2019A&A...623A..58A


Query : 2019A&A...623A..58A

2019A&A...623A..58A - Astronomy and Astrophysics, volume 623A, 58-58 (2019/3-1)

High-resolution confirmation of an extended helium atmosphere around WASP-107b.

ALLART R., BOURRIER V., LOVIS C., EHRENREICH D., ACEITUNO J., GUIJARRO A., PEPE F., SING D.K., SPAKE J.J. and WYTTENBACH A.

Abstract (from CDS):


Context. Probing the evaporation of exoplanet atmospheres is key to understanding the formation and evolution of exoplanetary systems. The main tracer of evaporation in the UV is the Lyman-α transition, which can reveal extended exospheres of neutral hydrogen. Recently, the near-infrared (NIR) metastable helium triplet (10833Å) revealed extended thermospheres in several exoplanets. This opens a new window into evaporation.
Aims. We aim at spectrally resolving the first helium absorption signature detected in the warm Saturn WASP-107b with the Wide Filed Camera 3 on board the Hubble Space Telescope (HST/WFC3).
Methods. We obtained one transit of WASP-107b with CARMENES installed on the 3.5m telescope at the Calar Alto observatory.
Results. We detect an excess helium absorption signature of 5.54±0.27% (20σ) in the planet rest frame during the transit. The detection is in agreement with the previous detection achieved with HST/WFC3. The signature shows an excess absorption in the blue part of the lines, suggesting that HeI atoms are escaping from the atmosphere of WASP-107b. We interpret the time-series absorption spectra using the 3D EVE code. Our observations can be explained by combining an extended thermosphere that fills half of the Roche lobe and a large exospheric tail sustained by an escape rate of metastable helium of about 106g/s. In this scenario, however, the upper atmosphere needs to be subjected to a reduced photoionisation and radiation pressure from the star for the model to match the observations.
Conclusions. We confirm the presence of helium in the atmosphere of WASP-107b at high confidence. The helium feature is detected from space and from the ground. The ground-based high-resolution signal brings detailed information about the spatial and dynamical structure of the upper atmosphere, and simulations suggest that the HeI signature of WASP-107b probes both its thermosphere and exosphere, establishing this signature as a robust probe of exoplanetary upper atmospheres. Surveys with NIR high-resolution spectrographs (e.g. CARMENES, the Spectrometre infrarouge (SPIRou), or the Near-Infrared Planet Searcher (NIRPS)) will deliver a statistical understanding of exoplanet thermospheres and exospheres through the helium triplet.

Abstract Copyright: © ESO 2019

Journal keyword(s): planets and satellites: atmospheres - planets and satellites: individual: WASP-107b - methods: observational - techniques: spectroscopic

Simbad objects: 10

goto Full paper

goto View the references in ADS

Number of rows : 10
N Identifier Otype ICRS (J2000)
RA
ICRS (J2000)
DEC
Mag U Mag B Mag V Mag R Mag I Sp type #ref
1850 - 2024
#notes
1 NAME LP 424-4b Pl 07 59 05.8395356736 +15 23 29.236065000           ~ 306 1
2 HD 85512 PM* 09 51 07.0518026760 -43 30 10.023686079 9.963 8.83 7.651 6.934 6.319 K6Vk: 220 1
3 Ross 905b Pl 11 42 11.0933350978 +26 42 23.650782778           ~ 815 1
4 WASP-107 PM* 12 33 32.8441110816 -10 08 46.225572324   14.62 11.47     K7V 67 0
5 K2-235b Pl 12 33 32.8441110816 -10 08 46.225572324           ~ 176 0
6 BD+47 2936 EB* 19 50 50.2472976936 +48 04 51.101390496       8.8   K4V 304 1
7 BD+47 2936b Pl 19 50 50.2472976936 +48 04 51.101390496           ~ 422 1
8 HD 189733b Pl 20 00 43.7129433648 +22 42 39.073143456           ~ 1448 1
9 BD-05 5432b Pl 21 00 06.1968214728 -05 05 40.034944176           ~ 150 1
10 HD 209458b Pl 22 03 10.7727465312 +18 53 03.549393384           ~ 1872 1

To bookmark this query, right click on this link: simbad:objects in 2019A&A...623A..58A and select 'bookmark this link' or equivalent in the popup menu