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Title: Characterizing 51 Eri b from 1 to 5 μm: A Partly Cloudy Exoplanet

Abstract

Here, we present spectrophotometry spanning 1–5 μm of 51 Eridani b, a 2–10 $${M}_{\mathrm{Jup}}$$ planet discovered by the Gemini Planet Imager Exoplanet Survey. In this study, we present new K1 (1.90–2.19 μm) and K2 (2.10–2.40 μm) spectra taken with the Gemini Planet Imager as well as an updated L P (3.76 μm) and new M S (4.67 μm) photometry from the NIRC2 Narrow camera. The new data were combined with J (1.13–1.35 μm) and H (1.50–1.80 μm) spectra from the discovery epoch with the goal of better characterizing the planet properties. The 51 Eri b photometry is redder than field brown dwarfs as well as known young T-dwarfs with similar spectral type (between T4 and T8), and we propose that 51 Eri b might be in the process of undergoing the transition from L-type to T-type. We used two complementary atmosphere model grids including either deep iron/silicate clouds or sulfide/salt clouds in the photosphere, spanning a range of cloud properties, including fully cloudy, cloud-free, and patchy/intermediate-opacity clouds. The model fits suggest that 51 Eri b has an effective temperature ranging between 605 and 737 K, a solar metallicity, and a surface gravity of log(g) = 3.5–4.0 dex, and the atmosphere requires a patchy cloud atmosphere to model the spectral energy distribution (SED). From the model atmospheres, we infer a luminosity for the planet of –5.83 to –5.93 ($$\mathrm{log}L/{L}_{\odot }$$), leaving 51 Eri b in the unique position of being one of the only directly imaged planets consistent with having formed via a cold-start scenario. Comparisons of the planet SED against warm-start models indicate that the planet luminosity is best reproduced by a planet formed via core accretion with a core mass between 15 and 127 $${M}_{\oplus }$$.

Authors:
ORCiD logo [1]; ORCiD logo [2]; ORCiD logo [3]; ORCiD logo [4];  [3]; ORCiD logo [5]; ORCiD logo [6]; ORCiD logo [7];  [1];  [8]; ORCiD logo [9]; ORCiD logo [1]; ORCiD logo [10]; ORCiD logo [11];  [5]; ORCiD logo [12]; ORCiD logo [13]; ORCiD logo [10]; ORCiD logo [14]; ORCiD logo [15] more »; ORCiD logo [5];  [2]; ORCiD logo [16]; ORCiD logo [3]; ORCiD logo [11]; ORCiD logo [5]; ORCiD logo [17]; ORCiD logo [18]; ORCiD logo [19]; ORCiD logo [20]; ORCiD logo [11]; ORCiD logo [21]; ORCiD logo [22];  [23]; ORCiD logo [24]; ORCiD logo [2]; ORCiD logo [11];  [24]; ORCiD logo [25]; ORCiD logo [26]; ORCiD logo [27]; ORCiD logo [12]; ORCiD logo [28]; ORCiD logo [29]; ORCiD logo [30]; ORCiD logo [27]; ORCiD logo [8];  [30]; ORCiD logo [20]; ORCiD logo [5]; ORCiD logo [31]; ORCiD logo [1]; ORCiD logo [8]; ORCiD logo [15]; ORCiD logo [8]; ORCiD logo [21];  [27]; ORCiD logo [27]; ORCiD logo [3];  [32]; ORCiD logo [33] « less
  1. Arizona State Univ., Tempe, AZ (United States)
  2. Univ. de Montreal, Montreal, QC (Canada)
  3. Univ. of California, Berkeley, CA (United States)
  4. NASA Ames Research Center, Mountain View, CA (United States)
  5. Stanford Univ., Stanford, CA (United States)
  6. National Research Council of Canada Herzberg, Victoria, BC (Canada); Univ. of Victoria, Victoria, BC (Canada)
  7. Harvard Univ., Cambridge, MA (United States)
  8. Space Telescope Science Institute, Baltimore, MD (United States)
  9. Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
  10. Princeton Univ., Princeton, NJ (United States)
  11. Univ. of California, Los Angeles, CA (United States)
