SIMBAD references

2013ApJ...762L...3B - Astrophys. J., 762, L3 (2013/January-1)

Detection of radio emission from the hyperactive l dwarf 2MASS J13153094-2649513AB.


Abstract (from CDS):

We report the detection of radio emission from the unusually active L5e + T7 binary 2MASS J13153094-2649513AB made with the Australian Telescope Compact Array. Observations at 5.5 GHz reveal an unresolved source with a continuum flux of 370±50 µJy, corresponding to a radio luminosity of Lrad= νLν= (9±3)x1023 erg/s and log10Lrad/Lbol = -5.44±0.22. No detection is made at 9.0 GHz to a 5σ limit of 290 µJy, consistent with a power-law spectrum Sν∝ν–α with α ≳ 0.5. The emission is quiescent, with no evidence of variability or bursts over three hours of observation, and no measurable polarization (V/I < 34%). 2MASS J1315-2649AB is one of the most radio-luminous ultracool dwarfs detected in quiescent emission to date, comparable in strength to other cool sources detected in outburst. Its detection indicates no decline in radio flux through the mid-L dwarfs. It is unique among L dwarfs in having strong and persistent Hα and radio emission, indicating the coexistence of a cool, neutral photosphere (low electron density) and a highly active chromosphere (high electron density and active heating). These traits, coupled with the system's mature age and substellar secondary, make 2MASS J1315-2649AB an important test for proposed radio emission mechanisms in ultracool dwarfs.

Abstract Copyright:

Journal keyword(s): brown dwarfs - stars: chromospheres - stars: individual: 2MASS J13153094-2649513 - stars: low mass - stars: magnetic field

Simbad objects: 19

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