2022A&A...659L...4B

Query : 2022A&A...659L...4B

2022A&A...659L...4B - Astronomy and Astrophysics, volume 659, L4-4 (2022/3-1)

CHEOPS geometric albedo of the hot Jupiter HD 209458 b.

BRANDEKER A., HENG K., LENDL M., PATEL J.A., MORRIS B.M., BROEG C., GUTERMAN P., BECK M., MAXTED P.F.L., DEMANGEON O., DELREZ L., DEMORY B.-O., KITZMANN D., SANTOS N.C., SINGH V., ALIBERT Y., ALONSO R., ANGLADA G., BARCZY T., BARRADO Y NAVASCUES D., BARROS S.C.C., BAUMJOHANN W., BECK T., BENZ W., BILLOT N., BONFILS X., BRUNO G., CABRERA J., CHARNOZ S., COLLIER CAMERON A., CORRAL VAN DAMME C., CSIZMADIA S., DAVIES M.B., DELEUIL M., DELINE A., EHRENREICH D., ERIKSON A., FARINATO J., FORTIER A., FOSSATI L., FRIDLUND M., GANDOLFI D., GILLON M., GUDEL M., HOYER S., ISAAK K.G., KISS L., LASKAR J., LECAVELIER DES ETANGS A., LOVIS C., LUNTZER A., MAGRIN D., NASCIMBENI V., OLOFSSON G., OTTENSAMER R., PAGANO I., PALLE E., PETER G., PIOTTO G., POLLACCO D., QUELOZ D., RAGAZZONI R., RANDO N., RAUER H., RIBAS I., SCANDARIATO G., SEGRANSAN D., SIMON A.E., SMITH A.M.S., SOUSA S.G., STELLER M., SZABO G.M., THOMAS N., UDRY S., VAN GROOTEL V., WALTON N. and WOLTER D.

Abstract (from CDS):

We report the detection of the secondary eclipse of the hot Jupiter HD 209458 b in optical/visible light using the CHEOPS space telescope. Our measurement of 20.4_–3.3^+3.2 parts per million translates into a geometric albedo of A_g = 0.096 ± 0.016. The previously estimated dayside temperature of about 1500 K implies that our geometric albedo measurement consists predominantly of reflected starlight and is largely uncontaminated by thermal emission. This makes the present result one of the most robust measurements of A_g for any exoplanet. Our calculations of the bandpass-integrated geometric albedo demonstrate that the measured value of A_g is consistent with a cloud-free atmosphere, where starlight is reflected via Rayleigh scattering by hydrogen molecules, and the water and sodium abundances are consistent with stellar metallicity. We predict that the bandpass-integrated TESS geometric albedo is too faint to detect and that a phase curve of HD 209458 b observed by CHEOPS would have a distinct shape associated with Rayleigh scattering if the atmosphere is indeed cloud free.

Abstract Copyright: © ESO 2022

Journal keyword(s): techniques: photometric - planetary systems - planets and satellites: atmospheres - planets and satellites: individual: HD 209458 b

VizieR on-line data: <Available at CDS (J/A+A/659/L4): table.dat table1.dat>

Simbad objects: 3

Full paper

View the references in ADS

Number of rows : 3

N	Identifier	Otype	ICRS (J2000) RA	ICRS (J2000) DEC	Sp type	#ref 1850 - 2023	#notes
1	Kepler-7b	Pl	19 14 19.5623271934	+41 05 23.365460942	~	194	1
2	HD 189733b	Pl	20 00 43.7130382888	+22 42 39.071811263	~	1348	1
3	HD 209458b	Pl	22 03 10.7729598762	+18 53 03.548248479	~	1773	1

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