Posted on by Nancy Atkinson

Re-use, Recycle and Share Your Spacecraft to Find Exoplanets

How do you get the most out of one spacecraft and find exoplanets in the process? Re-use, recycle and share. The spacecraft bus that brought the Deep Impact “impactor” to comet Tempel 1 in July of 2005 is still out in its heliocentric orbit and has been put to work double time where two new missions are sharing the same spacecraft. The combined operation is called EPOXI, which is a combo-acronym of the two separate missions. The Deep Impact Extended Investigation (DIXI) of comets will observe comet 103P/Hartley 2 during a close flyby in October 2010. But of current interest is the other half of the dynamic duo, called the Extrasolar Planet Observation and Characterization (EPOCh) which is observing stars already known to have transiting giant planets. Since the orbital plane of the giant planet has been identified, EPOCh is looking in that same plane for planets closer to Earth size. So far, 4 new planets have been found with this spacecraft, using the transit method. But EPOCh is also looking back at our home planet, using Earth as a baseline to be able to identify features on an exoplanet, such as continents and oceans.

The EPOXI team has focused most of its attention on the star GJ436. This red dwarf star which is 32 light-years from Earth has a Neptune-sized planet that transits in front of the star. Spitzer observations have shown its orbit to be oval shaped, or eccentric. “That virtually guarantees there is a second planet in this system,” said Drake Deming, Deputy Principal Investigator for EPOXI . “We have three weeks of data on this system. The habitable zone corresponds with where we believe this planet to be, and we hope to be below the Earth as far as the size.”

Earth observations will help to calibrate future observations of Earth-like exoplanets. EPOXI obtained a particularly interesting view of the Earth on May 29, when the Moon passed in front of the Earth as viewed from the spacecraft. This “transit” of the Moon is an event that may also be observed to occur for Earth-like exoplanets, and it may help us to deduce the nature of their surface features.

Deming and Deep Impact team leader Michael A’Hearn both said that sharing the spacecraft has gone smoothly. The EPOCh mission will continue until August 30 of this year, with the option of doing more planet searching if the team is able to preserve the margin of hydrazine fuel on board. “But,” said Deming, “when the hydrazine runs out we’re done for sure.”

Source: AAS press conference

Posted on by Mark Mortimer

Book Review: Canada’s Fifty Years in Space – The COSPAR Anniversary

Technical ability signals a country’s advent into first world status. Amongst abilities, space travel sets the bar as paramount. Some nations with ready access to many people and large quantities of resources ascended and proclaimed their might. Other nations technical prowess came otherwise. Gordon Shepherd and Agnes Kruchio describe one such in their book “Canada’s Fifty Years in Space – The COSPAR Anniversary“. In it, they show that a nation’s limitations in people and resources doesn’t necessarily equate to a lack of technical ability or capability.

Canadians built the Alouette I satellite over a 4 year duration and saw it successfully launched in September 1962. Other than the US and the USSR, no other country had achieved such a feat. Yet, this wasn’t a one-of event. This satellite was a continuance of a Canadian specialty, the study of electron densities above the Earth. Following the launch, further studies added to the scientific knowledge of the aurora and the magnetic fields of the north. Expanding beyond this, Canadians have since studied life sciences and pushed the envelope in the field of robotics. Hence, even without an indigenous launch capability, Canada has made a positive impact in space science by carefully picking and choosing.

Shepherd and Kruchio’s book shows that Canadians have had a busy and productive 50 years in the field of space science. Their book starts with events a little bit earlier than in the title, with funding for studies being available in the early 1930s. Then, adventurers traveled into the cold Arctic winters to take timed exposures of Northern Lights. These stalwart types braved polar bears and isolation to gather the first organized review of one of nature’s most pleasant spectacles. But, their interest wasn’t all for pretty pictures. This book also shows their contributions were a true beginning into the study of the protective ionosphere about Earth. It also shows that as the years advanced, funding expanded. And, consequently, so did research. Rockets and balloons replaced ground-based photography. More people joined in. Yet, as becomes evident, the shear cost of doing research placed more and more restrictions on the scientists. With a fairly recent shift to remote sensing and astronauts, Canada now looks to fund applications of space science rather than delve in pure research. Thus, though barely two generations have passed, this book shows a busy past and a fundamental shift in one nation’s space research.

