The discoveries of WASP-91b, WASP-105b and WASP-107b: two warm Jupiters and a planet in the transition region between ice giants and gas giants-猫眼课题宝

DOI：

10.1051/0004-6361/201730439

发表时间：

2017-01

期刊：

arXiv: Earth and Planetary Astrophysics

影响因子：

通讯作者：

中科院分区：

其他

文献类型：

作者：

D. Anderson;A. Cameron;L. Delrez;A. Doyle;M. Gillon;C. Hellier;E. Jehin;M. Lendl;P. Maxted;N. Madhusudhan;F. Pepe;D. Pollacco;D. Queloz;D. Ségransan;B. Smalley;Alexis M. S. Smith;A. Triaud;O. Turner;S. Udry;R. West

我们报告三个凌日系外行星的发现。WASP-91 b是一颗温暖的木星（1.34 $M_{\rm Jup}$，1.03 $R_{\rm Jup}$），环绕一颗富含金属的K3星星运行2.8天。WASP-105 b是一颗温暖的木星（1.8 $M_{\rm Jup}$，0.96 $R_{\rm Jup}$），环绕一颗富含金属的K2星星运行7.9天。WASP-107 b是一颗温暖的超海王星/次土星（0.12 $M_{\rm Jup}$，0.94 $R_{\rm Jup}$），围绕太阳金属丰度为K6的星星运行5.7天。考虑到巨行星似乎更常见于高金属量的恒星和更大质量的恒星周围，值得注意的是，宿主都是富含金属的晚型恒星。由于WASP-105 b和WASP-107 b的轨道分离都处于弱潮汐状态，因此测量行星轨道轴与恒星自旋轴之间的对齐可能有助于我们理解短周期巨行星的向内迁移。WASP-107 b的质量（2.2 $M_{\rm Nep}$，0.40 $M_{\rm Sat}$）使其位于太阳系中冰巨星和气体巨星之间的过渡区域。它的半径为0.94 $R_{\rm Jup}$，表明它是一个低质量的气体巨星，具有H/He占主导地位的成分。因此，这颗行星设定了一个行星质量的下限2.2 $M_{\rm Nep}$，超过这个下限，大的气体包层可以被原行星吸积并保留下来，从而成为气体巨星。我们可能会发现WASP-107 b是否更像一个冰巨星或气体巨星，通过测量其大气金属含量通过透射光谱，其中WASP-107 b是一个非常好的目标。

We report the discoveries of three transiting exoplanets. WASP-91b is a warm Jupiter (1.34 $M_{\rm Jup}$, 1.03 $R_{\rm Jup}$) in a 2.8-day orbit around a metal-rich K3 star. WASP-105b is a warm Jupiter (1.8 $M_{\rm Jup}$, 0.96 $R_{\rm Jup}$) in a 7.9-day orbit around a metal-rich K2 star. WASP-107b is a warm super-Neptune/sub-Saturn (0.12 $M_{\rm Jup}$, 0.94 $R_{\rm Jup}$) in a 5.7-day orbit around a solar-metallicity K6 star. Considering that giant planets seem to be more common around stars of higher metallicity and stars of higher mass, it is notable that the hosts are all metal-rich, late-type stars. With orbital separations that place both WASP-105b and WASP-107b in the weak-tide regime, measurements of the alignment between the planets' orbital axes and their stars' spin axes may help us to understand the inward migration of short-period, giant planets. The mass of WASP-107b (2.2 $M_{\rm Nep}$, 0.40 $M_{\rm Sat}$) places it in the transition region between the ice giants and gas giants of the Solar System. Its radius of 0.94 $R_{\rm Jup}$ suggests that it is a low-mass gas giant with a H/He-dominated composition. The planet thus sets a lower limit of 2.2 $M_{\rm Nep}$ on the planetary mass above which large gaseous envelopes can be accreted and retained by proto-planets on their way to becoming gas giants. We may discover whether WASP-107b more closely resembles an ice giant or a gas giant by measuring its atmospheric metallicity via transmission spectroscopy, for which WASP-107b is a very good target.

The discoveries of WASP-91b, WASP-105b and WASP-107b: two warm Jupiters and a planet in the transition region between ice giants and gas giants

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