2018A&A...620A..97S


C.D.S. - SIMBAD4 rel 1.7 - 2021.01.26CET00:34:40

2018A&A...620A..97S - Astronomy and Astrophysics, volume 620A, 97-97 (2018/12-1)

Detection of He I λ10830 Å absorption on HD 189733 b with CARMENES high-resolution transmission spectroscopy.

SALZ M., CZESLA S., SCHNEIDER P.C., NAGEL E., SCHMITT J.H.M.M., NORTMANN L., ALONSO-FLORIANO F.J., LOPEZ-PUERTAS M., LAMPON M., BAUER F.F., SNELLEN I.A.G., PALLE E., CABALLERO J.A., YAN F., CHEN G., SANZ-FORCADA J., AMADO P.J., QUIRRENBACH A., RIBAS I., REINERS A., BEJAR V.J.S., CASASAYAS-BARRIS N., CORTES-CONTRERAS M., DREIZLER S., GUENTHER E.W., HENNING T., JEFFERS S.V., KAMINSKI A., KURSTER M., LAFARGA M., LARA L.M., MOLAVERDIKHANI K., MONTES D., MORALES J.C., SANCHEZ-LOPEZ A., SEIFERT W., ZAPATERO OSORIO M.R. and ZECHMEISTER M.

Abstract (from CDS):

We present three transit observations of HD 189733 b obtained with the high-resolution spectrograph CARMENES at Calar Alto. A strong absorption signal is detected in the near-infrared HeI triplet at 10830Å in all three transits. During mid-transit, the mean absorption level is 0.88±0.04% measured in a ±10km/s range at a net blueshift of -3.5±0.4km/s (10829.84-10830.57Å). The absorption signal exhibits radial velocities of +6.5±3.1km/s and -12.6±1.0km/s during ingress and egress, respectively; all radial velocities are measured in the planetary rest frame. We show that stellar activity related pseudo-signals interfere with the planetary atmospheric absorption signal. They could contribute as much as 80% of the observed signal and might also affect the observed radial velocity signature, but pseudo-signals are very unlikely to explain the entire signal. The observed line ratio between the two unresolved and the third line of the HeI triplet is 2.8±0.2, which strongly deviates from the value expected for an optically thin atmospheres. When interpreted in terms of absorption in the planetary atmosphere, this favors a compact helium atmosphere with an extent of only 0.2 planetary radii and a substantial column density on the order of 4x1012cm–2. The observed radial velocities can be understood either in terms of atmospheric circulation with equatorial superrotation or as a sign of an asymmetric atmospheric component of evaporating material. We detect no clear signature of ongoing evaporation, like pre- or post-transit absorption, which could indicate material beyond the planetary Roche lobe, or radial velocities in excess of the escape velocity. These findings do not contradict planetary evaporation, but only show that the detected helium absorption in HD 189733 b does not trace the atmospheric layers that show pronounced escape signatures.

Abstract Copyright: © ESO 2018

Journal keyword(s): planets and satellites: atmospheres - planets and satellites: individual: HD 189773 b - planet-star interactions - techniques: spectroscopic - infrared: planetary systems - stars: activity

Simbad objects: 10

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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 - 2021
#notes
1 WASP-12b Pl 06 30 32.7966788910 +29 40 20.266334158           G0 582 1
2 Ross 905b Pl 11 42 11.0933874353 +26 42 23.658083337           ~ 627 1
3 K2-235b Pl 12 33 32.8440958980 -10 08 46.223886777           ~ 62 0
4 [MMN2007] A1 gLS 14 17 35.9 +52 26 46     21.53   19.69 ~ 77 0
5 HD 189733b Pl 20 00 43.7130382888 +22 42 39.071811263           ~ 1141 1
6 HD 189733 BY* 20 00 43.7130382888 +22 42 39.071811263 9.241 8.578 7.648 7.126 6.68 K2V 744 1
7 HD 195689b Pl 20 31 26.3534038246 +39 56 19.765154336           ~ 116 0
8 BD-05 5432b Pl 21 00 06.1969250596 -05 05 40.037007561           ~ 58 1
9 HD 209458b Pl 22 03 10.7729598762 +18 53 03.548248479           ~ 1537 1
10 HD 209458 V* 22 03 10.7729598762 +18 53 03.548248479   8.21 7.63     F9V 1005 1

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