Star formation in the Cometary Globule Ori I-2 - Astrophysics > Astrophysics of GalaxiesReportar como inadecuado

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Abstract: We investigate the young stellar population in and near the cometary globuleOri,I-2. The analysis is based on deep Nordic Optical Telescope R-band andH-alpha images, JCMT SCUBA 450 and 850 micron images combined withnear-infrared 2MASS photometry and mid-infrared archival Spitzer imagesobtained with the IRAC 3.6, 4.5, 5.8 and 8 micron, and MIPS 24 and 70micron instruments. We identify a total of 125 sources within the 5-x5- regionimaged by IRAC. Of these sources 87 are detected in the R-band image and 51 aredetected in the 2MASS survey. The detailed physical properties of the sourcesare explored using a combination of near-mid-infrared color-color diagrams,greybody fitting of SEDs and an online SED fitting tool that uses a library of2D radiation transfer based accretion models of young stellar objects withdisks. Ori I-2 shows clear evidence of triggered star formation with four younglow luminosity pre-main sequence stars embedded in the globule. At least two,possibly as many as four, additional low-mass PMS objects, were discovered inthe field which are probably part of the young sigma-Orionis cluster. Among thePMS stars which have formed in the globule, MIR-54 is a young, deeply embeddedClass 0-I object, MIR-51 and 52 are young Class II sources, while MIR-89 is amore evolved, heavily extincted Class II object with its apparent colorsmimicking a Class 0-I object. The Class II source, MIR-52, which is strong aH-alpha emission line star appears to drive an outflow approximately alignedwith the outflow from MIR-54, and because of the proximity of the two outflows,either star could contribute. MIR-89 appears to excite a low excitation HHobject, HH 992, discovered for the first time in this study.

Autor: B. Mookerjea TIFR, India, G. Sandell SOFIA-USRA, NASA Ames Research Center, USA


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