Statistical analysis of exoplanet surveys

DOI

We conduct a statistical analysis of a combined sample of direct imaging data, totalling nearly 250 stars. The stars cover a wide range of ages and spectral types, and include five detections ({kappa} And b, two ~60 M_J_ brown dwarf companions in the Pleiades, PZ Tel B, and CD-35 2722B). For some analyses we add a currently unpublished set of SEEDS observations, including the detections GJ 504b and GJ 758B. We conduct a uniform, Bayesian analysis of all stellar ages using both membership in a kinematic moving group and activity/rotation age indicators. We then present a new statistical method for computing the likelihood of a substellar distribution function. By performing most of the integrals analytically, we achieve an enormous speedup over brute-force Monte Carlo. We use this method to place upper limits on the maximum semimajor axis of the distribution function derived from radial-velocity planets, finding model-dependent values of ~30-100 AU. Finally, we model the entire substellar sample, from massive brown dwarfs to a theoretically motivated cutoff at ~5 M_J_, with a single power-law distribution. We find that p(M,a){prop.to}M^-0.65+/-0.60^a^-0.85+/-0.39^ (1{sigma} errors) provides an adequate fit to our data, with 1.0%-3.1% (68% confidence) of stars hosting 5-70 M_J_ companions between 10 and 100 AU. This suggests that many of the directly imaged exoplanets known, including most (if not all) of the low-mass companions in our sample, formed by fragmentation in a cloud or disk, and represent the low-mass tail of the brown dwarfs.

Cone search capability for table J/ApJ/794/159/table2 (Age Distributions of All Targets)

Identifier
DOI http://doi.org/10.26093/cds/vizier.17940159
Source https://dc.g-vo.org/rr/q/lp/custom/CDS.VizieR/J/ApJ/794/159
Related Identifier https://cdsarc.cds.unistra.fr/viz-bin/cat/J/ApJ/794/159
Related Identifier http://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/ApJ/794/159
Metadata Access http://dc.g-vo.org/rr/q/pmh/pubreg.xml?verb=GetRecord&metadataPrefix=oai_b2find&identifier=ivo://CDS.VizieR/J/ApJ/794/159
Provenance
Creator Brandt T.D.; McElwain M.W.; Turner E.L.; Mede K.; Spiegel D.S.,Kuzuhara M.; Schlieder J.E.; Wisniewski J.P.; Abe L.; Biller B.,Brandner W.; Carson J.; Currie T.; Egner S.; Feldt M.; Golota T.; Goto M.,Grady C.A.; Guyon O.; Hashimoto J.; Hayano Y.; Hayashi M.; Hayashi S.,Henning T.; Hodapp K.W.; Inutsuka S.; Ishii M.; Iye M.; Janson M.,Kandori R.; Knapp G.R.; Kudo T.; Kusakabe N.; Kwon J.; Matsuo T.,Miyama S.; Morino J.-I.; Moro-Martin A.; Nishimura T.; Pyo T.-S.,Serabyn E.; Suto H.; Suzuki R.; Takami M.; Takato N.; Terada H.,Thalmann C.; Tomono D.; Watanabe M.; Yamada T.; Takami H.; Usuda T.,Tamura M.
Publisher CDS
Publication Year 2017
Rights https://cds.unistra.fr/vizier-org/licences_vizier.html
OpenAccess true
Contact CDS support team <cds-question(at)unistra.fr>
Representation
Resource Type Dataset; AstroObjects
Discipline Astrophysics and Astronomy; Natural Sciences; Physics; Solar System Astronomy; Stellar Astronomy