DEBRIS DISKS IN THE UPPER SCORPIUS OB ASSOCIATION

Journal Article · Tue Nov 10 04:00:00 EST 2009 · Astrophysical Journal

DOI:https://doi.org/10.1088/0004-637X/705/2/1646· OSTI ID:21378245

Carpenter, John M; Hillenbrand, Lynne A ^[1]; Mamajek, Eric E ^[2]; Meyer, Michael R ^[3]

---

1. California Institute of Technology, Department of Astronomy, MC 105-24, Pasadena, CA 91125 (United States)
2. University of Rochester, Department of Physics and Astronomy, Rochester, NY, 14627-0171 (United States)
3. Institute for Astronomy, ETH, CH-8093 Zurich (Switzerland)

We present MIPS 24 mum and 70 mum photometry for 205 members of the Upper Scorpius OB Association. These data are combined with published MIPS photometry for 15 additional association members to assess the frequency of circumstellar disks around 5 Myr old stars with spectral types between B0 and M5. Twelve stars have a detectable 70 mum excess, each of which also has a detectable 24 mum excess. A total of 54 stars are identified with a 24 mum excess more than 32% above the stellar photosphere. The MIPS observations reveal 19 excess sources-8 A/F/G stars and 11 K/M stars-that were not previously identified with an 8 mum or 16 mum excess. The lack of short-wavelength emission and the weak 24 mum excess suggests that these sources are debris systems or the remnants of optically thick primordial disks with inner holes. Despite the wide range of luminosities of the stars hosting apparent debris systems, the excess characteristics are consistent with all stars having dust at similar orbital radii after factoring in variations in the radiation blowout particle size with spectral type. The results for Upper Sco are compared to similar photometric surveys from the literature to re-evaluate the evolution of debris emission. After considering the completeness limits of published surveys and the effects of stellar evolution on the debris luminosity, we find that the magnitude of the 24 mum excess around F-type stars increases between ages of 5 and 17 Myr as found by previous studies, but at approx<2.6sigma confidence. For B7-A9 and G0-K5 stars, any variations in the observed 24 mum excess emission over this age range are significant at less than 2sigma confidence.

• OSTI ID: 21378245
• Journal Information: Astrophysical Journal, Journal Name: Astrophysical Journal Journal Issue: 2 Vol. 705; ISSN ASJOAB; ISSN 0004-637X
• Country of Publication: United States
• Language: English

Related Subjects

79 ASTRONOMY AND ASTROPHYSICS
ATMOSPHERES
DUSTS
EMISSION
EVOLUTION
LUMINOSITY
MATTER
OPTICAL PROPERTIES
PARTICLE SIZE
PHOTOMETRY
PHOTOSPHERE
PHYSICAL PROPERTIES
PROTOPLANETS
SIZE
SOLAR ATMOSPHERE
STAR EVOLUTION
STARS
STELLAR ATMOSPHERES
WAVELENGTHS