Spectroscopic characterization of HD 95086 b with the Gemini Planet Imager

Journal Article · 21 June 2016 · The Astrophysical Journal (Online)

DOI: https://doi.org/10.3847/0004-637X/824/2/121 · OSTI ID:1352121

De Rosa, Robert J.  ^[1]; Rameau, Julien ^[2]; Patience, Jenny ^[3]; Graham, James R. ^[1]; Doyon, René ^[2]; Lafrenière, David  ^[2]; Macintosh, Bruce  ^[4]; Pueyo, Laurent ^[5]; Rajan, Abhijith ^[3]; Wang, Jason J.  ^[1]; Ward-Duong, Kimberly ^[3]; Hung, Li -Wei ^[6]; Maire, Jérôme ^[7]; Nielsen, Eric L. ^[8]; Ammons, S. Mark  ^[9]; Bulger, Joanna ^[10]; Cardwell, Andrew ^[11]; Chilcote, Jeffrey K. ^[7]; Galvez, Ramon L. ^[12]; Gerard, Benjamin L.  ^[13] ; Goodsell, Stephen  ^[14]; Hartung, Markus ^[12]; Hibon, Pascale ^[15]; Ingraham, Patrick ^[16]; Johnson-Groh, Mara ^[13]; Kalas, Paul ^[17]; Konopacky, Quinn M.  ^[18]; Marchis, Franck  ^[19]; Marois, Christian  ^[20]; Metchev, Stanimir  ^[21]; Morzinski, Katie M.  ^[11]; Oppenheimer, Rebecca  ^[22]; Perrin, Marshall D.  ^[5]; Rantakyrö, Fredrik T.  ^[12]; Savransky, Dmitry  ^[23]; Thomas, Sandrine ^[13]

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1. Univ. of California, Berkeley, CA (United States)
2. Univ. de Montreal, Montreal, QC (Canada)
3. Arizona State Univ., Tempe, AZ (United States)
4. Stanford Univ., Stanford, CA (United States)
5. Space Telescope Science Institute, Baltimore, MD (United States)
6. Univ. of California, Los Angeles, CA (United States)
7. Univ. of Toronto, Toronto, ON (Canada)
8. Stanford Univ., Stanford, CA (United States); SETI Institute, Mountain View, CA (United States)
9. Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)
10. Subaru Telescope, Hilo, HI (United States)
11. Univ. of Arizona, Tucson, AZ (United States)
12. Gemini Observatory, La Serena (Chile)
13. Univ. of Victoria, Victoria, BC (Canada)
14. Durham Univ., Durham (United Kingdom); Gemini Observatory, Hilo, HI (United States)
15. European Southern Observatory, Santiago (Chile)
16. Large Synoptic Survey Telescope, Tucson, AZ (United States)
17. Univ. of California, Berkeley, CA (United States); SETI Institute, Mountain View, CA (United States)
18. Univ. of California San Diego, La Jolla, CA (United States)
19. SETI Institute, Mountain View, CA (United States)
20. Univ. of Victoria, Victoria, BC (Canada); National Research Council of Canada Herzberg, Victoria, BC (Canada)
21. The Univ. of Western Ontario, London, ON (Canada); Stony Brook Univ., Stony Brook, NY (United States)
22. American Museum of Natural History, New York, NY (United States)
23. Cornell Univ., Ithaca, NY (United States)

Here, we present new H (1.5–1.8 μm) photometric and K ₁ (1.9–2.2 μm) spectroscopic observations of the young exoplanet HD 95086 b obtained with the Gemini Planet Imager. The H-band magnitude has been significantly improved relative to previous measurements, whereas the low-resolution K ₁ ($$\lambda /\delta \lambda \approx 66$$) spectrum is featureless within the measurement uncertainties and presents a monotonically increasing pseudo-continuum consistent with a cloudy atmosphere. By combining these new measurements with literature $$L^{\prime} $$ photometry, we compare the spectral energy distribution (SED) of the planet to other young planetary-mass companions, field brown dwarfs, and to the predictions of grids of model atmospheres. HD 95086 b is over a magnitude redder in $${K}_{1}-L^{\prime} $$ color than 2MASS J12073346–3932539 b and HR 8799 c and d, despite having a similar $$L^{\prime} $$ magnitude. Considering only the near-infrared measurements, HD 95086 b is most analogous to the brown dwarfs 2MASS J2244316+204343 and 2MASS J21481633+4003594, both of which are thought to have dusty atmospheres. Morphologically, the SED of HD 95086 b is best fit by low temperature ($${T}_{{\rm{eff}}}$$ = 800–1300 K), low surface gravity spectra from models which simulate high photospheric dust content. This range of effective temperatures is consistent with field L/T transition objects, but the spectral type of HD 95086 b is poorly constrained between early L and late T due to its unusual position the color–magnitude diagram, demonstrating the difficulty in spectral typing young, low surface gravity substellar objects. As one of the reddest such objects, HD 95086 b represents an important empirical benchmark against which our current understanding of the atmospheric properties of young extrasolar planets can be tested.

• Research Organization: Lawrence Livermore National Laboratory (LLNL), Livermore, CA (United States)
• Sponsoring Organization: USDOE
• Grant/Contract Number: AC52-07NA27344; NNX15AD95G/NEXSS; NNX15AC89G; NNX14AJ80G
• OSTI ID: 1352121
• Report Number(s): LLNL-JRNL-717745
• Journal Information: The Astrophysical Journal (Online), Vol. 824, Issue 2; ISSN 1538-4357
• Publisher: Institute of Physics (IOP)Copyright Statement
• Country of Publication: United States
• Language: English