[meteorite-list] Tightening the (Asteroid) Belt around Zeta Leporis

From: Ron Baalke <baalke_at_meteoritecentral.com>
Date: Sun, 28 Jan 2007 18:44:03 -0800 (PST)
Message-ID: <200701290244.SAA27130_at_zagami.jpl.nasa.gov>

Gemini Observatory
Hilo, Hawaii

19 January 2007

Tightening the (Asteroid) Belt around Zeta Leporis

New mid-infrared images of the Zeta Leporis circumstellar disk obtained with
T-ReCS on Gemini South have for the first time revealed what researchers are
calling an "exo-asteroid belt" around another star. Far from a passive dust
disk, the new data shows that there must be some sort of ongoing collisional
activity within a few astronomical units (AU) of the star. These collisions
sustain the replenishment of the small dust grains detected in the T-ReCS
images. The results also lend support to the theory that the Zeta Leporis
system contains a large reservoir of asteroid-sized bodies as well as the
possibility of rocky planets.

The team, lead by University of Florida Ph.D. student Margaret Moerchen and
her advisor Charles Telesco, observed Zeta Leporis as part of a broader
research program centered on the search for resolved circumstellar disks.
The Gemini observations supplement previous observations made in 2001 that
placed a strong limit on the size of the disk, but did not resolve the dust
emission from that of the central star.

The team using Gemini, which included UF researchers Chris Packham and Tom
Kehoe, found that the majority of the dust grains in the system reside
within 3 AU from the central star, exactly where the asteroids orbit in our
own Solar system. The fact that the dust emission comes from so close to the
central star makes this type of observation very difficult to carry out. It
is the combination of the excellent mid-IR performance of Gemini South and
the ingenuity of the researchers that makes this type of discovery possible.

The result will appear in an upcoming issue of ApJL and was featured in the
January 8, 2007 issue of ScienceNews. In the ScienceNews article Charles
Beichman of NASA's JPL says, "The high angular resolution measurement of the
Zeta Leporis disk is a very exciting result. We now have direct evidence for
structures around other stars that are directly analogous to the asteroid
belt in our solar system."

A pre-print of this paper can be found on astro-ph at
     http://arxiv.org/abs/astro-ph/0612550

Gemini is an international partnership managed by the Association of
Universities for Research in Astronomy under a cooperative agreement with
the National Science Foundation.

The Gemini Observatory provides the astronomical communities in each partner
country with state-of-the-art astronomical facilities that allocate
observing time in proportion to each country's contribution. in addition to
financial support, each country also contributes significant scientific and
technical resources. The national research agencies that form the Gemini
partnership include: the US National Science Foundation (NSF), the UK
Particle Physics and Astronomy Research Council (PPARC), the Canadian
National Research Council (NRC), the Chilean Comisi Nacional de investigaci
Cientifica y Tecnolica (CONiCYT), the Australian Research Council (ARC), the
Argentinean Consejo Nacional de investigaciones Cienticas y Tnicas (CONiCET)
and the Brazilian Conselho Nacional de Desenvolvimento Cientico e Tecnolico
(CNPq). The Observatory is managed by the Association of Universities for
Research in Astronomy, inc. (AURA) under a cooperative agreement with the
NSF. The NSF also serves as the executive agency for the international
partnership.

[NOTE: Images supporting this release are available at
http://www.gemini.edu/index.php?option=content&task=view&id=222 ]
Received on Sun 28 Jan 2007 09:44:03 PM PST