This book by Shepherd and Kruchio effectively brings together many aspects of Canada’s space science history. Vivid recollections recall the times of luminaries such as Dan Rose, Balfour Currie and Frank Davies. We read of programs that sprout from deep in the rooms of University of Saskatchewan, the launch pads at the Churchill Rocket Range and the laboratories at the DRTE. Devices such as ionosondes, interferometers and Lidar have brief technical descriptions and then a bit longer passage describing their use. Amongst all this data and information, the occasional reprints of some personal diary entries markedly and pleasantly contrast the otherwise dry prose.

As well as being dry, this book’s scope is another weakness. Typically a review of an expanding research field has more entries at the end than the beginning. This book, however, has most of its focus on the early and mid-term, when Canadians were studying the ionosphere. In comparison, the most recent science appears, briefly, toward the end and is like a collection of press releases. This, coupled with an out-of-place first chapter on COSPAR’s formation, detract from an otherwise intriguing review of science and scientists.

Yet, Canadian’s who are interested in knowing more of their country’s space accomplishments would enjoy this book. As well, industry watchers who wonder where some national organizations come from and go to might just get some answers within. And, anyone who thinks they’re too small to contribute could read this and get a great boost to their ego.

From so many perspectives, fifty years is an amazingly short time. But, in the field of science and technology, it’s a vast duration. Gordon Shepherd and Agnes Kruchio’s book “Canada’s Fifty Years in Space – The COSPAR Anniversary” describe some of the scientific progress made by Canadians. With Canada and many more countries contributing to space science, the future years should see equal or greater accomplishments.

Posted on by Fraser Cain

Carnival of Space #56

With the Mars Phoenix Lander settling down on the surface of Mars, many posts in the this week’s Carnival of Space focused on this. Check out all the entries, posted this week at the Lifeboat Foundation Blog.

Click here to read the Carnival of Space #56

And if you’re interested in looking back, here’s an archive to all the past carnivals of space. If you’ve got a space-related blog, you should really join the carnival. Just email an entry to [email protected], and the next host will link to it. It will help get awareness out there about your writing, help you meet others in the space community – and community is what blogging is all about. And if you really want to help out, let me know if you can be a host, and I’ll schedule you into the calendar.

Finally, if you run a space-related blog, please post a link to the Carnival of Space. Help us get the word out.

Posted on by Astronomy Cast

Podcast: The Scientific Method

You’ve heard me say it 90 times: “How we know what we know.” But how do we know how we know what we know? So astronomers like all scientists use the scientific method. Without the scientific method we’d probably still think the Earth is flat, only a few thousand years old and the center of the universe. But with the scientific method everything changes. From biology, to chemistry, to physics, to astronomy it is impossible to count the number of changes that have happened to human society because of changes brought about from the scientific method. In this episode we tell you about what the scientific method is, how you can use it to improve your life, and discuss why gravity isn’t just a theory.

Click here to download the episode

The Scientific Method – Show notes and transcript

Or subscribe to: astronomycast.com/podcast.xml with your podcatching software.

Posted on by Fraser Cain

Astronomers Weigh the Coolest Brown Dwarfs

Pity the poor brown dwarf; a star wannabe. With as little as 3% the mass of the Sun, brown dwarfs don’t have the gravitational pressure needed to ignite fusion in their cores. Instead of blazing bright, they’re dim little objects that smolder quietly for eons. They’re small and dim, and this makes them almost impossible to locate, let alone weigh. But that’s what a team of astronomers have done. They’ve gathered accurate measurements of the lowest mass, free-floating objects ever seen.

When it comes to being a star, mass is everything. Once a star gets down below a certain point – about 7% the mass of the Sun – it doesn’t have enough pass to ignite nuclear fusion in its core. While our Sun’s temperature is nearly 6000 Kelvin, brown dwarfs are only a little hotter than an oven at 700 Kelvin. A typical brown dwarf will put out 1/300,000th the energy of the Sun. Like I said, cool and hard to find.

The most accurate way of determining mass is by looking for a binary object, where a brown dwarf is orbiting another object, like a higher-mass star (or another brown dwarf). Astronomers from Hawaii and Australia did just that.

