THE WIDEST-SEPARATION SUBSTELLAR COMPANION CANDIDATE TO A BINARY T TAURI STAR
- Department of Earth and Planetary Science, University of Tokyo, 7-3-1 Hongo, Tokyo 113-0033 (Japan)
- National Astronomical Observatory of Japan, 2-21-1 Osawa, Mitaka, Tokyo 181-8588 (Japan)
- Subaru Telescope, 650 North A'ohoku Place, Hilo, HI 96720 (United States)
- Department of Astronomy, Kyoto University, Kyoto 606-8502 (Japan)
The results of near-infrared imaging and spectroscopy of a substellar companion (SR12 C), with a possible planetary mass, of a binary T Tauri star (SR12 AB) in the {rho} Ophiuchi star-forming region are presented. The object is separated by {approx}8.''7, corresponding to {approx}1100 AU at 125 pc, and has an H-band brightness of 15.2 mag and infrared spectra suggesting a spectral type of M9.0 {+-} 0.5. It is confirmed that SR12 C is physically related to the {rho} Ophiuchi star-forming region from its common proper motion with SR12 AB and its youth is confirmed by a gravity-sensitive spectral feature. Furthermore, based on the number of known members of the {rho} Ophiuchi star-forming region in the area in which SR12 AB exists, the probability of a chance alignment is {approx}1% and it is therefore likely that SR12 C is physically associated with SR12 AB. The mass of SR12 C is estimated by comparing its estimated luminosity and assumed age with the theoretical age-luminosity relation. SR12 C is identified as an extremely low-mass (0.013 {+-} 0.007 M{sub sun}) object, but its separation from its parent star is the widest among planetary-mass companion (PMC) candidates imaged to date. In addition, SR12 C is the first PMC candidate directly imaged around a binary star. This discovery suggests that PMCs form via multiple star formation processes including disk gravitational instability and cloud core fragmentation.
- OSTI ID:
- 21583173
- Journal Information:
- Astronomical Journal (New York, N.Y. Online), Vol. 141, Issue 4; Other Information: DOI: 10.1088/0004-6256/141/4/119; ISSN 1538-3881
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
COSMOLOGY AND ASTRONOMY
ASTROPHYSICS
BRIGHTNESS
GRAVITATION
GRAVITATIONAL INSTABILITY
INFRARED SPECTRA
LUMINOSITY
PROBABILITY
PROPER MOTION
SPECTROSCOPY
T TAURI STARS
BINARY STARS
ERUPTIVE VARIABLE STARS
INSTABILITY
MOTION
OPTICAL PROPERTIES
PHYSICAL PROPERTIES
PHYSICS
PLASMA INSTABILITY
SPECTRA
STARS
VARIABLE STARS