SCExAO and GPI Y JHBand Photometry and Integral Field Spectroscopy of the Young Brown Dwarf Companion to HD 1160

E. Victor Garcia, Thayne Currie, Olivier Guyon, Keivan G. Stassun, Nemanja Jovanovic, Julien Lozi, Tomoyuki Kudo, Danielle Doughty, Josh Schlieder, J. Kwon, T. Uyama, M. Kuzuhara, J. C. Carson, T. Nakagawa, J. Hashimoto, N. Kusakabe, L. Abe, W. Brandner, T. D. Brandt, M. Feldt, M. Goto, C. A. Grady, Y. Hayano, M. Hayashi, S. S. Hayashi, T. Henning, K. W. Hodapp, M. Ishii, M. Iye, M. Janson, R. Kandori, G. R. Knapp, T. Matsuo, M. W. McElwain, S. Miyama, J.-I. Morino, A. Moro-Martin, T. Nishimura, T.-S. Pyo, E. Serabyn, T. Suenaga, H. Suto, R. Suzuki, Y. H. Takahashi, H. Takami, M. Takami, N. Takato, H. Terada, C. Thalmann, E. L. Turner, M. Watanabe, J. Wisniewski, T. Yamada, T. Usuda, M. Tamura

We present high signal-to-noise ratio, precise Y JH photometry and Y band (0.957-1.120 μm) spectroscopy of HD 1160 B, a young substellar companion discovered from the Gemini NICI Planet Finding Campaign using the Subaru Coronagraphic Extreme Adaptive Optics instrument and the Gemini Planet Imager. HD 1160 B has typical mid-M dwarf-like infrared colors and a spectral type of M5.5{}-0.5+1.0, where the blue edge of our Y band spectrum rules out earlier spectral types. Atmospheric modeling suggests HD 1160 B has an effective temperature of 3000-3100 K, a surface gravity of log g = 4-4.5, a radius of 1.55 ± 0.10 RJ, and a luminosity of log L/L⊙ = -2.76 ± 0.05. Neither the primary’s Hertzspring-Russell diagram position nor atmospheric modeling of HD 1160 B show evidence for a subsolar metallicity. Interpretation of the HD 1160 B spectroscopy depends on which stellar system components are used to estimate the age. Considering HD 1160 A, B and C jointly, we derive an age of 80-125 Myr, implying that HD 1160 B straddles the hydrogen-burning limit (70-90 MJ). If we consider HD 1160 A alone, younger ages (20-125 Myr) and a brown dwarf-like mass (35-90 MJ) are possible. Interferometric measurements of the primary, a precise Gaia parallax, and moderate-resolution spectroscopy can better constrain the system’s age and how HD 1160 B fits within the context of (sub)stellar evolution.

The Astrophysical Journal

American Astronomical Society

834

2

162

10.3847/1538-4357/834/2/162