Think back to your high school physics class. Johannes Kepler first proved in the 17th century that the total mass of any binary system can be determined by precisely measuring the orbit’s size and how long it takes for the two objects to complete one orbital cycle. If you can accurately measure the orbital periods, the mass is easy to calculate.

It’s measuring the orbital periods that was the trick. Here’s Trent Dupuy from the University of Hawaii’s Institute for Astronomy, “these are very challenging measurements, because brown dwarf binaries have tiny separations on the sky and orbit each other very slowly. We needed to obtain the sharpest measurements that are possible with current telescopes to precisely monitor their motion.”

They gathered their data using the 10-meter Keck II Telescope atop Hawaii’s Mauna Kea. The Keck II is built with an adaptive optics system that’s absolutely perfect this kind of task.

The team measured the mass of two brown dwarf binaries. One was composed of two “methane” brown dwarfs – the coolest kind of brown dwarf. The total mass of the two objects was about 6% of the Sun, so 3% of the Sun each. The other pair was a set of warmer, “dusty” brown dwarfs, with 11% the mass of the Sun – so 5.5% each.

Original Source: IFA News Release

Posted on by Nancy Atkinson

Famous People Wandering the Halls of AAS

Walking the halls of the AAS meetings we found Galileo Galilei, who actually looks pretty good for being 440 years old. He had a briefing with officials from the inquisition (the media) and said that he has just returned from Rome on his book tour, promoting Sidereus Nuncius (Starry Messenger). But here, he met up with another author, Dava Sobel, who wrote “Galileo’s Daughter,” and is in St. Louis to speak at a public lecture in conjunction with the AAS meeting.

The International Year of Astronomy (IYA) which celebrates 400 years since Galileo looked through his telescope, is being promoted heavily here at the AAS meeting, which includes educational workshops and symposiums sponsored by the Astronomical Society of the Pacific, highlighting special educational programs specifically created for IYA.

Speaking of education, Galileo says that being a professor is difficult. “The work is hard and the pay is terrible,” he said. “I’m looking to invent something here during the next year which might give me some fame.”

Galileo was played by Mark Thompson, an impersonator who actually is an amateur astronomer. Although he kind of transited back and forth to the present and the past, he said he’s currently living in IYA time, which means he hasn’t yet built his telescope. That will happen coming up next year.

More information about Mark Thompson as Galileo.

Posted on by Fraser Cain

Planet Discovered with Only 3 Times the Mass of the Earth

Most of the planets found to date have been massive and orbiting their parent stars at a fraction the orbit of Mercury – the hot jupiters. They’re interesting to astronomers, but the big goal is going to be finding Earth-mass planets orbiting other stars. To do this, astronomers are looking for less massive stars, where the effects of gravity from a smaller, Earth-sized planet will be easier to spot. Today, an international team of astronomers announced they have found a planet with only 3 times the mass of the Earth orbiting a tiny star that can barely support nuclear reactions.

The announcement of this new planet, known as MOA-2007-BLG-192Lb, was made at the 212th meeting of the American Astronomical Society held in St. Louis from June 1-5, 2008. Researchers from several universities, including the University of Notre Dame presented their findings.

The star is known as MOA-2007-BLG-192L, and it’s located about 3,000 light-years away. It’s probably not actually a star, with only 6% the mass of our own Sun. These objects are classified as brown dwarfs, because they don’t have enough mass to sustain nuclear reactions in the core. I say “probably” because the uncertainty of the observations might put it into the very low end of a hydrogen-burning star.

Researchers found the planet and star using the gravitational microlensing technique. This is where two stars line up perfectly from our point of view here on Earth. As the two stars begin to line up, the foreground star acts as a lens to magnify and distort the light from the more distant star. By watching how this brightening happens, astronomers can learn a tremendous amount about the nature of both the foreground and background star.

In this case, there was an additional gravitational distortion from the planet orbiting the foreground star MOA-2007-BLG-192L, which astronomers were able to tease out in their data.

This technique demonstrates the gravitational microlensing might be one of the best ways to find Earth-mass planets. In fact, the researchers think the technique will turn up the first one. Here’s David Bennett, from the University of Notre Dame: “I’ll hazard a prediction that the first extra-solar Earth-mass planet will be found by microlensing. But we’ll have to be very quick to beat the radial velocity programs and NASA’s Kepler mission, which will be launched in early 2009.”

