A Young Brown Dwarf Companion to DH Tauri Itoh, Yoichi; Hayashi, Masahiko; Tamura, Motohide ...
Astrophysical journal/The Astrophysical journal,
02/2005, Letnik:
620, Številka:
2
Journal Article
Recenzirano
Odprti dostop
We present the detection of a young brown dwarf companion, DH Tau B, associated with the classical T Tauri star DH Tau. Near-infrared coronagraphic observations with CIAO on the Subaru Telescope have ...revealed DH Tau B with H = 15 mag located 2 3 (330 AU) away from the primary, DH Tau A. Comparing its position with a Hubble Space Telescope archive image, we confirmed that DH Tau A and B share a common proper motion, suggesting that they are physically associated with each other. The near-infrared color of DH Tau B is consistent with those of young stellar objects. The near-infrared spectra of DH Tau B show deep water absorption bands, a strong K I absorption line, and a moderate Na I absorption line. We derived its effective temperature and surface gravity of T sub(eff) = 2700 2800 K and log g = 4.0 4.5, respectively, by comparing the observed spectra with synthesized spectra of low-mass objects. The location of DH Tau B on the H-R diagram gives its mass of 30M sub(J) 50M sub(J).
A Common Proper Motion Stellar Companion to HAT-P-7 Narita, Norio; Takahashi, Yasuhiro H; Kuzuhara, Masayuki ...
Publications of the Astronomical Society of Japan,
12/2012, Letnik:
64, Številka:
6
Journal Article
Recenzirano
Odprti dostop
We report that HAT-P-7 has a common proper motion stellar companion. The companion is located at
$ \sim$
3
$ .\!\!\!''$
9 to the east and estimated to be an M5.5V dwarf based on its colors. We also ...confirm the presence of a third companion, which was first reported by Winn et al. (2009, ApJ, 703, L99), based on long-term radial velocity measurements. We revisit the migration mechanism of HAT-P-7b given to the presence of those companions, and propose the sequential Kozai migration as a likely scenario in this system. This scenario may explain the reason for an outlier in the discussion of the spin-orbit alignment timescale for HAT-P-7b by Albrecht et al. (2012, ApJ, 757, 18).
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