2014ApJ...796..127C -
Astrophys. J., 796, 127 (2014/December-1)
A deep Spitzer survey of circumstellar disks in the young double cluster, h and χ Persei.
CLOUTIER R., CURRIE T., RIEKE G.H., KENYON S.J., BALOG Z. and JAYAWARDHANA R.
Abstract (from CDS):
We analyze very deep Infrared Array Camera and Multiband Imaging Photometer for Spitzer (MIPS) photometry of ∼12, 500 members of the 14 Myr old Double Cluster, h and χ Persei, building upon our earlier, shallower Spitzer Cycle 1 studies. Numerous likely members show infrared (IR) excesses at 8 µm and 24 µm, indicative of circumstellar dust. The frequency of stars with 8 µm excess is at least 2% for our entire sample, slightly lower (higher) for B/A stars (later type, lower mass stars). Optical spectroscopy also identifies gas in about 2% of systems, but with no clear trend between the presence of dust and gas. Spectral energy distribution modeling of 18 sources with detections at optical wavelengths through MIPS 24 µm reveals a diverse set of disk evolutionary states, including a high fraction of transitional disks, though similar data for all disk-bearing members would provide constraints. Using Monte Carlo simulations, we combine our results with those for other young clusters to study the global evolution of dust/gas disks. For nominal cluster ages, the e-folding times (τ0) for the frequency of warm dust and gas are 2.75 Myr and 1.75 Myr, respectively. Assuming a revised set of ages for some clusters, these timescales increase to 5.75 and 3.75 Myr, respectively, implying a significantly longer typical protoplanetary disk lifetime than previously thought. In both cases, the transitional disk duration, averaged over multiple evolutionary pathways, is ~1 Myr. Finally, 24 µm excess frequencies for 4-6 M☉ stars appear lower than for 1-2.5 M☉stars in other 10-30 Myr old clusters.
Abstract Copyright:
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Journal keyword(s):
circumstellar matter - open clusters and associations: individual: (NGC 869, NGC 884) - planetary systems - protoplanetary disks - stars: formation
VizieR on-line data:
<Available at CDS (J/ApJ/796/127): table1.dat, table2.dat, table4.dat>
Nomenclature:
Table 1: [CCR2014] NNNNN (Nos 1-13956).
Simbad objects:
13968
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