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Description
This table contains results from a survey of the Orion A and B molecular clouds undertaken with the IRAC and MIPS instruments on board Spitzer. In total, five distinct fields were mapped, covering 9 deg<sup>2</sup> in five mid-IR bands spanning 3 - 24 microns (µm). The survey includes the Orion Nebula Cluster, the Lynds 1641, 1630, and 1622 dark clouds, and the NGC 2023, 2024, 2068, and 2071 nebulae. These data are merged with the Two Micron All Sky Survey point source catalog to generate a catalog of eight-band photometry. The authors identify 3479 dusty young stellar objects (YSOs) in the Orion molecular clouds by searching for point sources with mid-IR colors indicative of reprocessed light from dusty disks or in-falling envelopes. The YSOs are subsequently classified on the basis of their mid-IR colors and their spatial distributions are presented. The authors classify 2991 of the YSOs as pre-main-sequence stars with disks and 488 as likely protostars. Most of the sources were observed with IRAC in two to three epochs over six months; the authors search for variability between the epochs by looking for correlated variability in the 3.6 and 4.5 um bands. They find that 50% of the dusty YSOs show variability. The variations are typically small (~ 0.2 mag) with the protostars showing a higher incidence of variability and larger variations. The observed correlations between the 3.6, 4.5, 5.8, and 8 um variability suggests that we are observing variations in the heating of the inner disk due to changes in the accretion luminosity or rotating accretion hot spots. This table was created by the HEASARC in January 2013 based on an electronic version of Table 4 from the reference paper which was obtained from the AJ web site. This is a service provided by NASA HEASARC .
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