Detection of transits of the nearby hot Neptune GJ 436 b
Detection of transits of the nearby hot Neptune GJ 436 b
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DOI：
10.1051/0004-6361:20077799
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发表时间：
2007-05
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通讯作者：
M. Gillon;F. Pont;B. Demory;F. Mallmann;M. Mayor;T. Mazeh;D. Queloz;Avi Shporer;S. Udry;C. Geneve;U. Geneve;Switzerland;Institut d'Astrophysique et de Geophysique;U. Liege;Belgium;O. F. B. -. Ofxb;S. O. Physics;Astronomy;Raymond;Beverly Sackler Faculty of Exact Sciences;T. University;T. Aviv;Israel;Laboratoire d'astrophysique;E. P. F. Lausanne;Observatoire
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作者：
M. Gillon;F. Pont;B. Demory;F. Mallmann;M. Mayor;T. Mazeh;D. Queloz;Avi Shporer;S. Udry;C. Geneve;U. Geneve;Switzerland;Institut d'Astrophysique et de Geophysique;U. Liege;Belgium;O. F. B. -. Ofxb;S. O. Physics;Astronomy;Raymond;Beverly Sackler Faculty of Exact Sciences;T. University;T. Aviv;Israel;Laboratoire d'astrophysique;E. P. F. Lausanne;Observatoire
这封信报告了对围绕附近 M 矮星 GJ 436 运行的海王星质量行星凌日的光度检测。它是迄今为止检测到的距离最近、最小且质量最小的凌日行星。它的质量略大于海王星的质量，M = 22.6 ± 1.9 M⊕。凌日光变曲线的形状和深度表明，它正在其边缘附近穿过主星盘（撞击参数0.84±0.03），并且该行星的大小与天王星和海王星相当，R = 25 200 ± 2200 km = 3.95 ± 0.35 R⊕。因此，它的主要成分很可能是水冰。如果当前的行星结构模型是正确的，冰层顶部可能需要一个质量高达百分之十的 H/He 外层来解释观测到的半径。
This Letter reports on the photometric detection of transits of the Neptune-mass planet orbiting the nearby M-dwarf star GJ 436. It is by far the closest, smallest, and least massive transiting planet detected so far. Its mass is slightly larger than Neptune’s at M = 22.6 ± 1.9 M⊕. The shape and depth of the transit lightcurves show that it is crossing the host star disc near its limb (impact parameter 0.84 ± 0.03) and that the planet size is comparable to that of Uranus and Neptune, R = 25 200 ± 2200 km = 3.95 ± 0.35 R⊕. Its main constituant is therefore very likely to be water ice. If the current planet structure models are correct, an outer layer of H/He constituting up to ten percent in mass is probably needed on top of the ice to account for the observed radius.