dc.contributor.author Burningham, Ben dc.contributor.author Marley, Mark S. dc.contributor.author Line, Michael R. dc.contributor.author Lupu, Roxana dc.contributor.author Visscher, Channon dc.contributor.author Morley, Caroline V. dc.contributor.author Saumon, Didier dc.contributor.author Freedman, Richard dc.date.accessioned 2019-02-21T10:08:00Z dc.date.available 2019-02-21T10:08:00Z dc.date.issued 2017-09-01 dc.identifier.citation Burningham , B , Marley , M S , Line , M R , Lupu , R , Visscher , C , Morley , C V , Saumon , D & Freedman , R 2017 , ' Retrieval of atmospheric properties of cloudy L dwarfs ' , Monthly Notices of the Royal Astronomical Society , vol. 470 , no. 1 , pp. 1177-1197 . https://doi.org/10.1093/mnras/stx1246 dc.identifier.issn 0035-8711 dc.identifier.other PURE: 11837065 dc.identifier.other PURE UUID: 4781f234-f342-4172-8b0d-ee0b24e6b8e5 dc.identifier.other ArXiv: http://arxiv.org/abs/1701.01257v2 dc.identifier.other Scopus: 85030790045 dc.identifier.uri http://hdl.handle.net/2299/21129 dc.description © 2017 The Authors Published by Oxford University Press on behalf of the Royal Astronomical Society. dc.description.abstract We present the first results from applying the spectral inversion technique in the cloudy L dwarf regime. Our new framework provides a flexible approach to modelling cloud opacity which can be built incrementally as the data requires, and improves upon previous retrieval experiments in the brown dwarf regime by allowing for scattering in two stream radiative transfer. Our first application of the tool to two mid-L dwarfs is able to reproduce their near-infrared spectra far more closely than grid models. Our retrieved thermal, chemical, and cloud profiles allow us to estimate $T_{\rm eff} = 1796^{+23}_{-25}$ K and $\log g = 5.21^{+0.05}_{-0.08}$ for 2MASS J05002100+0330501 and for 2MASSW J2224438-015852 we find $T_{\rm eff} = 1723^{+18}_{-19}$ K and $\log g = 5.31^{+0.04}_{-0.08}$, in close agreement with previous empirical estimates. Our best model for both objects includes an optically thick cloud deck which passes $\tau_{cloud} \geq 1$ (looking down) at a pressure of around 5 bar. The temperature at this pressure is too high for silicate species to condense, and we argue that corundum and/or iron clouds are responsible for this cloud opacity. Our retrieved profiles are cooler at depth, and warmer at altitude than the forward grid models that we compare, and we argue that some form of heating mechanism may be at work in the upper atmospheres of these L dwarfs. We also identify anomalously high CO abundance in both targets, which does not correlate with the warmth of our upper atmospheres or our choice of cloud model, and find similarly anomalous alkali abundance for one of our targets. These anomalies may reflect unrecognised shortcomings in our retrieval model, or inaccuracies in our gas phase opacities. en dc.language.iso eng dc.relation.ispartof Monthly Notices of the Royal Astronomical Society dc.rights /dk/atira/pure/core/openaccesspermission/open dc.subject astro-ph.SR dc.subject astro-ph.EP dc.title Retrieval of atmospheric properties of cloudy L dwarfs en dc.contributor.institution Centre for Astrophysics Research dc.contributor.institution School of Physics, Astronomy and Mathematics dc.description.status Peer reviewed dc.relation.school School of Physics, Astronomy and Mathematics dc.description.versiontype Final Accepted Version dcterms.dateAccepted 2017-05-18 rioxxterms.version AM rioxxterms.version AM rioxxterms.versionofrecord https://doi.org/10.1093/mnras/stx1246 rioxxterms.type Journal Article/Review herts.preservation.rarelyaccessed true herts.rights.accesstype openAccess
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