Query : 2018A&A...616A.146P

2018A&A...616A.146P - Astronomy and Astrophysics, volume 616A, 146-146 (2018/8-1)

Molecule mapping of HR8799b using OSIRIS on Keck. Strong detection of water and carbon monoxide, but no methane.


Abstract (from CDS):

Context. In 2015, Barman et al. (2015ApJ...804...61B) presented detections of absorption from water, carbon monoxide, and methane in the atmosphere of the directly imaged exoplanet HR8799b using integral field spectroscopy (IFS) with OSIRIS on the Keck II telescope. We recently devised a new method to analyse IFU data, called molecule mapping, searching for high-frequency signatures of particular molecules in an IFU data cube.
Aims. The aim of this paper is to use the molecule mapping technique to search for the previously detected spectral signatures in HR8799b using the same data, allowing a comparison of molecule mapping with previous methods.
Methods. The medium-resolution H- and K-band pipeline-reduced archival data were retrieved from the Keck archive facility. Telluric and stellar lines were removed from each spectrum in the data cube, after which the residuals were cross-correlated with model spectra of carbon monoxide, water, and methane.
Results. Both carbon monoxide and water are clearly detected at high signal-to-noise, however, methane is not retrieved.
Conclusions. Molecule mapping works very well on the OSIRIS data of exoplanet HR8799b. However, it is not evident why methane is detected in the original analysis, but not with the molecule mapping technique. Possible causes could be the presence of telluric residuals, different spectral filtering techniques, or the use of different methane models. We do note that in the original analysis methane was only detected in the K-band, while the H-band methane signal could be expected to be comparably strong. More sensitive observations with the JWST will be capable of confirming or disproving the presence of methane in this planet at high confidence.

Abstract Copyright: © ESO 2018

Journal keyword(s): planets and satellites: atmospheres - methods: data analysis - techniques: spectroscopic - infrared: planetary systems

Simbad objects: 3

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Number of rows : 3
N Identifier Otype ICRS (J2000)
ICRS (J2000)
Mag U Mag B Mag V Mag R Mag I Sp type #ref
1850 - 2021
1 * bet Pic PM* 05 47 17.0876901 -51 03 59.441135 4.13 4.03 3.86 3.74 3.58 A6V 1718 1
2 * bet Pic b Pl 05 47 17.0876901 -51 03 59.441135           ~ 392 1
3 HD 218396 El* 23 07 28.7156905667 +21 08 03.302133882   6.21 5.953     F0+VkA5mA5 964 0

    Equat.    Gal    SGal    Ecl

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