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 sun. 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 〉2 M sun have a disk fraction of ~20%, while lower mass objects (2-0.8 M sun) have a disk fraction of ~50%. This implies that disks around massive stars have a shorter dissipation timescale.
Roccatagliata, V., Bouwman, J., Henning, T., Gennaro, M., Feigelson, E., Kim, J.S., et al. (2011). DISK EVOLUTION IN OB ASSOCIATIONS: DEEPSPITZER/IRAC OBSERVATIONS OF IC 1795. THE ASTROPHYSICAL JOURNAL, 733(2), 113-132 [10.1088/0004-637X/733/2/113].
DISK EVOLUTION IN OB ASSOCIATIONS: DEEPSPITZER/IRAC OBSERVATIONS OF IC 1795
Roccatagliata, Veronica;
2011
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 1 M sun. 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 〉2 M sun have a disk fraction of ~20%, while lower mass objects (2-0.8 M sun) have a disk fraction of ~50%. This implies that disks around massive stars have a shorter dissipation timescale.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
