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Discovery of Young, Isolated Planetary Mass Objects in the Orionis Star Cluster
M. R. Zapatero
,Osorio,1*V. J. S. Béjar,1E. L. Martín,23R. Rebolo,14D. Barrado
y Navascués,56C. A. L. Bailer-Jones,5R. Mundt5
We present the discovery by optical and near-infrared imaging of an
extremely red, low-luminosity population of isolated objectsin the
young, nearby stellar cluster around the multiple, massivestar Orionis. The proximity (352 parsecs), youth (1 millionto 5 million
years), and low internal extinction make this clusteran ideal site to
explore the substellar domain from the hydrogenmass limit down to a
few Jupiter masses. Optical and near-infraredlow-resolution
spectroscopy of three of these objects confirmsthe very cool spectral
energy distribution (atmospheric effectivetemperatures of 1700 to 2200 kelvin) expected for cluster memberswith masses in the range 5 to 15 times that of Jupiter. Like theplanets of the solar system, these
objects are unable to sustainstable nuclear burning in their
interiors, but in contrast theyare not bound to stars. This new kind
of isolated giant planet,which apparently forms on time scales of less
than a few millionyears, offers a challenge to our understanding of
the formationprocesses of planetary mass objects.
1 Instituto de Astrofísica de Canarias,
E-38200 La Laguna, Tenerife, Spain.
2 Division of
Geological and Planetary Sciences, California Institute of Technology,
MS 150-21, Pasadena, CA 91125, USA.
3 Institute for
Astronomy, University of Hawaii, Honolulu, HI 96822, USA.
4 Consejo Superior de Investigaciones
Científicas (CSIC), Madrid, Spain.
5 Max
Planck Institut für Astronomie, Königstuhl 17, D-69117
Heidelberg, Germany.
6 Universidad Autónoma de
Madrid, E-28049 Madrid, Spain.
*
To whom correspondence should be addressed. E-mail:
mosorio{at}ll.iac.es
Present address: Division of Geological and Planetary
Sciences, California Institute of Technology, Pasadena, CA 91125, USA.
The editors suggest the following Related Resources on Science sites:
In Science Magazine
LETTERS
Mark McCaughrean, Neill Reid, Chris Tinney, Davy Kirkpatrick, Lynne Hillenbrand, Adam Burgasser, John Gizis, Suzanne Hawley;, and Maria Rosa Zapatero Osorio (23 February 2001) Science291 (5508), 1487b.
[DOI: 10.1126/science.291.5508.1487b] |Full Text »
NEWS OF THE WEEK
Robert Irion (6 October 2000) Science290 (5489), 26a.
[DOI: 10.1126/science.290.5489.26a] |Summary »|Full Text »
Orionis Star Cluster
Orionis. The proximity (352 parsecs), youth (1 million to 5 million
years), and low internal extinction make this cluster an ideal site to
explore the substellar domain from the hydrogen mass limit down to a
few Jupiter masses. Optical and near-infrared low-resolution
spectroscopy of three of these objects confirms the very cool spectral
energy distribution (atmospheric effective temperatures of 1700 to 2200 kelvin) expected for cluster members with masses in the range 5 to 15 times that of Jupiter. Like the planets of the solar system, these
objects are unable to sustain stable nuclear burning in their
interiors, but in contrast they are not bound to stars. This new kind
of isolated giant planet, which apparently forms on time scales of less
than a few million years, offers a challenge to our understanding of
the formation processes of planetary mass objects.
