Publication Date:
2016-07-09
Description:
With the progress of detection techniques, the number of low-mass and small-size exoplanets is increasing rapidly. However their characteristics and formation mechanisms are not yet fully understood. The metallicity of the host star is a critical parameter in such processes and can impact the occurrence rate or physical properties of these planets. While a frequency–metallicity correlation has been found for giant planets, this is still an ongoing debate for their smaller counterparts. Using the published parameters of a sample of 157 exoplanets lighter than 40 M , we explore the mass-metallicity space of Neptunes and super-Earths. We show the existence of a maximal mass that increases with metallicity, that also depends on the period of these planets. This seems to favour in situ formation or alternatively a metallicity-driven migration mechanism. It also suggests that the frequency of Neptunes (between 10 and 40 M ) is, like giant planets, correlated with the host star metallicity, whereas no correlation is found for super-Earths (〈10 M ).
Print ISSN:
0035-8711
Electronic ISSN:
1365-2966
Topics:
Physics
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