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

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

Abstract

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 1M(circle dot). 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 3-5 Myr. 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 >2M(circle dot) have a disk fraction of similar to 20%, while lower mass objects (2-0.8M(circle dot)) have a disk fraction of similar to 50%. This implies that disks around massive stars have a shorter dissipation timescale.

Original languageEnglish
Article number113
Number of pages20
JournalAstrophysical Journal
Volume733
Issue number2
DOIs
Publication statusPublished - 1 Jun 2011

Keywords

  • ISM: individual objects (W3)
  • open clusters and associations: individual (W3 IC1795)
  • protoplanetary disks
  • stars: formation
  • stars: pre-main sequence
  • X-rays: stars
  • ORION-NEBULA-CLUSTER
  • STAR-FORMING REGION
  • ETA-CHAMAELEONTIS CLUSTER
  • INFRARED ARRAY CAMERA
  • MAIN-SEQUENCE STARS
  • YOUNG STELLAR CLUSTER
  • INITIAL MASS FUNCTION
  • SPACE-TELESCOPE
  • CIRCUMSTELLAR DISKS
  • PROTOPLANETARY DISK

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