C.D.S. - SIMBAD4 rel 1.7 - 2020.04.04CEST18:27:32

2019A&A...625A.136A - Astronomy and Astrophysics, volume 625A, 136-136 (2019/5-1)

Climate of an ultra hot Jupiter. Spectroscopic phase curve of WASP-18b with HST/WFC3.


Abstract (from CDS):

We present the analysis of a full-orbit, spectroscopic phase curve of the ultra hot Jupiter (UHJ) WASP-18b, obtained with the Wide Field Camera 3 aboard the Hubble Space Telescope. We measured the normalised day-night contrast of the planet as >0.96 in luminosity: the disc-integrated dayside emission from the planet is at 964±25ppm, corresponding to 2894±30K, and we place an upper limit on the nightside emission of <32ppm or 1430K at the 3σ level. We also find that the peak of the phase curve exhibits a small, but significant offset in brightness of 4.5±0.5° eastward. We compare the extracted phase curve and phase-resolved spectra to 3D global circulation models and find that broadly the data can be well reproduced by some of these models. We find from this comparison several constraints on the atmospheric properties of the planet. Firstly we find that we need efficient drag to explain the very inefficient day-night recirculation observed. We demonstrate that this drag could be due to Lorentz-force drag by a magnetic field as weak as 10 gauss. Secondly, we show that a high metallicity is not required to match the large day-night temperature contrast. In fact, the effect of metallicity on the phase curve is different from cooler gas-giant counterparts because of the high-temperature chemistry in the atmosphere of WASP-18b. Additionally, we compared the current UHJ spectroscopic phase curves, WASP-18b and WASP-103b, and show that these two planets provide a consistent picture with remarkable similarities in their measured and inferred properties. However, key differences in these properties, such as their brightness offsets and radius anomalies, suggest that UHJ could be used to separate between competing theories for the inflation of gas-giant planets.

Abstract Copyright: © ESO 2019

Journal keyword(s): planets and satellites: atmospheres

VizieR on-line data: <Available at CDS (J/A+A/625/A136): w114_117.dat w117_121.dat w121_124.dat w124_127.dat w127_130.dat w130_134.dat w134_137.dat w137_140.dat w140_144.dat w144_147.dat w147_150.dat w150_153.dat w153_157.dat w157_160.dat>

Status at CDS:  

Simbad objects: 8

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Number of rows : 8

N Identifier Otype ICRS (J2000)
ICRS (J2000)
Mag U Mag B Mag V Mag R Mag I Sp type #ref
1850 - 2020
1 HD 10069 * 01 37 25.0335097438 -45 40 40.376513381   9.74 9.30     F6IV/V 145 1
2 WASP-18b Pl 01 37 25.0335097438 -45 40 40.376513381           ~ 200 1
3 WASP-43b Pl 10 19 38.0089444408 -09 48 22.603103969           ~ 183 1
4 WASP-103b Pl 16 37 15.5753608801 +07 11 00.119024745           ~ 73 1
5 WASP-103 * 16 37 15.5753608801 +07 11 00.119024745     12.1     F8V 30 1
6 CoRoT-2b Pl 19 27 06.4944821296 +01 23 01.357597206     12.57     ~ 174 1
7 KOI-2.01 Pl 19 28 59.3538131541 +47 58 10.216250846           ~ 259 1
8 HD 209458b Pl 22 03 10.7729598762 +18 53 03.548248479           ~ 1440 1

    Equat.    Gal    SGal    Ecl

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