The Planetary Mass Companion 2MASS1207-3932 B: Temperature, Mass and Evidence for an Edge-On Disk

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dc.creatorMohanty, Subhanjoy
dc.creatorJayawardhana, Ray
dc.creatorHuelamo, Nuria
dc.creatorMamajek, Eric
dc.date2006-10-18
dc.date.accessioned2026-07-07T10:23:55Z
dc.date.available2026-07-07T10:23:55Z
dc.descriptionWe present J-band imaging and H+K-band low-resolution spectroscopy of 2MASS1207-3932 AB, obtained with VLT NACO. For the putative planetary mass secondary, we find J = 20.0+/-0.2 mag. The HK spectra of both components imply low gravity, and a dusty atmosphere for the secondary. Comparisons to synthetic spectra yield Teff_A ~ 2550+/-150K, and Teff_B ~ 1600+/-100K, consistent with their late-M and mid-to-late L types. For these Teff, and an age of 5-10 Myrs, evolutionary models imply M_A ~ 24+/-6 M_Jup and M_B ~ 8+/-2 M_Jup. Independent comparisons of these models to the observed colors, spanning ~I to L', also yield the same masses and temperatures. Our primary mass agrees with other recent analyses; however, our secondary mass, while still in the planetary regime, is 2-3 times larger than claimed previously. This discrepancy can be traced to the luminosities: while the absolute photometry and Mbol of the primary agree with theoretical predictions, the secondary is ~ 2.5+/-0.5 mag fainter than expected in all bands from I to L' and in Mbol. This accounts for the much lower secondary mass (and temperature) derived earlier. We argue that this effect is highly unlikely to result from a variety of model-related problems, and is instead real. This conclusion is bolstered by the absence of any luminosity problems in either the primary, or in AB Pic B which we also analyse. We therefore suggest grey extinction in 2M1207B, due to occlusion by an edge-on circum-secondary disk. This is consistent with the observed properties of edge-on disks around T Tauri stars, and with the known presence of a high-inclination evolved disk around the primary. Finally, the system's implied mass ratio of ~0.3 suggests a binary-like formation scenario. (abridged)
dc.descriptionAccepted by The Astrophysical Journal, 43 pages text + 16 figs + 1 table
dc.identifierhttps://arxiv.org/abs/astro-ph/0610550
dc.identifierhttp://arxiv.org/abs/astro-ph/0610550
dc.identifierAstrophys.J.657:1064-1091,2007
dc.identifierdoi:10.1086/510877
dc.identifier.urihttp://salesiana.dossiersoluciones.com/handle/123456789/176009
dc.subjectAstrophysics
dc.titleThe Planetary Mass Companion 2MASS1207-3932 B: Temperature, Mass and Evidence for an Edge-On Disk
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