New, nearby bright southern ultracool dwarfs

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dc.creatorKendall, T. R.
dc.creatorJones, H. R. A.
dc.creatorPinfield, D. J.
dc.creatorPokorny, R. S.
dc.creatorFolkes, S.
dc.creatorWeights, D.
dc.creatorJenkins, J. S.
dc.creatorMauron, N.
dc.date2006-09-14
dc.date.accessioned2026-07-07T10:23:36Z
dc.date.available2026-07-07T10:23:36Z
dc.descriptionWe report the discovery of twenty-one hitherto unknown bright southern ultracool dwarfs with spectral types in the range M7 to L5.5, together with new observations of a further three late M dwarfs previously confirmed. Three more objects are already identified in the literature as high proper motion stars;we derive their spectral types for the first time. All objects were selected from the 2MASS All Sky and SuperCOSMOS point source databases on the basis of their optical/near-infrared colours, $J$-band magnitudes and proper motions. Low resolution (R $\sim$ 1000) $JH$ spectroscopy with the ESO/NTT SOFI spectrograph has confirmed the ultracool nature of 24 targets, out of a total of 25 candidates observed. Spectral types are derived by direct comparison with template objects and compared to results from H$_2$O and FeH indices. We also report the discovery of one binary, as revealed by SOFI acquisition imaging; spectra were taken for both components. The spectral types of the two components are L2 and L4 and the distance $\sim$ 19 pc. Spectroscopic distances and transverse velocities are derived for the sample. Two $\sim$ L5 objects lie only $\sim$ 10 pc distant. Such nearby objects are excellent targets for further study to derive their parallaxes and to search for fainter, later companions with AO and/or methane imaging.
dc.description11 pages, 10 figures, accepted to MNRAS
dc.identifierhttps://arxiv.org/abs/astro-ph/0609396
dc.identifierhttp://arxiv.org/abs/astro-ph/0609396
dc.identifierMon.Not.Roy.Astron.Soc.374:445-454,2007
dc.identifierdoi:10.1111/j.1365-2966.2006.11026.x
dc.identifier.urihttp://salesiana.dossiersoluciones.com/handle/123456789/175888
dc.subjectAstrophysics
dc.titleNew, nearby bright southern ultracool dwarfs
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