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Title: Spectroscopic characterization of HD 95086 b with the Gemini Planet Imager

Abstract

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.

Authors:
ORCiD logo [1];  [2];  [3];  [1];  [2]; ORCiD logo [2]; ORCiD logo [4];  [5];  [3]; ORCiD logo [1];  [3];  [6];  [7];  [8]; ORCiD logo [9];  [10];  [11];  [7];  [12]; ORCiD logo [13] more »; ORCiD logo [14];  [12];  [15];  [16];  [13];  [17]; ORCiD logo [18]; ORCiD logo [19]; ORCiD logo [20]; ORCiD logo [21]; ORCiD logo [11]; ORCiD logo [22]; ORCiD logo [5]; ORCiD logo [12]; ORCiD logo [23];  [13] « less
  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)
Publication Date:
Research Org.:
Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)
Sponsoring Org.:
USDOE
OSTI Identifier:
1352121
Report Number(s):
LLNL-JRNL-717745
Journal ID: ISSN 1538-4357
Grant/Contract Number:
AC52-07NA27344; NNX15AD95G/NEXSS; NNX15AC89G; NNX14AJ80G
Resource Type:
Journal Article: Accepted Manuscript
Journal Name:
The Astrophysical Journal (Online)
Additional Journal Information:
Journal Name: The Astrophysical Journal (Online); Journal Volume: 824; Journal Issue: 2; Journal ID: ISSN 1538-4357
Publisher:
Institute of Physics (IOP)
Country of Publication:
United States
Language:
English
Subject:
79 ASTRONOMY AND ASTROPHYSICS; infrared: planetary systems; instrumentation: adaptive optics; planets and satellites: atmospheres; stars: individual (HD 95086)

Citation Formats

De Rosa, Robert J., Rameau, Julien, Patience, Jenny, Graham, James R., Doyon, René, Lafrenière, David, Macintosh, Bruce, Pueyo, Laurent, Rajan, Abhijith, Wang, Jason J., Ward-Duong, Kimberly, Hung, Li -Wei, Maire, Jérôme, Nielsen, Eric L., Ammons, S. Mark, Bulger, Joanna, Cardwell, Andrew, Chilcote, Jeffrey K., Galvez, Ramon L., Gerard, Benjamin L., Goodsell, Stephen, Hartung, Markus, Hibon, Pascale, Ingraham, Patrick, Johnson-Groh, Mara, Kalas, Paul, Konopacky, Quinn M., Marchis, Franck, Marois, Christian, Metchev, Stanimir, Morzinski, Katie M., Oppenheimer, Rebecca, Perrin, Marshall D., Rantakyrö, Fredrik T., Savransky, Dmitry, and Thomas, Sandrine. Spectroscopic characterization of HD 95086 b with the Gemini Planet Imager. United States: N. p., 2016. Web. doi:10.3847/0004-637X/824/2/121.
De Rosa, Robert J., Rameau, Julien, Patience, Jenny, Graham, James R., Doyon, René, Lafrenière, David, Macintosh, Bruce, Pueyo, Laurent, Rajan, Abhijith, Wang, Jason J., Ward-Duong, Kimberly, Hung, Li -Wei, Maire, Jérôme, Nielsen, Eric L., Ammons, S. Mark, Bulger, Joanna, Cardwell, Andrew, Chilcote, Jeffrey K., Galvez, Ramon L., Gerard, Benjamin L., Goodsell, Stephen, Hartung, Markus, Hibon, Pascale, Ingraham, Patrick, Johnson-Groh, Mara, Kalas, Paul, Konopacky, Quinn M., Marchis, Franck, Marois, Christian, Metchev, Stanimir, Morzinski, Katie M., Oppenheimer, Rebecca, Perrin, Marshall D., Rantakyrö, Fredrik T., Savransky, Dmitry, & Thomas, Sandrine. Spectroscopic characterization of HD 95086 b with the Gemini Planet Imager. United States. doi:10.3847/0004-637X/824/2/121.
De Rosa, Robert J., Rameau, Julien, Patience, Jenny, Graham, James R., Doyon, René, Lafrenière, David, Macintosh, Bruce, Pueyo, Laurent, Rajan, Abhijith, Wang, Jason J., Ward-Duong, Kimberly, Hung, Li -Wei, Maire, Jérôme, Nielsen, Eric L., Ammons, S. Mark, Bulger, Joanna, Cardwell, Andrew, Chilcote, Jeffrey K., Galvez, Ramon L., Gerard, Benjamin L., Goodsell, Stephen, Hartung, Markus, Hibon, Pascale, Ingraham, Patrick, Johnson-Groh, Mara, Kalas, Paul, Konopacky, Quinn M., Marchis, Franck, Marois, Christian, Metchev, Stanimir, Morzinski, Katie M., Oppenheimer, Rebecca, Perrin, Marshall D., Rantakyrö, Fredrik T., Savransky, Dmitry, and Thomas, Sandrine. 2016. "Spectroscopic characterization of HD 95086 b with the Gemini Planet Imager". United States. doi:10.3847/0004-637X/824/2/121. https://www.osti.gov/servlets/purl/1352121.
@article{osti_1352121,
title = {Spectroscopic characterization of HD 95086 b with the Gemini Planet Imager},
author = {De Rosa, Robert J. and Rameau, Julien and Patience, Jenny and Graham, James R. and Doyon, René and Lafrenière, David and Macintosh, Bruce and Pueyo, Laurent and Rajan, Abhijith and Wang, Jason J. and Ward-Duong, Kimberly and Hung, Li -Wei and Maire, Jérôme and Nielsen, Eric L. and Ammons, S. Mark and Bulger, Joanna and Cardwell, Andrew and Chilcote, Jeffrey K. and Galvez, Ramon L. and Gerard, Benjamin L. and Goodsell, Stephen and Hartung, Markus and Hibon, Pascale and Ingraham, Patrick and Johnson-Groh, Mara and Kalas, Paul and Konopacky, Quinn M. and Marchis, Franck and Marois, Christian and Metchev, Stanimir and Morzinski, Katie M. and Oppenheimer, Rebecca and Perrin, Marshall D. and Rantakyrö, Fredrik T. and Savransky, Dmitry and Thomas, Sandrine},
abstractNote = {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.},
doi = {10.3847/0004-637X/824/2/121},
journal = {The Astrophysical Journal (Online)},
number = 2,
volume = 824,
place = {United States},
year = 2016,
month = 6
}

