Teenage asteroid hunters
Posted: Tuesday, October 09, 2007 7:18 PM by Alan Boyle
What happens when you turn college freshmen and sophomores loose to sift through one of the best surveys of the night sky, looking for asteroids? You get lots and lots of sightings, pointing to as many as 1,300 newly discovered mini-worlds.
The project at the University of Washington is helping students learn how to do astronomy even as it contributes to the fast-growing store of knowledge about minor planets. And one of the coolest things about the quest is that the students will be able to name celestial bodies after themselves and hundreds of their best friends.
The students didn't start out searching for the asteroids themselves. What they were really looking for were supernovae, exploding stars that can provide revelations on topics ranging from stellar evolution to the size of the universe and the nature of dark energy. Under the aegis of the university's Pre-Major in Astronomy Program, or Pre-MAP, the teenage searchers used computer software to comb through data from the Sloan Digital Sky Survey.
SDSS / UW |
In this image from the Sloan Digital Sky
Survey, the white arrow points to a
previously known asteroid that has been
given a number (55480) as well as a
provisional designation (2001 UO20) but
not yet a name. Click on the image to see
a larger version that indicates movement.
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Every time there was a blip that showed up on one image but not on earlier images, that was flagged as a potential supernova blast. The problem was that the vast majority of those blips were actually asteroids moving through the telescope's viewing field.
"All these asteroids are contaminants for the supernova search," Andrew Becker, an astronomy professor at the University of Washington and the research adviser for Pre-MAP, told me today.
In a university news release, Becker said he turned those contaminants into a fresh science project for the Pre-MAP teams in 2005 and 2006.
"We decided that rather than get frustrated by the asteroids, we should do some science and note details about our observations," he said. "I kept asking the students what they had found, and they kept saying, 'More asteroids. No supernovae, but lots of asteroids.'"
Eventually, the undergraduates - Amy Rose and Amber Almy (who are now juniors) and Kenza Arraki, A.J. Singh and Kathryn Smith (now sophomores) - turned in about 350,000 sets of doubled-up sightings, showing movement of faint objects through the star field over a matter of minutes.
Those observations were submitted to the International Astronomical Union's Minor Planet Center in Cambridge, Mass. - which is the world's clearinghouse for the lesser objects in our solar system (including asteroids, comets, and yes, even Pluto).
Gareth Williams, the center's associate director, told me that the hundreds of thousands of observations were winnowed down using a "rather nifty" method - in which computers linked up potential sightings of the same object over short periods on different nights, then figured out which objects had been seen before.
UW |
Amber Almy
UW |
Kenza Arraki
UW |
Amy Rose
UW |
A.J. Singh
UW |
Kathryn Smith
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Right now, the list of candidates stands at just over 1,300. It could take months or even years more to verify the orbits of all those candidates, but Williams thinks it's a safe bet that at least 1,000 of the objects discovered by the Pre-MAP team will become eligible for naming.
That's when the fun begins: It's generally up to the discoverers of minor planets to submit names for IAU approval, subject to a few rules (for example, don't try to name an asteroid after Hitler). Just last week, the IAU announced that one asteroid has been named after "Star Trek" actor George Takei (a.k.a. Sulu). In a couple of years, the five students might well have the right to name hundreds of asteroids each.
"I don't think dividing them up will be an issue; I know that I don't have 1,300 friends!" sophomore Kathryn Smith, a 19-year-old from Oregon who wants to become a research astronomer, told me today in an e-mail. "I would like to designate a few with family names, but I'm open to suggestions and requests."
Does Smith's professor hope that one of those names will be asteroid Andrewbecker? "Eventually, yeah," Becker told me.
But there's more to the asteroid search than the name game. "This is very good experience for students in astronomy," said Brian Marsden, the Minor Planet Center's director emeritus. And the students themselves agree.
"It's an amazing feeling - I feel like I'm jumping into research," Amy Rose, a junior from Washington state who is majoring in physics and astronomy, said in today's news release. "It's not just taking tests and going to class."
Smith said she was "amazed by the legitimacy of the research I conducted in my freshman year of college."
"Asteroid research is especially 'close to home,'" she told me, "because asteroids really are close to earth, especially when compared with other celestial bodies that are literally millions of light-years away."
You might be wondering how a band of teenagers could discover so many asteroids that have eluded the experts for all this time. The Minor Planet Center's Williams explained that there were a couple of factors at work.
For one thing, the software to deal with bunches of short-period observations was developed only recently to deal with the Pre-MAP data. "We had to rework some of our procedures," Williams said.
The other main factor is that no one had really focused on mining the data from the Sloan Digital Sky Survey for asteroid sightings before. The Sloan sky scan picks up objects as dim as magnitude 23 - which would be too faint for most of the telescopes involved in asteroid surveys. The survey's telescope in New Mexico was really designed for spotting faint objects beyond our galaxy - like, um, supernovae.
"The extraction of solar system data is a useful bonus from the project," Williams said. "Becker has been going into it with great gusto in recent months, and of course they're getting fainter than the main surveys. So they're essentially sampling virgin territory."
Even if all 1,300 of Pre-MAP's sightings turn out to be newfound asteroids, that's a mere drop in the cosmic bucket. There are more than 14,000 named asteroids, and about 150,000 more that have numbers but don't yet have names. In all, the Minor Planet Center has catalogued roughly 335,000 solar-system objects, with plenty more yet to be discovered.
Williams said the Pre-MAP team has still more potential asteroid sightings in the hopper, which means the list of names that are needed could grow as well. Hmm ... that sounds like the perfect way for young asteroid-hunters to make themselves even more popular on campus.
