ detection of nearby faint planets.”

While this discovery is a first, it will certainly be one of a long line of exoplanet images. Marois is obviously excited about the ability to directly image planets. I asked him what the single most important thing he wanted readers to get from this research. His response was simple, “That we now have the telescopes and instruments to SEE planets orbiting other stars – that’s really cool! The exoplanet field is still very young and we have so much to learn.”

Posted on by Nancy Atkinson

Incredible Engineering Camera Views of the Space Shuttle in Action

This video is long, but totally worth the time to watch. Whenever there is any issue with the space shuttle, you’ll hear talk about the engineering camera footage that NASA can look at to review with a fine-tooth comb everything that took place during launch and ascent. Here is a look at some of that footage — in high resolution, and in super slow-motion — to provide a glimpse of the intricate details engineers look for. There’s narration, too, to inform you of everything you’re seeing. It’s great.

From the description:
Continue reading “Incredible Engineering Camera Views of the Space Shuttle in Action”

Posted on by Steve Nerlich

Astronomy Without A Telescope – Forbidden Planets

The theorised evolution of the circumbinary planet PSR B1620?26 b. Credit: NASA.

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Binary star systems can have planets – although these are generally assumed to be circumbinary (where the orbit encircles both stars). As well as the fictional examples of Tatooine and Gallifrey, there are real examples of PSR B1620-26 b and HW Virginis b and c – thought to be cool gas giants with several times the mass of Jupiter, orbiting several astronomical units out from their binary suns.

Planets in circumstellar orbits around a single star within a binary system are traditionally considered to be unlikely due to the mathematical implausibility of maintaining a stable orbit through the ‘forbidden’ zones – which result from gravitational resonances generated by the motion of the binary stars. The orbital dynamics involved should either fling a planet out of the system or send it crashing to its doom into one or other of the stars. However, there may be a number of windows of opportunity available for ‘next generation’ planets to form at later stages in the evolving life of a binary system.

A binary stellar evolution scenario might go something like this:

1) You start with two main sequence stars orbiting their common centre of mass. Circumstellar planets may only achieve stable orbits very close in to either star. If present at all, it’s unlikely these planets would be very large as neither star could sustain a large protoplanetary disk given their close proximity.

2) The more massive of the binaries evolves further to become an Asymptotic Giant Branch star (i.e. red giant) – potentially destroying any planets it may have had. Some mass is lost from the system as the red giant blows off its outer layers – which is likely to increase the separation of the two stars. But this also provides material for a protoplanetary disk to form around the red giant’s binary companion star.

3) The red giant evolves into white dwarf, while the other star (still in main sequence and now with extra fuel and a protoplanetary disk) can develop a system of orbiting ‘second generation’ planets. This new stellar system could remain stable for a billion years or more.

4) The remaining main sequence star eventually goes red giant, potentially destroying its planets and further widening the separation of the two stars – but it also may contribute material to form a protoplanetary disk around the distant white dwarf star, providing the opportunity for third generation planets to form there.

How a binary system might give birth to generations of planets: a) First generation planets - small and close-in - might be possible while both stars are on the main sequence (MS) and in close proximity to each other; b) Eventually one star evolves from the main sequence to the Asymptotic Giant Branch (AGB) - in other words, it goes red giant. c) The two stars spread further apart while stellar material blown off from the red giant builds a protoplanetary disk around the other star and second generation planets form; d) the second star eventually goes red giant giving the first star (now a white dwarf - WD) a protoplanetary disk which could create a third generation of planets. Credit: Perets, H.B.

The development of the third generation planetary system depends on the white dwarf star sustaining a mass below its Chandrasekhar limit (being about 1.4 solar masses – depending on its rate of spin) despite it having received more material from the red giant. If it doesn’t stay below that limit, it will become a Type 1a supernova – potentially lobbing a small proportion of its mass back to the other star again, although by this stage that other star would be a very distant companion.

An interesting feature of this evolutionary story is that each generation of planets is built from stellar material with a sequentially increasing proportion of ‘metals’ (elements heavier than hydrogen and helium) as the material is cooked and re-cooked within each stars’ fusion processes. Under this scenario, it becomes feasible for old stars, even those which formed as low metal binaries, to develop rocky planets later in their lifetimes.

Further reading: Perets, H.B. Planets in evolved binary systems.