  12. Univ. of Arizona, Tucson, AZ (United States)
  13. Subaru Telescope, Hilo, HI (United States)
  14. Univ. of Toronto, Toronto, ON (Canada)
  15. Univ. of Georgia, Athens, GA (United States)
  16. Univ. of California, Berkeley, CA (United States); Univ. Grenoble Alpes/CNRS, Grenoble (France)
  17. Univ. of California, Santa Cruz, CA (United States)
  18. Gemini Observatory, Hilo, HI (United States)
  19. Univ. of Michigan, Ann Arbor, MI (United States)
  20. Gemini Observatory, La Serena (Chile)
  21. Large Synoptic Survey Telescope, Tucson, AZ (United States)
  22. Univ. of Victoria, Victoria, BC (Canada)
  23. Univ. of California, Berkeley, CA (United States); SETI Institute, Mountain View, CA (United States)
  24. Univ. of California San Diego, La Jolla, CA (United States)
  25. SETI Institute, Mountain View, CA (United States)
  26. The Univ. of Western Ontario, London, ON (Canada); Stony Brook Univ., Stony Brook, NY (United States)
  27. California Inst. of Technology (CalTech), Pasadena, CA (United States)
  28. Stanford Univ., Stanford, CA (United States); SETI Institute, Mountain View, CA (United States)
  29. American Museum of Natural History, New York, NY (United States)
  30. Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)
  31. Cornell Univ., Ithaca, NY (United States)
  32. The Aerospace Corp., El Segundo, CA (United States)
  33. Johns Hopkins Univ., Baltimore, MD (United States)
Publication Date:
Research Org.:
Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
Sponsoring Org.:
National Aeronautic and Space Administration (NASA); USDOE
OSTI Identifier:
1375176
Report Number(s):
LA-UR-17-20913
Journal ID: ISSN 1538-3881
Grant/Contract Number:
AC52-06NA25396
Resource Type:
Journal Article: Accepted Manuscript
Journal Name:
Astronomical Journal (Online)
Additional Journal Information:
Journal Name: Astronomical Journal (Online); Journal Volume: 154; Journal Issue: 1; Journal ID: ISSN 1538-3881
Publisher:
IOP Publishing - AAAS
Country of Publication:
United States
Language:
English
Subject:
79 ASTRONOMY AND ASTROPHYSICS; instrumentation: adaptive optics; planets and satellites: atmospheres; planets and satellites: composition; planets and satellites: gaseous planets; stars: individual (51 Eridani)

Citation Formats

Rajan, Abhijith, Rameau, Julien, Rosa, Robert J. De, Marley, Mark S., Graham, James R., Macintosh, Bruce, Marois, Christian, Morley, Caroline, Patience, Jennifer, Pueyo, Laurent, Saumon, Didier, Ward-Duong, Kimberly, Ammons, S. Mark, Arriaga, Pauline, Bailey, Vanessa P., Barman, Travis, Bulger, Joanna, Burrows, Adam S., Chilcote, Jeffrey, Cotten, Tara, Czekala, Ian, Doyon, Rene, Duchene, Gaspard, Esposito, Thomas M., Fitzgerald, Michael P., Follette, Katherine B., Fortney, Jonathan J., Goodsell, Stephen J., Greenbaum, Alexandra Z., Hibon, Pascale, Hung, Li -Wei, Ingraham, Patrick, Johnson-Groh, Mara, Kalas, Paul, Konopacky, Quinn, Lafreniere, David, Larkin, James E., Maire, Jerome, Marchis, Franck, Metchev, Stanimir, Millar-Blanchaer, Maxwell A., Morzinski, Katie M., Nielsen, Eric L., Oppenheimer, Rebecca, Palmer, David, Patel, Rahul I., Perrin, Marshall, Poyneer, Lisa, Rantakyro, Fredrik T., Ruffio, Jean -Baptiste, Savransky, Dmitry, Schneider, Adam C., Sivaramakrishnan, Anand, Song, Inseok, Soummer, Remi, Thomas, Sandrine, Vasisht, Gautam, Wallace, J. Kent, Wang, Jason J., Wiktorowicz, Sloane, and Wolff, Schuyler. Characterizing 51 Eri b from 1 to 5 μm: A Partly Cloudy Exoplanet. United States: N. p., 2017. Web. doi:10.3847/1538-3881/aa74db.
