Disk evolution in ob associations: Deep Spitzer/IRAC observations of IC 1795

Veronica Roccatagliata, Jeroen Bouwman, Thomas Henning, Mario Gennaro, Eric Feigelson, Jinyoung Serena Kim, Aurora Sicilia-Aguilar, Warrick A. Lawson

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38 Scopus citations


We present a deep Spitzer/Infrared Array Camera (IRAC) survey of the OB association IC 1795 carried out to investigate the evolution of protoplanetary disks in regions of massive star formation. Combining Spitzer/IRAC data with Chandra/Advanced CCD Imaging Spectrometer observations, we find 289 cluster members. An additional 340 sources with an infrared excess, but without X-ray counterpart, are classified as cluster member candidates. Both surveys are complete down to stellar masses of about 1 M. We present pre-main-sequence isochrones computed for the first time in the Spitzer/IRAC colors. The age of the cluster, determined via the location of the Class III sources in the [3.6]-[4.5]/[3.6] color-magnitude diagram, is in the range of 3-5Myr. As theoretically expected, we do not find any systematic variation in the spatial distribution of disks within 0.6 pc of either O-type star in the association. However, the disk fraction in IC 1795 does depend on the stellar mass: sources with masses >2 M have a disk fraction of ∼ 20%, while lower mass objects (2-0.8 M) have a disk fraction of ∼ 50%. This implies that disks around massive stars have a shorter dissipation timescale.

Original languageEnglish (US)
Article number113
JournalAstrophysical Journal
Issue number2
StatePublished - Jun 1 2011

All Science Journal Classification (ASJC) codes

  • Astronomy and Astrophysics
  • Space and Planetary Science


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