HUBBLE SPACE TELESCOPE IMAGING AND SPECTRAL ANALYSIS OF TWO BROWN DWARF BINARIES AT THE L DWARF/T DWARF TRANSITION
- Center for Astrophysics and Space Science, University of California San Diego, La Jolla, CA 92093 (United States)
- Massachusetts Institute of Technology, Kavli Institute for Astrophysics and Space Research, 77 Massachusetts Avenue, Cambridge, MA 02139 (United States)
We present a detailed examination of the brown dwarf multiples 2MASS J08503593+1057156 and 2MASS J17281150+3948593, both suspected of harboring components that straddle the L dwarf/T dwarf transition. Resolved photometry from Hubble Space Telescope/NICMOS shows opposite trends in the relative colors of the components, with the secondary of 2MASS J0850+1057 being redder than its primary, while that of 2MASS J1728+3948 is bluer. We determine near-infrared component types by matching combined-light, near-infrared spectral data to binary templates, with component spectra scaled to resolved NICMOS and K{sub p} photometry. Combinations of L7 + L6 for 2MASS J0850+1057 and L5 + L6.5 for 2MASS J1728+3948 are inferred. Remarkably, the primary of 2MASS J0850+1057 appears to have a later-type classification compared to its secondary, despite being 0.8-1.2 mag brighter in the near-infrared, while the primary of 2MASS J1728+3948 is unusually early for its combined-light optical classification. Comparison to absolute magnitude/spectral type trends also distinguishes these components, with 2MASS J0850+1057A being {approx}1 mag brighter and 2MASS J1728+3948A {approx} 0.5 mag fainter than equivalently classified field counterparts. We deduce that thick condensate clouds are likely responsible for the unusual properties of 2MASS J1728+3948A, while 2MASS J0850+1057A is either an inflated young brown dwarf or a tight unresolved binary, making it potentially part of a wide, low-mass, hierarchical quintuple system.
- OSTI ID:
- 21583225
- Journal Information:
- Astronomical Journal (New York, N.Y. Online), Vol. 141, Issue 3; Other Information: DOI: 10.1088/0004-6256/141/3/70; ISSN 1538-3881
- Country of Publication:
- United States
- Language:
- English
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