NEAR-INFRARED OBSERVATIONS OF GQ LUP b USING THE GEMINI INTEGRAL FIELD SPECTROGRAPH NIFS

We present new JHK spectroscopy (R ∼ 5000) of GQ Lup b, acquired with the Near-Infrared Integral Field Spectrograph and the adaptive optics system ALTAIR at the Gemini North telescope. Angular differential imaging was used in the J and H bands to suppress the speckle noise from GQ Lup A; we show that this approach can provide improvements in signal-to-noise ratio (S/N) by a factor of 2–6 for companions located at subarcsecond separations. Based on high-quality observations and Global Astrometric lnterferometer for Astrophysics synthetic spectra, we estimate the companion effective temperature to Teff = 2400 ± 100 K, its gravity to log g = 4.0 ± 0.5, and its luminosity to log(L/L☉) = −2.47 ± 0.28. Comparisons with the predictions of the DUSTY evolutionary tracks allow us to constrain the mass of GQ Lup b to 8–60 MJup, most likely in the brown dwarf regime. Compared with the spectra published by Seifahrt and collaborators, our spectra of GQ Lup b are significantly redder (by 15%–50%) and do not show important Paβ emission. Our spectra are in excellent agreement with the lower S/N spectra previously published by McElwain and collaborators.

[1]  B. Macintosh,et al.  Direct Imaging of Multiple Planets Orbiting the Star HR 8799 , 2008, Science.

[2]  Mark Clampin,et al.  Optical Images of an Exosolar Planet 25 Light-Years from Earth , 2008, Science.

[3]  Jena,et al.  Direct evidence of a sub-stellar companion around CT Chamaeleontis , 2008, 0809.2812.

[4]  David Lafreniere,et al.  Direct Imaging and Spectroscopy of a Planetary-Mass Candidate Companion to a Young Solar Analog , 2008, 0809.1424.

[5]  T. Barman,et al.  A Sample of Very Young Field L Dwarfs and Implications for the Brown Dwarf “Lithium Test” at Early Ages , 2008, 0808.3153.

[6]  R. Neuhaeuser,et al.  Astrometric and photometric monitoring of GQ Lupi and its sub-stellar companion , 2008, 0801.2287.

[7]  Markus Janson,et al.  Integral field spectroscopy of L 449-1 -- A test case for spectral differential imaging with SINFONI , 2008 .

[8]  R. F. Jameson,et al.  Near‐infrared cross‐dispersed spectroscopy of brown dwarf candidates in the Upper Sco association★ , 2007, 0711.1109.

[9]  M. Meyer,et al.  An Improbable Solution to the Underluminosity of 2M1207B: A Hot Protoplanet Collision Afterglow , 2007, 0709.0456.

[10]  C. Broeg,et al.  Rotational period of GQ Lupi , 2007 .

[11]  K. Stassun,et al.  A Surprising Reversal of Temperatures in the Brown Dwarf Eclipsing Binary 2MASS J05352184–0546085 , 2007, 0704.3106.

[12]  N. Thatte,et al.  Very high contrast integral field spectroscopy of AB Doradus C: 9-mag contrast at 0.2 arcsec without a coronagraph using spectral deconvolution , 2007, astro-ph/0703565.

[13]  Michael C. Liu,et al.  Characterizing Young Brown Dwarfs Using Low-Resolution Near-Infrared Spectra , 2006, astro-ph/0611408.

[14]  R. Neuhaeuser,et al.  Near-IR integral-field spectroscopy of the companion to GQ Lup , 2006, astro-ph/0612250.

[15]  M. McElwain,et al.  First High-Contrast Science with an Integral Field Spectrograph: The Substellar Companion to GQ Lupi , 2006, astro-ph/0610265.

[16]  B. Macintosh,et al.  GQ Lup B Visible and Near-Infrared Photometric Analysis , 2006, astro-ph/0610058.

[17]  L. Testi,et al.  Accretion in rho-Ophiuchi brown dwarfs: infrared hydrogen line ratios , 2006, astro-ph/0609291.

[18]  René Doyon,et al.  Improving the Speckle Noise Attenuation of Simultaneous Spectral Differential Imaging with a Focal Plane Holographic Diffuser , 2006, SPIE Astronomical Telescopes + Instrumentation.

[19]  Keivan G. Stassun,et al.  Discovery of two young brown dwarfs in an eclipsing binary system , 2006, Nature.

[20]  L. Testi,et al.  Accretion in the ρ-Ophiuchi pre-main sequence stars , 2006, astro-ph/0602618.

[21]  R. Jayawardhana,et al.  Variable Accretion and Outflow in Young Brown Dwarfs , 2005, astro-ph/0510629.

[22]  B. Macintosh,et al.  Angular Differential Imaging: A Powerful High-Contrast Imaging Technique , 2005, astro-ph/0512335.

[23]  T. Barman,et al.  Discovery of a Very Young Field L Dwarf, 2MASS J01415823–4633574 , 2005, astro-ph/0511462.

[24]  P. Hauschildt,et al.  Evidence for a co-moving sub-stellar companion of GQ Lup , 2005, astro-ph/0503691.

[25]  M. Perryman,et al.  The Three-Dimensional Universe with Gaia , 2005 .

[26]  John T. Rayner,et al.  An Infrared Spectroscopic Sequence of M, L, and T Dwarfs , 2004, astro-ph/0412313.

[27]  D. Mouillet,et al.  A giant planet candidate near a young brown dwarf - Direct VLT/NACO observations using IR wavefront sensing , 2004, astro-ph/0409323.

[28]  J. Brinkmann,et al.  L′ and M′ Photometry of Ultracool Dwarfs , 2004, astro-ph/0402475.

[29]  Adam J. Burgasser,et al.  The NIRSPEC Brown Dwarf Spectroscopic Survey. I. Low-Resolution Near-Infrared Spectra , 2003, astro-ph/0309257.

[30]  George H. Rieke,et al.  Gravity Indicators in the Near-Infrared Spectra of Brown Dwarfs , 2003, astro-ph/0305147.

[31]  F. Allard,et al.  Evolutionary models for cool brown dwarfs and extrasolar giant planets. The case of HD 209458 , 2003, astro-ph/0302293.

[32]  B. Krauskopf,et al.  Proc of SPIE , 2003 .

[33]  H. Ford,et al.  Imaging Spectroscopy for Extrasolar Planet Detection , 2002, astro-ph/0209078.

[34]  F. Allard,et al.  Evolutionary models for low-mass stars and brown dwarfs: uncertainties and limits at very young ages , 2001, astro-ph/0111385.

[35]  N. Batalha,et al.  Variability of Southern T Tauri Stars. I. The Continuum and the Hβ Inverse P Cygni Profile of GQ Lupi , 2000, astro-ph/0009134.

[36]  F. Allard,et al.  Evolutionary Models for Very Low-Mass Stars and Brown Dwarfs with Dusty Atmospheres , 2000, astro-ph/0005557.

[37]  Gurjeet Singh,et al.  Innovations in Gemini adaptive optics system design , 1998, Astronomical Telescopes and Instrumentation.

[38]  T. Guillot,et al.  A Nongray Theory of Extrasolar Giant Planets and Brown Dwarfs , 1997, astro-ph/9705201.