Posted on by Nicholos Wethington

Akatsuki Update: Fuel Pressure Drop Likely Caused Insertion Failure

An image showing Venus from three of Akatsuki's different instruments, taken during a functions check of the probe. From left to right: the ultraviolet imager (UVI), 1 micron camera (IR1) and long wave infrared camera (LIR). Image Credit: ISAS

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While JAXA is still trying to get an exact handle on the problems that the Akatsuki probe sent to Venus encountered, there is a little bit of news leaking out. JAXA held a press conference last night, and the Yomiuri Shimbun newspaper has a brief recap of the conference. During some of the systems checks on the probe, it also took a few images of Venus, and many of the instruments on the probe appear to be working okay – it’s the engine that’s having the most problems.

Here’s what is known so far: Akatsuki’s engine did perform a burn to slow it down, but 152 seconds into the burn the fuel pressure dropped and the probe became unbalanced. Because the retrofiring of the rockets failed to slow down the probe enough for Venus to capture it, it was unable to enter into orbit around the planet, and then went into safe mode.

As to what caused the sudden drop in fuel, JAXA currently suspects that there is a damaged pipe or valve that reduced the flow of helium into the engine, but that is still speculative. As the engine burns propellant (Akatsuki uses a hydrazine/nitrogen tetroxide engine), helium flows into the tank to maintain the pressure. Something failed in the helium injection flow, and precipitated a drop in internal tank pressure, reducing the flow of propellant and causing the engines to stop burning.

The ceramic nozzle of the engine is also thought to have been damaged by the misfiring, which may make the task of trying to get the probe to Venus when the chance comes around again in six years a daunting one.

An image of Venus taken by Akatsuki's Ultraviolet imager (UVI) at the 365 nm wavelength, the color is artificial. Field of View: 12 deg x 12 deg Image Credit: ISAS

JAXA is planning on doing some tests on the ground to maybe come to a workaround of this problem. There seems to be plenty of fuel left, which is good news, but the damaged nozzle is not. Maybe they’ll call in some Hayabusa team members, and pull it through.

The Christian Science Monitor reported yesterday that there is some speculation that something may have struck the probe, though this most recent press conference from JAXA makes no mention of it.

Also, Emily Lakdawalla at The Planetary Society Blog reprinted some tweets translated from Japanese that summarize details from the press conference, as well as the Yomiuri Shimbun article.

Source: Yomiuri Shimbun, ISAS, the Planetary Society Blog,

Posted on by Nicholos Wethington

Nanosail-D Update: Things Look Grim

Artist concept of Nanosail-D in Earth orbit. Credit: NASA

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We reported the successful ejection of the Nanosail-D nanosatellite from the satellite that it was launched with earlier this week. Well, the most recent release from NASA states that things might have turned out otherwise. Not only has the sail potentially failed to deploy, it’s currently unclear if the nanosatellite was even ejected.

In NASA’s own words on the mission site:

At this time, it is not clear that NanoSail-D ejected from the Fast, Affordable, Science and Technology Satellite (FASTSAT) as originally stated on Monday, Dec. 6. At the time of ejection, spacecraft telemetry data showed a positive ejection as reflected by confirmation of several of the planned on orbit ejection sequence events. The FASTSAT spacecraft ejection system data was also indicative of an ejection event. NanoSail-D was scheduled to unfurl on Dec. 9 at 12:30 a.m., and deployment hasn’t been confirmed. The FASTSAT team is continuing to trouble shoot the inability to make contact with NanoSail-D. The FASTSAT microsatellite and all remaining five onboard experiments continue to operate as planned.

What a bummer. This is all we have to go on right now – we’ll keep you posted as the situation develops over the weekend.

Source: NASA press release

Posted on by Nancy Atkinson

WISE Captures an Infrared Shock Wave

This oddly colorful nebula is the supernova remnant IC 443 as seen by WISE. Image credit: NASA/JPL-Caltech/UCLA

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From a JPL press release:

A circular rainbow appears like a halo around an exploded star in this new view of the IC 443 nebula from NASA’s Wide-field Infrared Survey Explorer, or WISE.

When massive stars die, they explode in tremendous blasts, called supernovae, which send out shock waves. The shock waves sweep up and heat surrounding gas and dust, creating supernova remnants like the one pictured here. The supernova in IC 443 happened somewhere between 5,000 and 10,000 years ago.