Rajan, Abhijith, Rameau, Julien, Rosa, Robert J. De, Marley, Mark S., Graham, James R., Macintosh, Bruce, Marois, Christian, Morley, Caroline, Patience, Jennifer, Pueyo, Laurent, Saumon, Didier, Ward-Duong, Kimberly, Ammons, S. Mark, Arriaga, Pauline, Bailey, Vanessa P., Barman, Travis, Bulger, Joanna, Burrows, Adam S., Chilcote, Jeffrey, Cotten, Tara, Czekala, Ian, Doyon, Rene, Duchene, Gaspard, Esposito, Thomas M., Fitzgerald, Michael P., Follette, Katherine B., Fortney, Jonathan J., Goodsell, Stephen J., Greenbaum, Alexandra Z., Hibon, Pascale, Hung, Li -Wei, Ingraham, Patrick, Johnson-Groh, Mara, Kalas, Paul, Konopacky, Quinn, Lafreniere, David, Larkin, James E., Maire, Jerome, Marchis, Franck, Metchev, Stanimir, Millar-Blanchaer, Maxwell A., Morzinski, Katie M., Nielsen, Eric L., Oppenheimer, Rebecca, Palmer, David, Patel, Rahul I., Perrin, Marshall, Poyneer, Lisa, Rantakyro, Fredrik T., Ruffio, Jean -Baptiste, Savransky, Dmitry, Schneider, Adam C., Sivaramakrishnan, Anand, Song, Inseok, Soummer, Remi, Thomas, Sandrine, Vasisht, Gautam, Wallace, J. Kent, Wang, Jason J., Wiktorowicz, Sloane, & Wolff, Schuyler. Characterizing 51 Eri b from 1 to 5 μm: A Partly Cloudy Exoplanet. United States. doi:10.3847/1538-3881/aa74db.
Rajan, Abhijith, Rameau, Julien, Rosa, Robert J. De, Marley, Mark S., Graham, James R., Macintosh, Bruce, Marois, Christian, Morley, Caroline, Patience, Jennifer, Pueyo, Laurent, Saumon, Didier, Ward-Duong, Kimberly, Ammons, S. Mark, Arriaga, Pauline, Bailey, Vanessa P., Barman, Travis, Bulger, Joanna, Burrows, Adam S., Chilcote, Jeffrey, Cotten, Tara, Czekala, Ian, Doyon, Rene, Duchene, Gaspard, Esposito, Thomas M., Fitzgerald, Michael P., Follette, Katherine B., Fortney, Jonathan J., Goodsell, Stephen J., Greenbaum, Alexandra Z., Hibon, Pascale, Hung, Li -Wei, Ingraham, Patrick, Johnson-Groh, Mara, Kalas, Paul, Konopacky, Quinn, Lafreniere, David, Larkin, James E., Maire, Jerome, Marchis, Franck, Metchev, Stanimir, Millar-Blanchaer, Maxwell A., Morzinski, Katie M., Nielsen, Eric L., Oppenheimer, Rebecca, Palmer, David, Patel, Rahul I., Perrin, Marshall, Poyneer, Lisa, Rantakyro, Fredrik T., Ruffio, Jean -Baptiste, Savransky, Dmitry, Schneider, Adam C., Sivaramakrishnan, Anand, Song, Inseok, Soummer, Remi, Thomas, Sandrine, Vasisht, Gautam, Wallace, J. Kent, Wang, Jason J., Wiktorowicz, Sloane, and Wolff, Schuyler. 2017. "Characterizing 51 Eri b from 1 to 5 μm: A Partly Cloudy Exoplanet". United States. doi:10.3847/1538-3881/aa74db.
