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One or more bound planets per Milky Way star from microlensing observations
journal contribution
posted on 2023-05-17, 12:30 authored by Cassan, A, Kubas, D, Jean-Philippe BeaulieuJean-Philippe Beaulieu, Dominik, M, Horne, K, Greenhill, JG, Wambsganss, J, Menzies, J, Williams, A, Jorgensen, UG, Udalski, A, Bennett, DP, Albrow, MD, Batista, V, Brillant, S, Caldwell, JAR, Andrew ColeAndrew Cole, Coutures, C, Cook, KH, Dieters, S, Prester, DD, Donatowicz, J, Fouque, P, Kym HillKym Hill, Kains, N, Kane, S, Marquette, JB, Martin, R, Pollard, KR, Sahu, KC, Vinter, C, David WarrenDavid Warren, Watson, RD, Zub, M, Sumi, T, Szymanski, MK, Kubiak, M, Poleski, R, Soszynski, I, Ulaczyk, K, Pietrzynski, G, Wyrzykowski, LMost known extrasolar planets (exoplanets) have been discovered using the radial velocity or transit methods. Both are biased towards planets that are relatively close to their parent stars, and studies find that around 17–30% of solar-like stars host a planet. Gravitational microlensing, on the other hand, probes planets that are further away from their stars. Recently, a population of planets that are unbound or very far from their stars was discovered by microlensing. These planets are at least as numerous as the stars in the Milky Way. Here we report a statistical analysis of microlensing data (gathered in 2002–07) that reveals the fraction of bound planets 0.5–10 AU (Sun–Earth distance) from their stars. We find that 17+6-9% of stars host Jupiter-mass planets (0.3–10 MJ,where MJ = 318 M⊕ and M⊕ is Earth’s mass). Cool Neptunes (10–30 M⊕) and super-Earths (5–10 M⊕) are even more common: their respective abundances per star are 52+22-29% and 62+35-37%. We conclude that stars are orbited by planets as a rule, rather than the exception.
History
Publication title
NatureVolume
481Issue
7380Pagination
167-169ISSN
0028-0836Department/School
School of Natural SciencesPublisher
Nature Publishing GroupPlace of publication
Macmillan Building, 4 Crinan St, London, England, N1 9XwRights statement
Copyright 2012 Macmillan Publishers LimitedRepository Status
- Restricted