Skip navigation
Skip navigation

Discovery of a cool planet of 5.5 Earth masses through gravitational microlensing

Beaulieu, J.-P; Bennett, D P; Fouque, P; Williams, Andrew; Sackett, Penny; Dominik, M; Jorgensen, U G; Kubas, D; Cassan, A; Coutures, C; Greenhill, J; Hearnshaw, J B; Hill, Kym

Description

In the favoured core-accretion model of formation of planetary systems, solid planetesimals accumulate to build up planetary cores, which then accrete nebular gas if they are sufficiently massive. Around M-dwarf stars (the most common stars in our Galaxy), this model favours the formation of Earth-mass (M ⊕) to Neptune-mass planets with orbital radii of 1 to 10 astronomical units (AU), which is consistent with the small number of gas giant planets known to orbit M-dwarf host stars 1-4. More...[Show more]

dc.contributor.authorBeaulieu, J.-P
dc.contributor.authorBennett, D P
dc.contributor.authorFouque, P
dc.contributor.authorWilliams, Andrew
dc.contributor.authorSackett, Penny
dc.contributor.authorDominik, M
dc.contributor.authorJorgensen, U G
dc.contributor.authorKubas, D
dc.contributor.authorCassan, A
dc.contributor.authorCoutures, C
dc.contributor.authorGreenhill, J
dc.contributor.authorHearnshaw, J B
dc.contributor.authorHill, Kym
dc.date.accessioned2015-12-07T22:13:36Z
dc.identifier.issn0028-0836
dc.identifier.urihttp://hdl.handle.net/1885/17086
dc.description.abstractIn the favoured core-accretion model of formation of planetary systems, solid planetesimals accumulate to build up planetary cores, which then accrete nebular gas if they are sufficiently massive. Around M-dwarf stars (the most common stars in our Galaxy), this model favours the formation of Earth-mass (M ⊕) to Neptune-mass planets with orbital radii of 1 to 10 astronomical units (AU), which is consistent with the small number of gas giant planets known to orbit M-dwarf host stars 1-4. More than 170 extrasolar planets have been discovered with a wide range of masses and orbital periods, but planets of Neptune's mass or less have not hitherto been detected at separations of more than 0.15 AU from normal stars. Here we report the discovery of a 5.5 -2.7+5.5 M ⊕ planetary companion at a separation of 2.6 -0.6+1.5 AU from a 0.22 -0.11+0.21 M ⊙ M-dwarf star, where M ⊙ refers to a solar mass. (We propose to name it OGLE-2005-BLG-390Lb, indicating a planetary mass companion to the lens star of the microlensing event.) The mass is lower than that of GJ876d (ref. 5), although the error bars overlap. Our detection suggests that such cool, sub-Neptune-mass planets may be more common than gas giant planets, as predicted by the core accretion theory.
dc.publisherMacmillan Publishers Ltd
dc.sourceNature
dc.subjectKeywords: Accretion; Gravitation microlensing; M-dwarf stars; Planetesimals; Astronomy; Gravitation; Mathematical models; Orbits; Planets; astronomy; article; astronomy; cosmos; gas; gravity; molecular weight; priority journal; theoretical study
dc.titleDiscovery of a cool planet of 5.5 Earth masses through gravitational microlensing
dc.typeJournal article
local.description.notesImported from ARIES
local.identifier.citationvolume439
dc.date.issued2006
local.identifier.absfor020110 - Stellar Astronomy and Planetary Systems
local.identifier.ariespublicationU1408929xPUB1
local.type.statusPublished Version
local.contributor.affiliationBeaulieu, J.-P, Universite Pierre et Marie Curie (CRNS)
local.contributor.affiliationBennett, D P, University of Notre Dame
local.contributor.affiliationFouque, P, Observatoire Midi-Pyrenees
local.contributor.affiliationWilliams, Andrew, Perth Observatory
local.contributor.affiliationSackett, Penny, College of Physical and Mathematical Sciences, ANU
local.contributor.affiliationDominik, M, University of St Andrews
local.contributor.affiliationJorgensen, U G, University of Copenhagen
local.contributor.affiliationKubas, D, European Southern Observatory
local.contributor.affiliationCassan, A, Institut d'Astrophysique de Paris
local.contributor.affiliationCoutures, C, CEA-Saclay
local.contributor.affiliationGreenhill, J, University of Tasmania
local.contributor.affiliationHearnshaw, J B, University of Canterbury
local.contributor.affiliationHill, Kym, University of Tasmania
local.description.embargo2037-12-31
local.bibliographicCitation.issue26 January 2006
local.bibliographicCitation.startpage437
local.bibliographicCitation.lastpage440
local.identifier.doi10.1038/nature04441
dc.date.updated2015-12-07T07:17:42Z
local.identifier.scopusID2-s2.0-31444432828
CollectionsANU Research Publications

Download

File Description SizeFormat Image
01_Beaulieu_Discovery_of_a_cool_planet_of_2006.pdf275.82 kBAdobe PDF    Request a copy


Items in Open Research are protected by copyright, with all rights reserved, unless otherwise indicated.

Updated:  17 November 2022/ Responsible Officer:  University Librarian/ Page Contact:  Library Systems & Web Coordinator