Herschel PACS and SPIRE Observations of TWA brown dwarf discs

Abstract

We present Herschel SPIRE observations for the TW Hydrae association (TWA) brown dwarf discs SSSPM J1102-3431 (SS1102) and 2MASSW J1207334-393254 (2M1207). Both discs are undetected in the SPIRE 200-500mu bands. We have also analyzed the archival PACS data and find no detection for either source in the 160mu band. Based on radiative transfer modeling, we estimate an upper limit to the disc mass for both sources of 0.1 M_Jup. The lack of detection in the SPIRE bands could be due to a paucity of millimeter sized dust grains in the 2M1207 and SS1102 discs. We also report a non-detection for the brown dwarf 2MASS J1139511-315921 (2M1139) in the PACS 70 and 160mu bands. We have argued for the presence of a warm debris disc around 2M1139, based on an excess emission observed at 24mu. The mid-infrared colors for 2M1139 are similar to the transition discs in the Taurus and Ophuichus regions. A comparison of the brown dwarf disc masses over a ~1-10 Myr age interval suggests a decline in the disc mass with the age of the system.

Accepted in A&A

References in corpus (14)

• Herschel Space Observatory - An ESA facility for far-infrared and submillimetre astronomy
• The Photodetector Array Camera and Spectrometer (PACS) on the Herschel Space Observatory
• The Herschel-SPIRE instrument and its in-flight performance
• Exploring brown dwarf disks: A 1.3 mm survey in Taurus
• A Theoretical Interpretation of the Black Hole Fundamental Plane
• The Nature of Transition Circumstellar Disks III. Perseus, Taurus, and Auriga
• The stellar mass-accretion rate relation in T Tauri stars and brown dwarfs
• Emission Line Variability of the Accreting Young Brown Dwarf 2MASSW J1207334-393254: From Hours to Years
• The Trigonometric Parallax of the Brown Dwarf Planetary System 2MASSW J1207334-393254
• Disc Frequencies for Brown Dwarfs in the Upper Scorpius OB Association: Implications for Brown Dwarf Formation Theories
• New Brown Dwarf Disks in the TW Hydrae Association
• A Herschel Search For Cold Dust in Brown Dwarf Disks: First Results
• Protoplanetary Disk Masses in IC348: A Rapid Decline in the Population of Small Dust Grains After 1 Myr
• Revised analysis of SPIRE observations for 2M1207

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• A WISE-based search for debris discs amongst M-dwarfs in nearby, young, moving groups
• Herschel survey of brown dwarf disks in Rho Ophiuchi
• A homogeneous analysis of disks around brown dwarfs