In this WISE image, infrared light has been color-coded to reveal what our eyes cannot see. The colors differ primarily because materials surrounding the supernova remnant vary in density. When the shock waves hit these materials, different gases were triggered to release a mix of infrared wavelengths.

The supernova remnant’s northeastern shell, seen here as the violet-colored semi-circle at top left, is composed of sheet-like filaments that are emitting light from iron, neon, silicon and oxygen gas atoms and dust particles heated by a fast shock wave traveling at about 100 kilometers per second, or 223,700 mph.

The smaller southern shell, seen in bright bluish colors, is constructed of clumps and knots primarily emitting light from hydrogen gas and dust heated by a slower shock wave traveling at about 30 kilometers per second, or 67,100 miles per hour. In the case of the southern shell, the shock wave is interacting with a nearby dense cloud. This cloud can be seen in the image as the greenish dust cutting across IC 443 from the northwest to southeast.

IC 443 can be found near the star Eta Geminorum, which lies near Castor, one of the twins in the constellation Gemini.

Posted on by Nancy Atkinson

Satellite Images Show Dueling Snowstorms in the US and UK

The mid-section of the US got a dose of winter weather, as seen in this satellite image from NASA's Terra spacecraft, taken on Dec. 7, 2010. Credit: NASA

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OK, let’s duke it out. Who had it worse this past week as far as wintery weather: the entire United Kingdom, or the middle part of the United States? We’ll the the satellite images tell story.

The Moderate Resolution Imaging Spectroradiometer (MODIS) on NASA’s Terra satellite acquired the image above on December 7, two days after the weekend snow storm. A swath of white defines the path of the storm from Minnesota to Kentucky in the image. Weather predictions look there is more on the way this weekend.

And for the UK:

The UK covered in snow, as seen on Dec. 8, 2010. Credit: NASA's Aqua satellite.

Snow and clouds present an almost uniform white to this satellite image. Snow extends from Northern Ireland southward past Dublin, and from Scotland southward into England. Snow cover stops short of London; the white expanses in that area are clouds. Snow and clouds present an almost uniform white to the satellite sensor, but clouds can be distinguished from the underlying snow by their billowy shapes and indistinct margins.

The United Kingdom Met Office forecast that the cold weather would gradually loosen its grip on the region. For December 9 and 10, 2010, the Met Office forecast rain, but also warned of widespread icy roads.

Source: NASA Earth Observatory

Posted on by Nancy Atkinson

How Are You Celebrating the Year of the Solar System?

There are a lot of solar system space missions coming up, plus – as always – a plethora of astronomical events taking place, so NASA has decided to declare the “Year of the Solar System” (YSS). But this year is so big, it won’t fit into an Earth year — however, a Martian year just about covers it, so from now until August, 2012 we’re celebrating.

“During YSS, we’ll see triple the usual number of launches, flybys and orbital insertions,” said Jim Green, the director of Planetary Science at NASA headquarters. “There hasn’t been anything quite like it in the history of the Space Age. History will remember the period Oct. 2010 through Aug. 2012 as a golden age of planetary exploration.”

Below you’ll see a list of mission activities that will take place, but also, the YSS organizers will have special events – both online and at various venues – to help us all celebrate.

One project near and dear to my heart is the 365 Days of Astronomy podcast, which will be continuing at least through 2011. Universe Today readers, you’d help me out A LOT (I’m the 365 Days project manager) by signing up to do a podcast. Podcasting is an easy and wonderful way to share your knowledge, experiences and love of astronomy or space. We give you lots of info about what you need to do to created a podcast. Check out the website, the calendar for available dates in 2011, and you can contact me directly to sign up for a date!

For other things associated with the YSS, there are also activities and materials available for classrooms and teachers, afterschool programs, astronomy clubs and more.

Right now, during December and January, the activities focus on investigations of our planetary family tree. Conduct the Explore the Celestial Neighborhood … in Your Neighborhood! activity and others fun projects that examine what a planet is and how we investigate planets.

There is also information on how to observe the total lunar eclipse on December 21, or activities to simply note the change in lunar phases over the course of a month.

You can also submit photographs, artwork, music, or words of your YSS experiences at the Share Your Stories page.