Unfortunately, the lensing events can only happen one time. The foreground star will probably never be seen again since it was only revealed by the two stars lining up. Astronomers have to work fast to get all their data collected.

Original Source: University of Notre Dame News Release

Posted on by Fraser Cain

AAS Meeting in St. Louis, June 1-5

It’s going be another busy week of space news. That’s because thousands of professional astronomers have descended into St. Louis for the 212th meeting of the American Astronomical Society. We’re trying to outdo our previous effort with full coverage of the meeting. Phil Plait, Pamela Gay, Chris Lintott are at the conference, as well as Universe Today’s Nancy Atkinson. I wasn’t able to go this time around, but I’ll be helping out from afar.

I’ll warn you right now, there’s going to be an enormous amount of news. I’ve seen some of the embargoed press releases (shhhh, don’t tell anyone), and there are going to be some really interesting discoveries getting announced.

Stay tuned for our coverage on Universe Today, but if you really want the full coverage from everyone, check out Astronomy Cast LIVE.

Posted on by Nancy Atkinson

How To Weigh a Black Hole: Just Look At Its Galaxy

Traveling to distant locations, like Andromeda, could have interesting consequences. Credit: NASA

My father was a rancher, who had the uncanny ability to accurately estimate the weight of each animal in his herd of cattle simply by looking at them. Today, at the American Astronomical Society meeting in St. Louis, astronomers announced a new, simple way of determining masses of super-massive black holes by just looking at images of galaxies. Dr. Marc Seigar from the University of Arkansas at Little Rock has been studying images available at the Hubble Space Telescope archive site, and looking at the how tightly the galaxy’s arms wrap around itself in relation to the size of the galaxy’s super-massive black hole. “This provides a much simpler method of determining black hole mass,” said Seigar. “You just need an image of a galaxy and you can measure the tightness of the spiral structure. This can easily be applied to distant galaxies, up to 8 billion light-years away.”

Usually astronomers determine masses of super-massive black holes by looking at how fast the stars are moving in the central regions of the galaxies. But that method only works for nearby galaxies. Astronomers have been looking for a new method for galaxies that are father away. This new inexpensive method can use already-existing images, as Seigar has used from the Hubble Site.

Seigar and his team looked at photographs of 27 spiral galaxies including the Milky Way and the Andromeda Galaxy. They observed galaxies with the smallest black holes had spiral arms with angles up to 43 degrees between the arms and the central bulge. Those with the biggest black holes had spiral arms at angles of only 7 degrees between the arms and the bulge.

Seigar said its also possible that the main factor in determining the mass of a super massive black hole is the amount of central concentration of dark matter in a galaxy. “We think dark matter is driving most of the relationships between black holes and their galaxies,” he said. “The masses of these black holes can be determined indirectly from the characteristics of the light emitted from in falling material.”

Seigar will continue to use this method to verify his findings, as well as looking at other aspects. “We have to determine if the relationship between spiral arms and black hole mass evolves over time.”

Source: AAS press conference

Posted on by Nancy Atkinson

Phoenix Digs on Mars

Phoenix’s first dig in the Martian soil. Image credit: NASA/JPL-Caltech/ University of Arizona

The Phoenix lander used its robotic arm scoop to dig up soil on Mars surface for the first time during its activities during its seventh day on the Red Planet. The image above shows the hole dug by Phoenix, and below is a picture of the scoop itself, with the Martian soil inside.

The plan was to do a test dig and then dump the soil. If that works correctly, then Phoenix will dig another scoop and bring it to the TEGA device on board the lander, the Thermal and Evolved Gas Analyzer, a “furnace” and mass spectrometer instrument that scientists will use to analyze Martian ice and soil samples.

During its previous day’s activities on Sol 6, Phoenix reached out and touched Mars with its robotic arm scoop to make an impression on the Martian surface. And please, no conspiracy theories here, but the impression looks like a footprint, and the Phoenix scientists have dubbed the mark “Yeti.” Touching the surface was a preliminary test for the robotic arm and scoop, to make sure everything was working correctly before making the first scoop.

However, the TEGA device has experienced an intermittent short circuit, and the TEGA scientists are developing a procedure to work around the problem. But Phoenix can still deliver the soil sample to TEGA, and the sample can be held there until the device is working.

Original News Source: Phoenix