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dc.contributor.authorWeights, D.
dc.contributor.authorLucas, P.W.
dc.contributor.authorRoche, P.F.
dc.contributor.authorPinfield, D.J.
dc.contributor.authorRiddick, F.
dc.date.accessioned2009-06-30T07:34:38Z
dc.date.available2009-06-30T07:34:38Z
dc.date.issued2009
dc.identifier.citationWeights , D , Lucas , P W , Roche , P F , Pinfield , D J & Riddick , F 2009 , ' Infrared spectroscopy and analysis of brown dwarf and planetary mass objects in the Orion nebula cluster ' Monthly Notices of the Royal Astronomical Society , vol. 392 , no. 2 , pp. 817-846 . https://doi.org/10.1111/j.1365-2966.2008.14096.x
dc.identifier.issn0035-8711
dc.identifier.otherPURE: 139336
dc.identifier.otherPURE UUID: 05c1139e-d441-4f5f-bf98-a6de6bc3c384
dc.identifier.otherdspace: 2299/3632
dc.identifier.otherScopus: 58049178140
dc.identifier.urihttp://hdl.handle.net/2299/3632
dc.description‘The definitive version is available at www3.interscience.wiley.com '. Copyright Blackwell Publishing / Royal Astronomical Society. DOI: 10.1111/j.1365-2966.2008.14096.x
dc.description.abstractWe present near-infrared long-slit and multislit spectra of low-mass brown dwarf candidates in the Orion nebula cluster. The long-slit data were observed in the H and K bands using NIRI on the Gemini-North Telescope. The multi-object spectroscopic observations were made using IRIS2 on the Anglo-Australian Telescope at H band. We develop a spectral typing scheme based on optically calibrated, near-infrared spectra of young sources in the Taurus and IC 348 star-forming regions with spectral types M3.0 to M9.5. We apply our spectral typing scheme to 52 sources, including previously published UKIRT and GNIRS spectra. 40 objects show strong water absorption with spectral types of M3 to >M9.5. The latest type objects are provisionally classified as early L types. We plot our sources on Hertzsprung–Russell diagrams overlaid with theoretical pre-main-sequence isochrones. The majority of our objects lie close to or above the 1-Myr isochrone, leading to an average cluster age that is <1 Myr. We find 38 sources lie at or below the hydrogen-burning limit (0.075 M⊙). 10 sources potentially have masses below the deuterium-burning limit (0.012 M⊙). We use a Monte Carlo approach to model the observed luminosity function with a variety of cluster age and mass distributions. The lowest χ2 values are produced by an age distribution centred at 1 Myr, with a mass function that declines at substellar masses according to an Mα power law in the range α= 0.3–0.6. We find that truncating the mass function at 0.012 M⊙ produces luminosity functions that are starved of the faintest magnitudes, even when using bimodal age populations that contain 10-Myr-old sources. The results of these Monte Carlo simulations therefore support the existence of a planetary mass population in the ONCen
dc.language.isoeng
dc.relation.ispartofMonthly Notices of the Royal Astronomical Society
dc.rights/dk/atira/pure/core/openaccesspermission/open
dc.titleInfrared spectroscopy and analysis of brown dwarf and planetary mass objects in the Orion nebula clusteren
dc.contributor.institutionSchool of Physics, Astronomy and Mathematics
dc.contributor.institutionCentre for Astrophysics Research
dc.contributor.institutionScience & Technology Research Institute
dc.description.statusPeer reviewed
dc.identifier.urlhttp://www.scopus.com/inward/record.url?scp=58049178140&partnerID=8YFLogxK
dc.relation.schoolSchool of Physics, Astronomy and Mathematics
rioxxterms.versionVoR
rioxxterms.versionofrecordhttps://doi.org/10.1111/j.1365-2966.2008.14096.x
rioxxterms.typeJournal Article/Review
herts.preservation.rarelyaccessedtrue
herts.rights.accesstypeclosedAccess


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