Abstract
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.
Original language | English (US) |
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Pages (from-to) | 1098-1106 |
Number of pages | 9 |
Journal | Astrophysical Journal |
Volume | 704 |
Issue number | 2 |
DOIs | |
State | Published - Oct 20 2009 |
Externally published | Yes |
Keywords
- High angular resolution - techniques
- Individual (GQ Lup) - stars
- Low-mass, brown dwarfs - stars
- Planetary systems - stars
- Pre-main sequence - techniques
- Spectroscopic
ASJC Scopus subject areas
- Astronomy and Astrophysics
- Space and Planetary Science