Featured Research

from universities, journals, and other organizations

Astronomers Track Down Asteroids In Hubble Space Telescope Archive

Date:
March 10, 1998
Source:
National Aeronautics And Space Administration
Summary:
Astronomers have stumbled on an unusual asteroid hunting ground: the thousands of images stored in the Hubble Space Telescope archive.

Astronomers have stumbled on an unusual asteroid hunting ground: the thousands of images stored in the Hubble Space Telescope archive.

The hunt, by Robin Evans and Karl Stapelfeldt of NASA's Jet Propulsion Laboratory, Pasadena, CA, has yielded a sizable catch of small asteroids -- about 100. Their preliminary analysis suggests that a total population of 300,000 small asteroids -- essentially rocks just over half a mile to two miles wide (1-3 kilometers) -- are orbiting between Mars and Jupiter in a band of space debris known as the main belt. Currently, there are 8,319 confirmed main-belt asteroids whose orbits have been measured, and about the same number have been sighted but not confirmed.

Most astronomers stalk the Hubble archive for bigger game, such as quasars, distant galaxies, and supernovae, but Evans and Stapelfeldt have discovered that the pursuit of smaller prey such as asteroids can be equally successful.

Over a three-year period, the two astronomers and their collaborators have searched through more than 28,000 Wide Field and Planetary Camera 2 (WFPC2) images, looking for wide, looping streaks of light, the telescope's tell-tale signatures of asteroids. Most of the ones they found are too faint to be observed by current ground-based search programs. Hubble captures their images purely by accident: Nearby asteroids inevitably wander across the telescope's field of view while other, higher priority targets are being observed.

"The archive images are distributed fairly evenly across the sky, so we find asteroids according to both their position in the sky and their number," Evans said. "As expected, we see the asteroids concentrated towards the ecliptic plane and we see small asteroids because they are the most numerous. Small main-belt asteroids such as these are the ones most likely to evolve into Earth-crossing asteroids due to encounters with their larger neighbors. Some of the asteroids in our survey could eventually migrate toward Earth."

The Hubble archives represent a newly tapped information resource which could help scientists more precisely estimate the risks the asteroids pose to Earth.

According to Evans and Stapelfeldt, the Hubble archival data also strongly limit the number of small comets that could be passing very near Earth. Last year, Dr. Louis A. Frank of the University of Iowa in Iowa City, using data from NASA's Polar spacecraft, reported he found evidence that about a dozen small comets strike Earth's upper atmosphere each minute. Evans and Stapelfeldt estimate the such small comets should be bright enough to produce thousands of detectable trails in the Hubble archival images, but these were not seen.

The Hubble images capture an asteroid as a long trail produced by its motion across the camera's field of view. The trails appear like the streaks of light found on photos taken at night of speeding cars with their headlights on.

Finding asteroids isn't what the two astronomers originally had in mind. As members of the WFPC2 science team, Evans and Stapelfeldt were examining test images of distant stars and galaxies to ensure that the new camera was functioning properly. These were among the first images taken with WFPC2, which had restored sharp focus to Hubble's images when it was installed in late 1993. Stapelfeldt's wife, Deborah Padgett (also an astronomer), pinpointed the first asteroid in 1994 while looking at images on the couple's home computer. Intrigued, Evans and Stapelfeldt began combing through more than 1,600 of the science team's survey photos, finding 12 more asteroids. This discovery prompted their large-scale search, by eye, of two years worth of Hubble archival images.

Evans' and Stapelfeldt's initial results are reported in the February 1998 issue of the research journal Icarus.

The Space Telescope Science Institute is operated by the Association of Universities for Research in Astronomy, Inc. (AURA) for NASA, under contract with the Goddard Space Flight Center, Greenbelt, MD. The Hubble Space Telescope is a project of international cooperation between NASA and the European Space Agency (ESA).

NOTE TO EDITORS: A photo and caption are available via the World-Wide Web at:

http://oposite.stsci.edu/pubinfo/latest.html orhttp://oposite.stsci.edu/pubinfo/pictures.html


Story Source:

The above story is based on materials provided by National Aeronautics And Space Administration. Note: Materials may be edited for content and length.


Cite This Page:

National Aeronautics And Space Administration. "Astronomers Track Down Asteroids In Hubble Space Telescope Archive." ScienceDaily. ScienceDaily, 10 March 1998. <www.sciencedaily.com/releases/1998/03/980310081620.htm>.
National Aeronautics And Space Administration. (1998, March 10). Astronomers Track Down Asteroids In Hubble Space Telescope Archive. ScienceDaily. Retrieved July 25, 2014 from www.sciencedaily.com/releases/1998/03/980310081620.htm
National Aeronautics And Space Administration. "Astronomers Track Down Asteroids In Hubble Space Telescope Archive." ScienceDaily. www.sciencedaily.com/releases/1998/03/980310081620.htm (accessed July 25, 2014).

Share This




More Space & Time News

Friday, July 25, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Raw: ISS Cargo Ship Launches in Kazakhstan

Raw: ISS Cargo Ship Launches in Kazakhstan

AP (July 23, 2014) The Progress 56 cargo ship launched from the Baikonur Cosmodrome in Kazakhstan Wednesday. NASA says it will deliver cargo and crew supplies to the International Space Station. (July 23) Video provided by AP
Powered by NewsLook.com
Raw: Cargo Craft Undocks from Space Station

Raw: Cargo Craft Undocks from Space Station

AP (July 22, 2014) A Russian Soyuz cargo-carrying spacecraft undocked from the International Space Station on Monday. The craft is due to undergo about ten days of engineering tests before it burns up in the Earth's atmosphere. (July 22) Video provided by AP
Powered by NewsLook.com
NASA Ceremony Honors Moon Walker Neil Armstrong

NASA Ceremony Honors Moon Walker Neil Armstrong

AP (July 21, 2014) NASA honored one of its most famous astronauts Monday by renaming a historic building at the Kennedy Space Center in Florida. It now bears the name of Neil Armstrong, the first man to walk on the moon. (July 21) Video provided by AP
Powered by NewsLook.com
Neil Armstrong's Post-Apollo 11 Life

Neil Armstrong's Post-Apollo 11 Life

Newsy (July 19, 2014) Neil Armstrong gained international fame after becoming the first man to walk on the moon in 1969. But what was his life like after the historic trip? Video provided by Newsy
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:

Breaking News:
from the past week

In Other News

... from NewsDaily.com

Science News

    Health News

      Environment News

        Technology News



          Save/Print:
          Share:

          Free Subscriptions


          Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

          Get Social & Mobile


          Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

          Have Feedback?


          Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
          Mobile: iPhone Android Web
          Follow: Facebook Twitter Google+
          Subscribe: RSS Feeds Email Newsletters
          Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins