J/A+A/605/L9 NIR spectrum of exoplanet HIP 65426b (Chauvin+, 2017)
Discovery of a warm, dusty giant planet around HIP 65426.
Chauvin G., Desidera S., Lagrange A.-M., Vigan A., Gratton R., Langlois M.,
Bonnefoy M., Beuzit J.-L., Feldt M., Mouillet D., Meyer M., Cheetham A.,
Biller B., Boccaletti A., D'orazi V., Galicher R., Hagelberg J.,
Maire A.-L., Mesa D., Olofsson J., Samland M., Schmidt T.O.B., Sissa E.,
Bonavita M., Charnay B., Cudel M., Daemgen S., Delorme P.,
Janin-Potiron P., Janson M., Keppler M., Le Coroller H., Ligi R.,
Marleau G.D., Messina S., Molliere P., Mordasini C., Muller A., Peretti S.,
Perrot C., Rodet L., Rouan D., Zurlo A., Dominik C., Henning T., Menard F.,
Schmid H.-M., Turatto M., Udry S., Vakili F., Abe L., Antichi J.,
Baruffolo A., Baudoz P., Baudrand J., Blanchard P., Bazzon A., Buey T.,
Carbillet M., Carle M., Charton J., Cascone E., Claudi R., Costille A.,
Deboulbe A., De Caprio V., Dohlen K., Fantinel D., Feautrier P., Fusco T.,
Gigan P., Giro E., Gisler D., Gluck L., Hubin N., Hugot E., Jaquet M.,
Kasper M., Madec F., Magnard Y., Martinez P., Maurel D., Le Mignant D.,
Moller-Nilsson O., Llored M., Moulin T., Origne A., Pavlov A., Perret D.,
Petit C., Pragt J., Puget P., Rabou P., Ramos J., Rigal R., Rochat S.,
Roelfsema R., Rousset G., Roux A., Salasnich B., Sauvage J.-F., Sevin A.,
Soenke C., Stadler E., Suarez M., Weber L., Wildi F., Antoniucci S.,
Augereau J.-C., Baudino J.-L., Brandner W., Engler N., Girard J., Gry C.,
Kral Q., Kopytova T., Lagadec E., Milli J., Moutou C., Schlieder J.,
Szulagyi J., Thalmann C., Wahhaj Z.
<Astron. Astrophys., 605, L9 (2017)>
=2017A&A...605L...9C 2017A&A...605L...9C (SIMBAD/NED BibCode)
ADC_Keywords: Stars, double and multiple ; Planets ; Spectra, infrared
Keywords: instrumentation: adaptive optics -
instrumentation: high angular resolution - methods: observational -
planets and satellites: atmospheres -
planets and satellites: formation
Abstract:
The SHINE program is a high-contrast near-infrared survey of 600
young, nearby stars aimed at searching for and characterizing new
planetary systems using VLT/SPHERE's unprecedented high-contrast and
high-angular-resolution imaging capabilities. It is also intended to
place statistical constraints on the rate, mass and orbital
distributions of the giant planet population at large orbits as a
function of the stellar host mass and age to test planet-formation
theories.
We used the IRDIS dual-band imager and the IFS integral field
spectrograph of SPHERE to acquire high-contrast coronagraphic
differential near-infrared images and spectra of the young A2 star HIP
65426. It is a member of the ∼17Myr old Lower Centaurus-Crux
association.
At a separation of 830 mas (92au projected) from the star, we detect a
faint red companion. Multi-epoch observations confirm that it shares
common proper motion with HIP 65426. Spectro-photometric measurements
extracted with IFS and IRDIS between 0.95 and 2.2µm indicate a
warm, dusty atmosphere characteristic of young low-surface-gravity
L5-L7 dwarfs. Hot-start evolutionary models predict a luminosity
consistent with a 6-12MJup, Teff=1300-1600K and R=1.5±0.1RJup
giant planet. Finally, the comparison with Exo-REM and PHOENIX
BT-Settl synthetic atmosphere models gives consistent effective
temperatures but with slightly higher surface gravity solutions of
log(g)=4.0-5.0 with smaller radii (1.0-1.3RJup).
Given its physical and spectral properties, HIP 65426 b occupies a
rather unique placement in terms of age, mass, and spectral-type among
the currently known imaged planets. It represents a particularly
interesting case to study the presence of clouds as a function of
particle size, composition, and location in the atmosphere, to search
for signatures of non-equilibrium chemistry, and finally to test the
theory of planet formation and evolution.
Description:
HIP 65426 was observed on May 30th, 2016 under unstable conditions
(strong wind) with SPHERE. The observations were then repeated on June
26th, 2016.
Objects:
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RA (2000) DE Designation(s)
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13 24 36.10 -51 30 16.0 HIP 65426 = HD 116434
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File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
hip65426.dat 26 38 HIP65426b, VLT/SPHERE-IRDIFS spectrum
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Byte-by-byte Description of file: hip65426.dat
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Bytes Format Units Label Explanations
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1- 7 F7.5 um lambda Wavelength
9- 16 F8.6 --- NFlux Normalized flux
18- 26 F9.7 --- e_NFlux rms uncertainty on NFlux
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Acknowledgements:
Gael Chauvin, gael.chauvin(at)univ-grenoble-alpes.fr
(End) Patricia Vannier [CDS] 25-Oct-2017