http://arxiv.org/abs/1806.08799
We use radial velocity observations to search for massive, long-period gas giant companions in systems hosting inner super-Earth (1-4 R_Earth, 1-10 M_Earth) planets in order to constrain formation and migration scenarios for this population. We consistently re-fit all published radial velocity datasets for a sample of 65 stars and find 9 systems with statistically significant trends indicating the presence of an outer companion. We combine these radial velocity data with AO images in order to constrain the allowed masses and semi-major axes of these companions. We quantify our sensitivity to the presence of long period companions by fitting the sample with a power law distribution and find an estimated occurrence rate of 39+/-7% for companions between 0.5-20 M_Jup and 1-20 AU. Half of our systems were discovered by the transit method and the other half were discovered by the RV method. While differences in RV baselines and number of data points between the two samples lead to different sensitivities to distant companions, we find that the occurrence rates of gas giant companions in each sample is consistent at the 0.5sigma level. We compare the frequency of Jupiter analogs in these systems to the equivalent rate from field star surveys and find that Jupiter analogs are more common around stars hosting super-Earths. We conclude that the presence of outer gas giant planets does not suppress the formation of inner super-Earths, and that these two populations of planets instead appear to be correlated with each other. We also find that the stellar metallicities of systems with gas giant companions are significantly higher than those without companions, in good agreement with the well-established metallicity correlation from RV surveys of field stars.
M. Bryan, H. Knutson, B. Fulton, et. al.
Tue, 26 Jun 18
47/71
Comments: 18 pages, 7 figures, submitted to AJ
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