2020A&A...643A..94L

Query : 2020A&A...643A..94L

2020A&A...643A..94L - Astronomy and Astrophysics, volume 643A, 94-94 (2020/11-1)

The hot dayside and asymmetric transit of WASP-189 b seen by CHEOPS.

LENDL M., CSIZMADIA S., DELINE A., FOSSATI L., KITZMANN D., HENG K., HOYER S., SALMON S., BENZ W., BROEG C., EHRENREICH D., FORTIER A., QUELOZ D., BONFANTI A., BRANDEKER A., COLLIER CAMERON A., DELREZ L., GARCIA MUNOZ A., HOOTON M.J., MAXTED P.F.L., MORRIS B.M., VAN GROOTEL V., WILSON T.G., ALIBERT Y., ALONSO R., ASQUIER J., BANDY T., BARCZY T., BARRADO D., BARROS S.C.C., BAUMJOHANN W., BECK M., BECK T., BEKKELIEN A., BERGOMI M., BILLOT N., BIONDI F., BONFILS X., BOURRIER V., BUSCH M.-D., CABRERA J., CESSA V., CHARNOZ S., CHAZELAS B., CORRAL VAN DAMME C., DAVIES M.B., DELEUIL M., DEMANGEON O.D.S., DEMORY B.-O., ERIKSON A., FARINATO J., FRIDLUND M., FUTYAN D., GANDOLFI D., GILLON M., GUTERMAN P., HASIBA J., HERNANDEZ E., ISAAK K.G., KISS L., KUNTZER T., LECAVELIER DES ETANGS A., LUFTINGER T., LASKAR J., LOVIS C., MAGRIN D., MALVASIO L., MARAFATTO L., MICHAELIS H., MUNARI M., NASCIMBENI V., OLOFSSON G., OTTACHER H., OTTENSAMER R., PAGANO I., PALLE E., PETER G., PIAZZA D., PIOTTO G., POLLACCO D., RATTI F., RAUER H., RAGAZZONI R., RANDO N., RIBAS I., RIEDER M., ROHLFS R., SAFA F., SANTOS N.C., SCANDARIATO G., SEGRANSAN D., SIMON A.E., SINGH V., SMITH A.M.S., SORDET M., SOUSA S.G., STELLER M., SZABO G.M., THOMAS N., TSCHENTSCHER M., UDRY S., VIOTTO V., WALTER I., WALTON N.A., WILDI F. and WOLTER D.

Abstract (from CDS):

The CHEOPS space mission dedicated to exoplanet follow-up was launched in December 2019, equipped with the capacity to perform photometric measurements at the 20 ppm level. As CHEOPS carries out its observations in a broad optical passband, it can provide insights into the reflected light from exoplanets and constrain the short-wavelength thermal emission for the hottest of planets by observing occultations and phase curves. Here, we report the first CHEOPS observation of an occultation, namely, that of the hot Jupiter WASP-189 b, a M_P≃2M_J planet orbiting an A-type star. We detected the occultation of WASP-189 b at high significance in individual measurements and derived an occultation depth of dF=87.9±4.3ppm based on four occultations. We compared these measurements to model predictions and we find that they are consistent with an unreflective atmosphere heated to a temperature of 3435±27K, when assuming inefficient heat redistribution. Furthermore, we present two transits of WASP-189 b observed by CHEOPS. These transits have an asymmetric shape that we attribute to gravity darkening of the host star caused by its high rotation rate. We used these measurements to refine the planetary parameters, finding a ∼25% deeper transit compared to the discovery paper and updating the radius of WASP-189 b to 1.619±0.021R_J. We further measured the projected orbital obliquity to be λ=86.4_–4.4^+2.9°, a value that is in good agreement with a previous measurement from spectroscopic observations, and derived a true obliquity of Ψ=85.4±4.3°. Finally, we provide reference values for the photometric precision attained by the CHEOPS satellite: for the V=6.6mag star, and using a 1-h binning, we obtain a residual RMS between 10 and 17ppm on the individual light curves, and 5.7ppm when combining the four visits.

Abstract Copyright: © ESO 2020

Journal keyword(s): techniques: photometric - planets and satellites: atmospheres - planets and satellites: individual: WASP-189 b

VizieR on-line data: <Available at CDS (J/A+A/643/A94): 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	Mag B	Mag V	Sp type	#ref 1850 - 2023
1	HD 133112	PM*	15 02 44.8678907928	-03 01 52.986571896	6.788	6.618	A4/5IV/V	55
2	WASP-189b	Pl?	15 02 44.8679915475	-03 01 52.986005307			~	63
3	HD 195689b	Pl	20 31 26.3534038246	+39 56 19.765154336			~	235

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