Skip to main page content
Access keys NCBI Homepage MyNCBI Homepage Main Content Main Navigation
, 481 (7380), 167-9

One or More Bound Planets Per Milky Way Star From Microlensing Observations

Affiliations

One or More Bound Planets Per Milky Way Star From Microlensing Observations

A Cassan et al. Nature.

Abstract

Most 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% (refs 4, 5) 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 M(J), where M(J) = 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.

Similar articles

  • Occurrence and core-envelope structure of 1-4× Earth-size planets around Sun-like stars.
    Marcy GW, Weiss LM, Petigura EA, Isaacson H, Howard AW, Buchhave LA. Marcy GW, et al. Proc Natl Acad Sci U S A. 2014 Sep 2;111(35):12655-60. doi: 10.1073/pnas.1304197111. Epub 2014 May 27. Proc Natl Acad Sci U S A. 2014. PMID: 24912169 Free PMC article.
  • Discovery of a cool planet of 5.5 Earth masses through gravitational microlensing.
    Beaulieu JP, Bennett DP, Fouqué P, Williams A, Dominik M, Jørgensen UG, Kubas D, Cassan A, Coutures C, Greenhill J, Hill K, Menzies J, Sackett PD, Albrow M, Brillant S, Caldwell JA, Calitz JJ, Cook KH, Corrales E, Desort M, Dieters S, Dominis D, Donatowicz J, Hoffman M, Kane S, Marquette JB, Martin R, Meintjes P, Pollard K, Sahu K, Vinter C, Wambsganss J, Woller K, Horne K, Steele I, Bramich DM, Burgdorf M, Snodgrass C, Bode M, Udalski A, Szymański MK, Kubiak M, Wieckowski T, Pietrzyński G, Soszyński I, Szewczyk O, Wyrzykowski L, Paczyński B, Abe F, Bond IA, Britton TR, Gilmore AC, Hearnshaw JB, Itow Y, Kamiya K, Kilmartin PM, Korpela AV, Masuda K, Matsubara Y, Motomura M, Muraki Y, Nakamura S, Okada C, Ohnishi K, Rattenbury NJ, Sako T, Sato S, Sasaki M, Sekiguchi T, Sullivan DJ, Tristram PJ, Yock PC, Yoshioka T. Beaulieu JP, et al. Nature. 2006 Jan 26;439(7075):437-40. doi: 10.1038/nature04441. Nature. 2006. PMID: 16437108
  • No large population of unbound or wide-orbit Jupiter-mass planets.
    Mróz P, Udalski A, Skowron J, Poleski R, Kozłowski S, Szymański MK, Soszyński I, Wyrzykowski Ł, Pietrukowicz P, Ulaczyk K, Skowron D, Pawlak M. Mróz P, et al. Nature. 2017 Aug 10;548(7666):183-186. doi: 10.1038/nature23276. Epub 2017 Jul 24. Nature. 2017. PMID: 28738410
  • M stars as targets for terrestrial exoplanet searches and biosignature detection.
    Scalo J, Kaltenegger L, Segura A, Fridlund M, Ribas I, Kulikov YN, Grenfell JL, Rauer H, Odert P, Leitzinger M, Selsis F, Khodachenko ML, Eiroa C, Kasting J, Lammer H. Scalo J, et al. Astrobiology. 2007 Feb;7(1):85-166. doi: 10.1089/ast.2006.0125. Astrobiology. 2007. PMID: 17407405 Review.
  • Spectral signatures of photosynthesis. II. Coevolution with other stars and the atmosphere on extrasolar worlds.
    Kiang NY, Segura A, Tinetti G, Govindjee, Blankenship RE, Cohen M, Siefert J, Crisp D, Meadows VS. Kiang NY, et al. Astrobiology. 2007 Feb;7(1):252-74. doi: 10.1089/ast.2006.0108. Astrobiology. 2007. PMID: 17407410 Review.
See all similar articles

Cited by 9 articles

See all "Cited by" articles

References

    1. Astrophys J. 2000 Jan 20;529(1):L45-L48 - PubMed
    1. Science. 2008 Feb 15;319(5865):927-30 - PubMed
    1. Science. 2010 Oct 29;330(6004):653-5 - PubMed
    1. Nature. 2006 Jan 26;439(7075):437-40 - PubMed
    1. Nature. 2011 May 19;473(7347):349-52 - PubMed

Publication types

LinkOut - more resources

Feedback