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arXiv 2107.03802astro-ph.EP
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CARMENES搜寻M矮星周围的系外行星--来自71颗恒星子样本的行星出现率

The CARMENES search for exoplanets around M dwarfs -- Planet occurrence rates from a subsample of 71 stars

S. Sabotta, M. Schlecker, P. Chaturvedi, E. W. Guenther, I. Muñoz Rodríguez, J. C. Muñoz Sánchez, J. A. Caballero, Y. Shan, S. Reffert, I. Ribas, A. Reiners, A.… 展开作者

S. Sabotta, M. Schlecker, P. Chaturvedi, E. W. Guenther, I. Muñoz Rodríguez, J. C. Muñoz Sánchez, J. A. Caballero, Y. Shan, S. Reffert, I. Ribas, A. Reiners, A. P. Hatzes, P. J. Amado, H. Klahr, J. C. Morales, A. Quirrenbach, Th. Henning, S. Dreizler, E. Pallé, M. Perger, M. Azzaro, S. V. Jeffers, A. Kaminski, M. Kürster, M. Lafarga, D. Montes, V. M. Passegger, M. Zechmeister

摘要:

在过去的五年里,作为保证时间观测(GTO)计划的一部分,CARMENES M矮星系外行星调查已经获得了329个附近M矮星的18000多个光谱。我们确定行星的出现率与71颗恒星从GTO计划,我们有超过50个观测。我们使用注入和检索实验的径向速度(RV)的时间序列来衡量检测概率。我们的分析包括21个行星系中的27颗行星。我们发现每颗恒星有0.06+0.04-0.03颗巨行星(100 M_Earth < M_pl sin i < 1000 M_Earth),周期长达1000 d,但由于选择偏差,在整个329颗恒星样本中,这个数字可能会低五倍。热行星(轨道周期小于10 d)的上限是每颗恒星0.03颗行星,而中等质量行星(10 M_Earth < M_pl sin i < 100 M_Earth)的出现率是每颗恒星0.18+0.07-0.05颗行星。质量小于1 M_Earth < M_pl sin i < 10 M_Earth的行星非常丰富,估计每颗恒星的行星数为1.32+0.33-0.31,周期可达100 d。当只考虑质量M_star < 0.34 M_sol的晚M矮星时,质量超过10 M_Earth的行星变得罕见。相反,周期短于10 d的低质量行星明显过剩。对于小于100 d的轨道周期,我们的结果证实了开普勒巡天中已知的恒星质量依赖性:M矮星比G型星拥有更少的巨行星,而M_pl sin i < 10 M_Earth的行星至少是G型星的两倍。与以前的结果相反,我们的样本非常低质量的恒星周围的行星在短周期轨道小于10 d的出现率更高。我们的研究结果表明,需要考虑主机恒星质量的行星形成模型。

英文摘要:

The CARMENES exoplanet survey of M dwarfs has obtained more than 18 000 spectra of 329 nearby M dwarfs over the past five years as part of its guaranteed time observations (GTO) program. We determine planet occurrence rates with the 71 stars from the GTO program for which we have more than 50 observations. We use injection-and-retrieval experiments on the radial-velocity (RV) time series to measure detection probabilities. We include 27 planets in 21 planetary systems in our analysis. We find 0.06+0.04-0.03 giant planets (100 M_Earth < M_pl sin i < 1000 M_Earth) per star in periods of up to 1000 d, but due to a selection bias this number could be up to a factor of five lower in the whole 329-star sample. The upper limit for hot Jupiters (orbital period of less than 10 d) is 0.03 planets per star, while the occurrence rate of planets with intermediate masses (10 M_Earth < M_pl sin i < 100 M_Earth) is 0.18+0.07-0.05 planets per star. Less massive planets with 1 M_Earth < M_pl sin i < 10 M_Earth are very abundant, with an estimated rate of 1.32+0.33-0.31 planets per star for periods of up to 100 d. When considering only late M dwarfs with masses M_star < 0.34 M_sol, planets more massive than 10 M_Earth become rare. Instead, low-mass planets with periods shorter than 10 d are significantly overabundant. For orbital periods shorter than 100 d, our results confirm the known stellar mass dependences from the Kepler survey: M dwarfs host fewer giant planets and at least two times more planets with M_pl sin i < 10 M_Earth than G-type stars. In contrast to previous results, planets around our sample of very low-mass stars have a higher occurrence rate in short-period orbits of less than 10 d. Our results demonstrate the need to take into account host star masses in planet formation models.

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