SPITZER OBSERVATIONS OF THE {lambda} ORIONIS CLUSTER. II. DISKS AROUND SOLAR-TYPE AND LOW-MASS STARS
- Centro de Investigaciones de AstronomIa, Apdo. Postal 264, Merida 5101-A (Venezuela, Bolivarian Republic of)
- Laboratorio de Astrofisica Estelar y Exoplanetas (LAEX), Centro de Astrobiologia (CAB, INTA-CSIC), LAEFF, P.O. Box 78, E-28691, Villanueva de la canada, Madrid (Spain)
- Department of Astronomy, University of Michigan, 830 Dennison Building, 500 Church Street, Ann Arbor, MI 48109 (United States)
- Space Telescope Science Institute, 3700 San Martin Drive, Baltimore, MD 21218 (United States)
- Five Colleges Astronomy Department, Smith College, Northampton, MA 01027 (United States)
- Center for Exoplanets and Habitable Worlds, The Pennsylvania State University, University Park, PA 16802 (United States)
- Spitzer Science Center, Caltech M/S 220-6, 1200 East California Boulevard, Pasadena, CA 91125 (United States)
We present IRAC/MIPS Spitzer Space Telescope observations of the solar-type and the low-mass stellar population of the young ({approx}5 Myr) {lambda} Orionis cluster. Combining optical and Two Micron All Sky Survey photometry, we identify 436 stars as probable members of the cluster. Given the distance (450 pc) and the age of the cluster, our sample ranges in mass from 2 M{sub sun} to objects below the substellar limit. With the addition of the Spitzer mid-infrared data, we have identified 49 stars bearing disks in the stellar cluster. Using spectral energy distribution slopes, we place objects in several classes: non-excess stars (diskless), stars with optically thick disks, stars with 'evolved disks' (with smaller excesses than optically thick disk systems), and 'transitional disk' candidates (in which the inner disk is partially or fully cleared). The disk fraction depends on the stellar mass, ranging from {approx}6% for K-type stars (R{sub C} - J < 2) to {approx}27% for stars with spectral-type M5 or later (R{sub C} - J>4). We confirm the dependence of disk fraction on stellar mass in this age range found in other studies. Regarding clustering levels, the overall fraction of disks in the {lambda} Orionis cluster is similar to those reported in other stellar groups with ages normally quoted as {approx}5 Myr.
- OSTI ID:
- 21464633
- Journal Information:
- Astrophysical Journal, Vol. 722, Issue 2; Other Information: DOI: 10.1088/0004-637X/722/2/1226; ISSN 0004-637X
- Country of Publication:
- United States
- Language:
- English
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