[meteorite-list] Early Results From The Sloan Digital Sky Survey

From: Ron Baalke <baalke_at_meteoritecentral.com>
Date: Thu Apr 22 09:44:11 2004
Message-ID: <200106052309.QAA04017_at_zagami.jpl.nasa.gov>

http://www.sdss.org/news/releases/20010605.edr.html


Sloan Digital Sky Survey

Media Contacts

Michael Turner Steve Koppes
SDSS Scientific Spokesman University of Chicago
773-702-7974 773-702-8366
mturner_at_oddjob.uchicago.edu s-koppes@uchicago.edu

Georgia Whidden Satoru Ikeuchi
Institute for Advanced Study Japan Participation Group
609-734-8239 81-52-789-2427
gwhidden_at_ias.edu ikeuchi@a.phys.nagoya-u.ac.jp

Michael Purdy Hans-Walter Rix
The Johns Hopkins University Max-Planck-Institut für Astronomie
410-516-7906 49-6221-528-210
mcp_at_jhu.edu rix@mpia-hd.mpg.de

Rene Walterbos Barbara Kennedy
Nex Mexico State University Pennsylvania State University
505-646-5990 bkk1_at_psu.edu
rwalterb_at_nmsu.edu

Steve Schultz Vince Stricherz
Princeton University University of Washington
609-258-5729 206-543-2580
sschultz_at_princeton.edu vinces@u.washington.edu

Steven Dick Bruce Gillespie
U.S. Naval Observatory Apache Point Observatory
202-762-0379 505-437-6822
dick.steve_at_usno.navy.mil gillespi@apo.nmsu.edu

Amber Jones Ray Villard
National Science Foundation Space Telescope Science Institute
703-292-8070 410-338-4514
ajones_at_nsf.gov villard@stsci.edu

For release after 9:15 a.m. PDT, June 5, 2001

SDSS 01-01

Early results from the Sloan Digital Sky Survey: From under our nose to the
edge of the universe

Pasadena, Calif. -- Scientists of the Sloan Digital Sky Survey today (June
5) presented results based on early data from the project. The first
glimpses of what will ultimately be the most comprehensive and fully digital
map of the sky included identification of the two most distant objects ever
observed; new light on asteroids; and the first SDSS results on the large-
scale distribution of galaxies.

Sky Survey collaborators also announced the release to the worldwide
astronomy community of the first large piece of the digital sky.

[snip]

Asteroids

The SDSS collaborators presented the first clear evidence for chemical
segregation in the belt of asteroids between Mars and Jupiter.

By viewing the asteroids in five color bands, explained Dr. Tom Quinn
of the University of Washington, the SDSS survey can reliably separate
individual asteroids into two main classes, rocky silicate asteroids and
more primitive carbonaceous asteroids.

"The SDSS observations also showed that the two types of asteroids are
spatially separated," Quinn said, "with the inner belt of rocky asteroids
centered at about 2.8 AU from the sun and the outer belt of carbonaceous
asteroids centered at about 3.2 AU. This distribution has important
implications for unraveling how the solar system formed and suggests that
planet migrations that seem to be common in other planetary systems have
not occurred in ours."

One astronomical unit, or AU, corresponds to the distance from the sun to
the earth.

The SDSS asteroid sample also turned up another surprise.

"There appear to be fewer asteroids smaller than about 4 km in diameter in
the asteroid belt than we previously thought,"  said Dr. Zeljko Ivezic of
Princeton University, the leader of the SDSS asteroid team. "Since the
asteroid belt is believed to be the reservoir for Earth-crossing asteroids,
the new SDSS observations suggest that future asteroid collisions with
Earth may be less likely than previously believed."

The SDSS scanning technique allows only five minutes to follow celestial
objects as they move across the field of view, said Dr. Robert Lupton of
Princeton University. During this time asteroids appear to move a distance
just 1/1000th the size of the moon, relative to the distant stars.

"Nevertheless," Lupton said, "we can reliably detect their tiny motions
and even determine their orbital motions around the sun."

The asteroid observations rely on precision position-finding software
developed by SDSS collaborators at the US Naval Observatory.

Images available:

[snip]

Asteroids:

* Diagram of asteroid belt
  http://www.sdss.org/news/releases/20010605.edr.img7.html
* Graph of asteroid belt cross section
  http://www.sdss.org/news/releases/20010605.edr.img7.html
* Asteroid size distribution
  http://www.sdss.org/news/releases/20010605.edr.img9.html
Received on Tue 05 Jun 2001 07:09:52 PM PDT