THE SPITZER SPACE TELESCOPE SURVEY OF THE ORION A AND B MOLECULAR CLOUDS. I. A CENSUS OF DUSTY YOUNG STELLAR OBJECTS AND A STUDY OF THEIR MID-INFRARED VARIABILITY

By S. Megeath, R. Gutermuth, J. Muzerolle, E. Kryukova, K. Flaherty, J. Hora, L. Allen, L. Hartmann, P. Myers, J. Pipher and 3 more. 2012

329 citations recorded by the source corpus.

We present 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 deg2 in five mid-IR bands spanning 3–24 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. We 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 infalling envelopes. The YSOs are subsequently classified on the basis of their mid-IR colors and their spatial distributions are presented. We 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; we search for variability between the epochs by looking for correlated variability in the 3.6 and 4.5 μm bands. We 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 μm 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.

Subfields: Astronomy and Astrophysics

View Paper: https://www.semanticscholar.org/paper/8998192eb0cc16149141debce298e372267fc82e

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Citations in the corpus

YOUNG STELLAR OBJECTS IN THE GOULD BELT (2015, background): “The only two exceptions are the Taurus and Orion Molecular Clouds, both of which are so large they were the subject of their own, dedicated surveys by different teams (Rebull et al. 2010; Megeath et al. 2012).”
Dust Evolution and the Formation of Planetesimals (2016, background): “…with ages from 1Myr to tens of Myrs have been surveyed by various projects with Spitzer (e.g. Allen et al. 2004; Megeath et al. 2004; Luhman 2007; Evans et al. 2009; Gutermuth et al. 2009; Fang et al. 2009; Luhman et al. 2010; Megeath et al. 2012; Fang et al. 2013; Sicilia-Aguilar et al. 2015).”
The APOGEE-2 Survey of the Orion Star-forming Complex. II. Six-dimensional Structure (2018, methodology): “From 7 Class II stars that have been identified by Megeath et al. (2012) as YSOs in L1622, we measure average astrometric parameters of π = 2.871± 0.026 mas (d = 345±5.5 pc), vα = 5.343± 0.045 mas yr−1, and vα = 4.271 ± 0.040 mas yr−1.”
ON THE STAR FORMATION EFFICIENCY OF TURBULENT MAGNETIZED CLOUDS (2012, background): “In a recent survey of Orion A+B, Megeath et al. (2012) indeed detected 3479 YSOs.”
THE HERSCHEL ORION PROTOSTAR SURVEY: SPECTRAL ENERGY DISTRIBUTIONS AND FITS USING A GRID OF PROTOSTELLAR MODELS (2016, methodology): “HOPS 105 lies 8.7′′ to the north of an infrared-bright source, identified by Megeath et al. (2012) as a young star with a protoplanetary disk.”
An ALMA study of the Orion Integral Filament: I. Evidence for narrow fibers in a massive cloud (2018, background): “A census of its embedded stellar population at IR (Megeath et al. 2012; Stutz et al. 2013; Furlan et al. 2016), X-ray (Getman et al. 2005; Rivilla et al. 2013), centimeter (Kounkel et al. 2014; Forbrich et al. 2016), and millimeter (Takahashi et al. 2013; Teixeira et al. 2016; Kainulainen et al.…”