IRAS04325+2402C: A very low mass object with an edge-on disk

Abstract

IRAS04325+2402C is a low luminosity object located near a protostar in Taurus. We present new spatially-resolved mm observations, near-infrared spectroscopy, and Spitzer photometry that improve the constraints on the nature of this source. The object is clearly detected in our 1.3 mm interferometry map, allowing us to estimate the mass in a localized disk+envelope around it to be in the range of 0.001 to 0.01Ms. Thus IRAS04325C is unlikely to accrete significantly more mass. The near-infrared spectrum cannot be explained with an extincted photosphere alone, but is consistent with a 0.03-0.1Ms central source plus moderate veiling, seen in scattered light, confirming the edge-on nature of the disk. Based on K-band flux and spectral slope we conclude that a central object mass >~0.1Ms is unlikely. Our comparison of the full spectral energy distribution, including new Spitzer photometry, with radiative transfer models confirms the high inclination of the disk (>~80deg), the very low mass of the central source, and the small amount of circumstellar material. IRAS04325C is one of the lowest mass objects with a resolved edge-on disk known to date, possibly a young brown dwarf, and a likely wide companion to a more massive star. With these combined properties, it represents a unique case to study the formation and early evolution of very low mass objects.