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  • Here, we present astrometric monitoring of the young exoplanet HD 95086 b obtained with the Gemini Planet Imager between 2013 and 2016. A small but significant position angle change is detected at constant separation; the orbital motion is confirmed with literature measurements. Efficient Monte Carlo techniques place preliminary constraints on the orbital parameters of HD 95086 b. With 68% confidence, a semimajor axis ofmore » $${61.7}_{-8.4}^{+20.7}$$ au and an inclination of $$153° {0}_{-13.5}^{+9.7}$$ are favored, with eccentricity less than 0.21. Under the assumption of a coplanar planet–disk system, the periastron of HD 95086 b is beyond 51 au with 68% confidence. Therefore, HD 95086 b cannot carve the entire gap inferred from the measured infrared excess in the SED of HD 95086. We use our sensitivity to additional planets to discuss specific scenarios presented in the literature to explain the geometry of the debris belts. We suggest that either two planets on moderately eccentric orbits or three to four planets with inhomogeneous masses and orbital properties are possible. As a result, the sensitivity to additional planetary companions within the observations presented in this study can be used to help further constrain future dynamical simulations of the planet–disk system.« less
  • Here, we present new spatially resolved astrometry and photometry from the Gemini Planet Imager of the inner binary of the young multiple star system V343 Normae, which is a member of the β Pictoris (β Pic) moving group. V343 Normae comprises a K0 and mid-M star in a ~4.5 year orbit (AaAb) and a wide 10'' M5 companion (B). By combining these data with archival astrometry and radial velocities we fit the orbit and measure individual masses for both components ofmore » $${M}_{\mathrm{Aa}}=1.10\pm 0.10\,{M}_{\odot }$$ and $${M}_{\mathrm{Ab}}=0.290\pm 0.018\,{M}_{\odot }$$. Comparing to theoretical isochrones, we find good agreement for the measured masses and JHK band magnitudes of the two components consistent with the age of the β Pic moving group. We derive a model-dependent age for the β Pic moving group of 26 ± 3 Myr by combining our results for V343 Normae with literature measurements for GJ 3305, which is another group member with resolved binary components and dynamical masses.« less
  • Detecting polarized light from self-luminous exoplanets has the potential to provide key information about rotation, surface gravity, cloud grain size, and cloud coverage. While field brown dwarfs with detected polarized emission are common, no exoplanet or substellar companion has yet been detected in polarized light. With the advent of high contrast imaging spectro-polarimeters such as GPI and SPHERE, such a detection may now be possible with careful treatment of instrumental polarization. In this paper, we present 28 minutes of H-band GPI polarimetric observations of the benchmark T5.5 companion HD 19467 B. We detect no polarization signal from the target, and place an upper limit on the degree of linear polarization ofmore » $${p}_{\mathrm{CL}99.73\%}\leqslant 2.4\%$$. In conclusion, we discuss our results in the context of T dwarf cloud models and photometric variability.« less
  • Using the recently installed Gemini Planet Imager (GPI), we have obtained the first H-band spectrum of the planetary companion to the nearby young star β Pictoris. GPI is designed to image and provide low-resolution spectra of Jupiter-sized, self-luminous planetary companions around young nearby stars. These observations were taken covering the H band (1.65 μm). The spectrum has a resolving power of ~45 and demonstrates the distinctive triangular shape of a cool substellar object with low surface gravity. Using atmospheric models, we find an effective temperature of 1600-1700 K and a surface gravity of log (g) = 3.5-4.5 (cgs units). Thesemore » values agree well with "hot-start" predictions from planetary evolution models for a gas giant with mass between 10 and 12 M Jup and age between 10 and 20 Myr.« less
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