@article{osti_1375176,
title = {Characterizing 51 Eri b from 1 to 5 μm: A Partly Cloudy Exoplanet},
author = {Rajan, Abhijith and Rameau, Julien and Rosa, Robert J. De and Marley, Mark S. and Graham, James R. and Macintosh, Bruce and Marois, Christian and Morley, Caroline and Patience, Jennifer and Pueyo, Laurent and Saumon, Didier and Ward-Duong, Kimberly and Ammons, S. Mark and Arriaga, Pauline and Bailey, Vanessa P. and Barman, Travis and Bulger, Joanna and Burrows, Adam S. and Chilcote, Jeffrey and Cotten, Tara and Czekala, Ian and Doyon, Rene and Duchene, Gaspard and Esposito, Thomas M. and Fitzgerald, Michael P. and Follette, Katherine B. and Fortney, Jonathan J. and Goodsell, Stephen J. and Greenbaum, Alexandra Z. and Hibon, Pascale and Hung, Li -Wei and Ingraham, Patrick and Johnson-Groh, Mara and Kalas, Paul and Konopacky, Quinn and Lafreniere, David and Larkin, James E. and Maire, Jerome and Marchis, Franck and Metchev, Stanimir and Millar-Blanchaer, Maxwell A. and Morzinski, Katie M. and Nielsen, Eric L. and Oppenheimer, Rebecca and Palmer, David and Patel, Rahul I. and Perrin, Marshall and Poyneer, Lisa and Rantakyro, Fredrik T. and Ruffio, Jean -Baptiste and Savransky, Dmitry and Schneider, Adam C. and Sivaramakrishnan, Anand and Song, Inseok and Soummer, Remi and Thomas, Sandrine and Vasisht, Gautam and Wallace, J. Kent and Wang, Jason J. and Wiktorowicz, Sloane and Wolff, Schuyler},
abstractNote = {Here, we present spectrophotometry spanning 1–5 μm of 51 Eridani b, a 2–10 ${M}_{\mathrm{Jup}}$ planet discovered by the Gemini Planet Imager Exoplanet Survey. In this study, we present new K1 (1.90–2.19 μm) and K2 (2.10–2.40 μm) spectra taken with the Gemini Planet Imager as well as an updated L P (3.76 μm) and new M S (4.67 μm) photometry from the NIRC2 Narrow camera. The new data were combined with J (1.13–1.35 μm) and H (1.50–1.80 μm) spectra from the discovery epoch with the goal of better characterizing the planet properties. The 51 Eri b photometry is redder than field brown dwarfs as well as known young T-dwarfs with similar spectral type (between T4 and T8), and we propose that 51 Eri b might be in the process of undergoing the transition from L-type to T-type. We used two complementary atmosphere model grids including either deep iron/silicate clouds or sulfide/salt clouds in the photosphere, spanning a range of cloud properties, including fully cloudy, cloud-free, and patchy/intermediate-opacity clouds. The model fits suggest that 51 Eri b has an effective temperature ranging between 605 and 737 K, a solar metallicity, and a surface gravity of log(g) = 3.5–4.0 dex, and the atmosphere requires a patchy cloud atmosphere to model the spectral energy distribution (SED). From the model atmospheres, we infer a luminosity for the planet of –5.83 to –5.93 ($\mathrm{log}L/{L}_{\odot }$), leaving 51 Eri b in the unique position of being one of the only directly imaged planets consistent with having formed via a cold-start scenario. Comparisons of the planet SED against warm-start models indicate that the planet luminosity is best reproduced by a planet formed via core accretion with a core mass between 15 and 127 ${M}_{\oplus }$.},
doi = {10.3847/1538-3881/aa74db},
journal = {Astronomical Journal (Online)},
number = 1,
volume = 154,
place = {United States},
year = 2017,
month = 6
}

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