文章基本信息

标题：Smaller than Expected Bright-spot Offsets in Spitzer Phase Curves of the Hot Jupiter Qatar-1b
本地全文：下载
作者：Dylan Keating ; Kevin B.Stevenson ; Nicolas B.Cowan 等
期刊名称：The Astronomical journal
印刷版ISSN：0004-6256
电子版ISSN：1538-3881
出版年度：2020
卷号：159
期号：5
页码：3094-3104
DOI：10.3847/1538-3881/ab83f4
语种：English
出版社：American Institute of Physics
摘要：We present Spitzer full-orbit thermal phase curves of the hot Jupiter Qatar-1b, a planet with the same equilibrium temperature—and intermediate surface gravity and orbital period—as the well-studied planets HD 209458b and WASP-43b.We measure secondary eclipse depths of 0.21 ± 0.02% at 3.6 μm and 0.30 ± 0.02% at 4.5 μm, corresponding to dayside brightness temperatures of ${1542}_{-31}^{+32}$ K and ${1557}_{-36}^{+35}$ K, respectively, consistent with a vertically isothermal dayside.The respective nightside brightness temperatures are ${1117}_{-71}^{+76}$ and ${1167}_{-74}^{+69}$ K, in line with a trend that hot Jupiters all have similar nightside temperatures.We infer a Bond albedo of ${0.12}_{-0.16}^{+0.14}$ and a moderate day–night heat recirculation efficiency, similar to HD 209458b.General circulation models for HD 209458b and WASP-43b predict that their bright spots should be shifted east of the substellar point by tens of degrees, and these predictions were previously confirmed with Spitzer full-orbit phase curve observations.The phase curves of Qatar-1b are likewise expected to exhibit eastward offsets.Instead, the observed phase curves are consistent with no offset: 11° ± 7° at 3.6 μm and −4° ± 7° at 4.5 μm.The discrepancy in circulation patterns between these three otherwise similar planets points to the importance of secondary parameters like rotation rate and surface gravity, and the presence or absence of clouds, in determining atmospheric conditions on hot Jupiters.
关键词：Extrasolar gas giants;Light curves;Hot Jupiters;Exoplanet atmospheres