Brown Dwarf Companions to G-Type Stars. I. Gliese 417B and Gliese 584C
Abstract
We present astrometric and spectroscopic observations confirming that two nearby G dwarf systems (Gliese 417 = BD+36°2162 and Gliese 584AB = η CrB AB) have a widely separated, L dwarf, substellar companion. Using age estimates of the G dwarf primaries, we estimate masses for these L dwarfs from theoretical evolutionary tracks. For the L4.5 dwarf Gl 417B we estimate an age of 0.08–0.3 Gyr and a mass of 0.035 ± 0.015 M_⊙. For the L8 dwarf Gl 584C we estimate an age of 1.0–2.5 Gyr and a mass of 0.060 ± 0.015 M_⊙. This latter object also shows evidence of spectrum variability, which may be due to surface inhomogeneities rotating into and out of view. These new companions are also compared to six other L dwarf and T dwarf companions previously recognized. For the L dwarf companions, ages implied by the presence or absence of lithium are consistent with ages inferred from the primaries alone.
Additional Information
© 2001. The American Astronomical Society. Received 2000 December 26; accepted 2001 March 12. J. D. K. acknowledges the support of the Jet Propulsion Laboratory, California Institute of Technology, which is operated under contract with the National Aeronautics and Space Administration. We thank Joel Aycock, Wayne Wack, and Barbara Schaefer for the outstanding job they did in obtaining the Keck LRIS service observations on 1999 March 31; Alice Monet and Steve Levine for obtaining some of the astrometric data (Table 1) used for common proper motion verification; John Stauffer and Dave Soderblom for enlightening discussions; and Lynne Hillenbrand and John Carpenter for acquiring data in 2000 December used in the telluric absorption discussion of § 3.3. I. N. R. and J. L. acknowledge funding through a NASA/JPL grant to 2MASS Core Project science. The finder charts of Figure 1 make use of the Digitized Sky Survey, which was produced at the Space Telescope Science Institute under US Government grant NAGW-2166. Research in this paper has also relied partly on photographic plates obtained at the Palomar Observatory 48 inch Oschin Telescope for the Second Palomar Observatory Sky Survey which was funded by the Eastman Kodak Company, the National Geographic Society, the Samuel Oschin Foundation, the Alfred Sloan Foundation, the National Science Foundation grants AST84-08225, AST87-19465, AST90-23115, and AST93-18984, and the National Aeronautics and Space Administration grants NGL 05002140 and NAGW 1710. This research has also made use of the SIMBAD database, operated at CDS, Strasbourg, France. This publication makes use of data from the Two Micron All Sky Survey, which is a joint project of the University of Massachusetts and the Infrared Processing and Analysis Center, funded by the National Aeronautics and Space Administration and the National Science Foundation.Attached Files
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Additional details
- Eprint ID
- 75995
- Resolver ID
- CaltechAUTHORS:20170408-144254817
- NASA/JPL/Caltech
- NASA
- NAGW-2166
- Eastman Kodak Company
- National Geographic Society
- Samuel Oschin Foundation
- Alfred P. Sloan Foundation
- NSF
- AST84-08225
- NSF
- AST87-19465
- NSF
- AST90-23115
- NSF
- AST93-18984
- NASA
- NGL 05002140
- NASA
- NAGW 1710
- Created
-
2017-05-02Created from EPrint's datestamp field
- Updated
-
2021-11-15Created from EPrint's last_modified field
- Caltech groups
- Infrared Processing and Analysis Center (IPAC)