arXivDaily arXiv每日学术速递 周一至周五更新
arXiv 1008.5232astro-ph.EP
收藏

低质量系外行星的频率。II。“时代谷”

The Frequency of Low-Mass Exoplanets. II. The `Period Valley'

Robert A. Wittenmyer, Simon J. O'Toole, H. R. A. Jones, C. G. Tinney, R. P. Butler, B. D. Carter, J. Bailey

备注：
ApJ, accepted
阅读 PDF
arXiv 页面 ↗HTML 原文 ↗

摘要：

径向速度行星搜索运动现在开始探测低质量的“超级地球”行星，最小质量M sin i < 10 M_地球。使用两种独立开发的方法，我们从英澳行星搜索计划中24颗明亮、稳定恒星近四年的最高精度数据中推导出了检测限。这两种方法都比人类分析单个观测数据集更保守，这两种技术都可以在50%的试验中检测到宣布为61 Vir系统系外行星的径向速度信号。这两种方法之间有一些差别，可以认为是由于它们所采用的特定标准而产生的。这两个过程提供的是一个定量的选择过程，这样人们就可以使用它们从给定的数据集得出关于行星频率和轨道参数分布的定量结论。平均所有24颗恒星，在周期范围P<300天和偏心率范围0.0<e<0.6，我们可以检测到99%的行星速度振幅K>7.1 m/s。对于样本中最好的恒星，我们能够检测或排除K>3 m/s的行星，对应于8 M_地球（P=5天）或17 M_地球（P=50天）的最小质量。我们的研究结果表明，观察到的“周期谷”，即缺乏周期在10-100天之间的巨行星（M>100 M_地球），确实是真实的。然而，对于质量范围为10-100 M_earth的行星，我们的结果表明，这类行星的赤字可能是选择效应的结果。

英文摘要：

Radial-velocity planet search campaigns are now beginning to detect low-mass "Super-Earth" planets, with minimum masses M sin i < 10 M_earth. Using two independently-developed methods, we have derived detection limits from nearly four years of the highest-precision data on 24 bright, stable stars from the Anglo-Australian Planet Search. Both methods are more conservative than a human analysing an individual observed data set, as is demonstrated by the fact that both techniques would detect the radial velocity signals announced as exoplanets for the 61 Vir system in 50% of trials. There are modest differences between the methods which can be recognised as arising from particular criteria that they adopt. What both processes deliver is a quantitative selection process such that one can use them to draw quantitative conclusions about planetary frequency and orbital parameter distribution from a given data set. Averaging over all 24 stars, in the period range P<300 days and the eccentricity range 0.0<e<0.6, we could have detected 99% of planets with velocity amplitudes K>7.1 m/s. For the best stars in the sample, we are able to detect or exclude planets with K>3 m/s, corresponding to minimum masses of 8 M_earth (P=5 days) or 17 M_earth (P=50 days). Our results indicate that the observed "period valley," a lack of giant planets (M>100 M_earth) with periods between 10-100 days, is indeed real. However, for planets in the mass range 10-100 M_earth, our results suggest that the deficit of such planets may be a result of selection effects.

机构、总结、中文摘要均由AI分析而来，可能存在错误，请以论文正文为准。

↑