PROTOPLANETARY AND TRANSITIONAL DISKS IN THE OPEN STELLAR CLUSTER IC 2395
- Max Planck Institute for Astronomy, Heidelberg, D-69117 (Germany)
- NASA Exoplanet Exploration Program, Jet Propulsion Laboratory, California Institute of Technology, 4800 Oak Grove Drive, Pasadena, CA 91109 (United States)
- Steward Observatory, 933 N. Cherry Ave, University of Arizona, Tucson, AZ 85721 (United States)
- Konkoly Observatory, Research Center for Astronomy and Earth Sciences, P.O. Box 67, H-1525 Budapest (Hungary)
- Space Telescope Science Institute, 3700 San Martin Drive, Baltimore, MD 21218 (United States)
- Department of Astronomy, University of Massachusetts, Amherst, MA (United States)
- Institute for Astronomy, ETH Zürich, Wolfgang-Pauli-Strasse 27, 8093, Zürich (Switzerland)
- Dept. of Optics and Quantum Electronics, University of Szeged, H-6720 Szeged (Hungary)
We present new deep UBVRI images and high-resolution multi-object optical spectroscopy of the young (∼6–10 Myr old), relatively nearby (800 pc) open cluster IC 2395. We identify nearly 300 cluster members and use the photometry to estimate their spectral types, which extend from early B to middle M. We also present an infrared imaging survey of the central region using the IRAC and MIPS instruments on board the Spitzer Space Telescope , covering the wavelength range from 3.6 to 24 μ m. Our infrared observations allow us to detect dust in circumstellar disks originating over a typical range of radii from ∼0.1 to ∼10 au from the central star. We identify 18 Class II, 8 transitional disk, and 23 debris disk candidates, respectively, 6.5%, 2.9%, and 8.3% of the cluster members with appropriate data. We apply the same criteria for transitional disk identification to 19 other stellar clusters and associations spanning ages from ∼1 to ∼18 Myr. We find that the number of disks in the transitional phase as a fraction of the total with strong 24 μ m excesses ([8] – [24] ≥ 1.5) increases from (8.4 ± 1.3)% at ∼3 Myr to (46 ± 5)% at ∼10 Myr. Alternative definitions of transitional disks will yield different percentages but should show the same trend.
- OSTI ID:
- 22667159
- Journal Information:
- Astrophysical Journal, Vol. 832, Issue 1; Other Information: Country of input: International Atomic Energy Agency (IAEA); ISSN 0004-637X
- Country of Publication:
- United States
- Language:
- English
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