POSTER PAPER 4.04
A Large Area Variability Survey in Orion OB1:
Digging into the Fossil Record of Low-mass Star Formation
Cesar Briceno, A. Katherina Vivas, Nuria Calvet and Lee Hartmann
Institute: Centro de Investigaciones de Astronomia (CIDA)
Institute: Astronomy Department, Yale University
Institute: Smithsonian Astrophysical Observatory
Contact Email: briceno@cida.ve
Abstract:
In an area of ~ 25 square degrees we have unveiled new populations of low-mass
young stars, from young (~ 2 Myr) regions in
dense molecular clouds like Orion OB 1b, to older (~ 10 Myr) areas
devoid of gas and dust like the sparse OB 1a subassociation.
The newly identified young stars are spatially coincident with
the high mass O, B and A stars, indicating that little, if any, mass
segregation has occured. The absence of dust and gas in Ori OB 1a
suggests that star formation is a rapid process,
and that molecular clouds do not last more than a few million years
after the first stars are born.
The lack of accretion indicators or near IR emission from inner dusty
disks in Ori OB 1a region suggests that significant
disk dissipation has occured in a few Myr, possibly due to the
coagulation/agglomeration of dust particles into larger bodies like
planetesimals or planets.
Index Keywords: Star Formation; Young Stars; Variability; Photometry
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Manuscript submitted: 2001-Nov-25
"The Future of Cool-Star Astrophysics", 2003, Eds. A. Brown,
G. M. Harper, & T. R. Ayres.
Proceedings of 12th Cambridge Workshop on Cool Stars, Stellar Systems,
& The Sun,
© 2003 University of Colorado.