WASP-17b: AN ULTRA-LOW DENSITY PLANET IN A PROBABLE RETROGRADE ORBIT-猫眼课题宝

DOI：

10.1088/0004-637x/709/1/159

发表时间：

2009-08

期刊：

The Astrophysical Journal

影响因子：

通讯作者：

中科院分区：

其他

文献类型：

作者：

D. Anderson;C. Hellier;M. Gillon;M. Gillon;A. Triaud;B. Smalley;L. Hebb;A. Cameron;P. Maxted;D. Queloz;R. West;S. Bentley;B. Enoch;K. Horne;T. Lister;M. Mayor;N. Parley;F. Pepe;D. Pollacco;D. Ségransan;S. Udry;D. Wilson;D. Wilson

我们报告发现了凌日巨行星WASP-17 b，这是目前已知的密度最小的行星。它的质量是土星的1.6倍，但半径是木星的1.5-2倍，密度是木星的6%-14%。WASP-17 b围绕一颗亚太阳金属量V = 11.6的F6星星运行3.7天。罗西特-麦克劳克林效应的初步探测显示WASP-17 b是在一个逆行的轨道（λ π −150°），显示了一个剧烈的历史，涉及行星与行星或恒星与行星的散射。WASP-17 b膨胀的半径可能是由于最近或正在进行的偏心轨道潮汐循环导致的潮汐加热，例如通常由散射相互作用导致的高度偏心轨道。因此，必须通过进一步的高精度径向速度测量或通过确定二次日食的时间，更精确地确定当前的轨道偏心率，以减少行星半径的不确定性并测试潮汐加热模型。由于其低表面重力，WASP-17 b的大气层具有任何已知行星中最大的尺度高度，使其成为透射光谱学的良好目标。

We report the discovery of the transiting giant planet WASP-17b, the least-dense planet currently known. It is 1.6 Saturn masses, but 1.5–2 Jupiter radii, giving a density of 6%–14% that of Jupiter. WASP-17b is in a 3.7 day orbit around a sub-solar metallicity, V = 11.6, F6 star. Preliminary detection of the Rossiter–McLaughlin effect suggests that WASP-17b is in a retrograde orbit (λ ≈ −150°), indicative of a violent history involving planet–planet or star–planet scattering. WASP-17b's bloated radius could be due to tidal heating resulting from recent or ongoing tidal circularization of an eccentric orbit, such as the highly eccentric orbits that typically result from scattering interactions. It will thus be important to determine more precisely the current orbital eccentricity by further high-precision radial velocity measurements or by timing the secondary eclipse, both to reduce the uncertainty on the planet's radius and to test tidal-heating models. Owing to its low surface gravity, WASP-17b's atmosphere has the largest scale height of any known planet, making it a good target for transmission spectroscopy.

WASP-17b: AN ULTRA-LOW DENSITY PLANET IN A PROBABLE RETROGRADE ORBIT

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