Deep Near-Infrared Imaging of the rho Oph Cloud Core: Clues to the Origin of the Lowest-Mass Brown Dwarfs - Astrophysics > Solar and Stellar AstrophysicsReport as inadecuate




Deep Near-Infrared Imaging of the rho Oph Cloud Core: Clues to the Origin of the Lowest-Mass Brown Dwarfs - Astrophysics > Solar and Stellar Astrophysics - Download this document for free, or read online. Document in PDF available to download.

Abstract: A search for young substellar objects in the rho Oph cloud core region hasbeen made using the deep-integration Combined Calibration Scan images of the2MASS extended mission in J, H and Ks bands, and Spitzer IRAC images at 3.6,4.5, 5.8 and 8.0 microns. The field of view of the combined observations was 1deg x 9.3 arcmin, and the 5 sigma limiting magnitude at J was 20.5. Comparisonof the observed SEDs with the predictions of the COND and DUSTY models, for anassumed age of 1 Myr, supports the identification of many of the sources withbrown dwarfs, and enables the estimation of effective temperature, Teff. Thecluster members are then readily distinguishable from background stars by theirlocations on a plot of flux density versus Teff. The range of estimated Teffextends down to ~ 750 K, suggesting the presence of objects of sub-Jupitermass. The results also suggest that the mass function for the rho Oph cloudresembles that of the sigma Orionis cluster based on a recent study, with bothrising towards lower masses. The other main result from our study is theapparent presence of a progressive blueward skew in the distribution of J-H andH-Ks colors, such that the blue end of the range becomes increasingly bluerwith increasing magnitude. We suggest that this behavior might be understood interms of the -ejected stellar embryo- hypothesis, whereby some of thelowest-mass brown dwarfs could escape to locations close to the front edge ofthe cloud, and thereby be seen with less extinction.



Author: Kenneth A. Marsh, Peter Plavchan, J. Davy Kirkpatrick, Patrick J. Lowrance, Roc M. Cutri, Thangasamy Velusamy

Source: https://arxiv.org/







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