This artist's illustration shows how the Sun would have looked from Carl Sagan Memorial Station at a specific time each month on Mars over the course of a Martian year. (Credit: Dennis Mammana)

As far as the solar system missions going on we’ve already enjoyed the flyby of Comet Hartley 2 by the Deep impact/EPOXI spacecraft, and the NASA O/OREOS (“Organism/ORganic Exposure to Orbital Stresses,”) spacecraft was launched in November 2010, to study “the durability of life in space.” It is a nanosatellite (a cubesat), only 5.5 kilograms in mass, and we’ll certainly be hearing more about that spacecraft soon.

NASA NanoSail-D was also launched by the same rocket, and it has been ejected from the spacecraft but hasn’t yet unfurled its sails. We’ll post something as soon as any news on that emerges.
Here are more upcoming mission highlights as part of the YSS:

Stardust NExT encounters comet Tempel on February 14.

MESSENGER enters an orbit around the planet Mercury on March 18.

Dawn begins its approach to the asteroid Vesta in May, for a mission between 2011 and 2012. It will also visit the dwarf planet Ceres in 2015.

The Juno spacecraft will launch to Jupiter in August 2011. It will study the planet’s composition, gravity field, magnetic field, and polar magnetosphere.

GRAIL, or the NASA Gravity Recovery and Interior Laboratory (GRAIL) spacecraft will launch for a mapping mission to the Moon in September 2011.

Curiosity, or the Mars Science Lab will launch in November 2011. This is a big, car-sized rover that will look for potential habitable places, and more, on Mars. Curiosity is slated to land in August, 2012.

Posted on by Nancy Atkinson

Here’s Your Chance To Spread the Joy of Astronomy Around the World

Donate your used astronomy books to the Astro Book Drive!

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Astronomy is one of the oldest sciences, and one of the most popular amateur hobbies around the world. In fact, there are thousands of astronomy clubs and groups across the globe, but in many developing countries they don’t have the resources to help educate their their members, as well popularize astronomy for students and the public.

“The enthusiasm of most of these groups are vast but they always come across the lack of resources to conduct programs,” said Thilina Heenatigala, from the Sri Lanka Astronomical Association, who has been instrumental in organizing astronomy book drives for fledgling astronomy clubs in developing countries the past few years.

Astro Book Drive is a project that works on helping improve astronomy education in developing countries by sharing resources. Right now, Astro Book Drive is gathering books and other resources for an astronomy club in Indonesia.

So, c’mon – you know you have some astronomy books, pamphlets and other items that you’d like to donate!

“Even though we are much advanced in technology and internet has a vast amount of resources,” Heenatigala told Universe Today, “most of the groups from developing countries are lacking resources to conduct astronomy programs and educate people. As coming from a developing country myself, I can tell you that one of the most basic, yet powerful ways to bring astronomy to developing countries is through the simple gift of books.”

If you’re like me, you probably have a surplus of astronomy materials lying; these materials are valuable to groups from developing countries.

“This is a global effort and anyone/group welcome to donate what they have, even one book can make big difference,” said Heenatigala. “I’m hoping to keep the book drive running from December through February 2011.”

The group from Indonesia, langitselatan (LS) – Southern Skies – is an astronomy communication and educator media in Indonesia run by young group of astronomy enthusiasts with the vision of getting astronomy in the local media, astronomy education and awareness throughout the country. Heenatigala said LS has been working tirelessly over the years to achieve these by conducting star parties, telescope training, teachers training, hands on activities, story telling session, astronomy discussion and talk shows and astro-presentation.

To expand their efforts, LS hopes to build a small library which will be used by the members, students and the local community. Through the library project, they hope to increase the reading habits of young students and teachers as well. To achieve their dream of setting up a library to improve astronomy education in Indonesia, Astro Book Drive calls the international community to donate Astronomy reading materials.

There are other book drives as well, and will probably be more coming up in 2011. The Astro Book Drive project was started in 2009 as part of the International Year of Astronomy.

“Usually the procedure is to get a group/institutes from a wealthy country to run a book drive for a group in developing country, where they donate from 3 – 10 boxes of books. But for the Indonesian book drive, I had to put an open call since it’s an effort to set up an Astro Library there.”

For more information on specifically the book drive for Indonesia, see this link

Astro Book Drive website main page.

You can see a list of projects at this link.: