Template:Short description Template:Starbox begin Template:Starbox image Template:Starbox observe Template:Starbox character Template:Starbox astrometry Template:Starbox detail Template:Starbox catalog Template:Starbox reference Template:Starbox end 2M1207, 2M1207A or 2MASS J12073346–3932539 is a brown dwarf located in the constellation Centaurus; a companion object, 2M1207b, may be the first extrasolar planetary-mass companion to be directly imaged, and is the first discovered orbiting a brown dwarf.<ref name=mohanty /><ref>Template:Cite journal</ref>

2M1207 was discovered during the course of the 2MASS infrared sky survey: hence the "2M" in its name, followed by its celestial coordinates. With a fairly early (for a brown dwarf) spectral type of M8,<ref name=sb /> it is very young, and probably a member of the TW Hydrae association. Its estimated mass is around 25 Jupiter masses.<ref name=mamajek /> The companion, 2M1207b, is estimated to have a mass of 5–6 Jupiter masses.<ref name="Luhman et al 2023">Template:Cite journal</ref> Still glowing red hot, it will shrink to a size slightly smaller than Jupiter as it cools over the next few billion years.

An initial photometric estimate for the distance to 2M1207 was 70 parsecs.<ref name=mamajek /> In December 2005, American astronomer Template:Interlanguage link multi reported a more accurate distance (53 ± 6 parsecs) to 2M1207 using the moving cluster method.<ref>Template:Cite journal</ref> The new distance gives a fainter luminosity for 2M1207. Recent trigonometric parallax results have confirmed this moving cluster distance, leading to a distance estimate of 53 ± 1 parsec or 172 ± 3 light years.<ref name="mamajek">"The Distance to the 2M1207 System" Template:Webarchive, Eric Mamajek, November 8, 2007. Accessed on line June 15, 2008.</ref>

Planetary systemEdit

Like classical T Tauri stars, many brown dwarfs are surrounded by disks of gas and dust which accrete onto the brown dwarf.<ref>More Sun-like stars may have planetary systems than currently thought Template:Webarchive, library, Origins program, NASA. Accessed on line June 16, 2008.</ref><ref name=uv>First Ultraviolet Spectrum of a Brown Dwarf: Evidence for H2 Fluorescence and Accretion, John E. Gizis, Harry L. Shipman, and James A. Harvin, Astrophysical Journal 630, #1 (September 2005), pp. L89–L91. Template:Bibcode {{#invoke:doi|main}}.</ref> 2M1207 was first suspected to have such a disk because of its broad Hα line. This was later confirmed by ultraviolet spectroscopy.<ref name=uv /> The existence of a dust disk has also been confirmed by infrared observations<ref>Spitzer Observations of Two TW Hydrae Association Brown Dwarfs, Basmah Riaz, John E. Gizis, and Abraham Hmiel, Astrophysical Journal 639, #2 (March 2006), pp. L79–L82. Template:Bibcode {{#invoke:doi|main}}.</ref> and with ALMA.<ref name="Ricci et al. 2017">Template:Cite journal</ref> In general, accretion from disks are known to produce fast-moving jets, perpendicular to the disk, of ejected material.<ref>Accretion-ejection models of astrophysical jets, R. E. Pudritz, in Accretion Disks, Jets and High-energy Phenomena in Astrophysics, Vassily Beskin, Gilles Henri, Francois Menard, Guy Pelletier, and Jean Dalibard, eds., NATO Advanced Study Institute, Les Houches, session LXXVIII, EDP Sciences/Springer, 2003. Template:ISBN.</ref> This has also been observed for 2M1207; an April 2007 paper in the Astrophysical Journal reports that this brown dwarf is spouting jets of material from its poles.<ref name="Whelan et al 2007">Template:Cite journal</ref> The jets, which extend around 109 kilometers into space, were discovered using the Very Large Telescope (VLT) at the European Southern Observatory. Material in the jets streams into space at a few kilometers per second.<ref name=sp>Small Stars Create Big Fuss, Ker Than, May 28, 2007, space.com. Accessed on line June 15, 2008.</ref>

2M1207b shows weak accretion from a disk, inferred from emission lines of hydrogen and helium in medium-resolution NIRSpec data. Surprisingly 2M1207b does not show absorption due to methane, which was predicted to be present for this object. It was suggested that very young objects have a L/T-transition starts at a later spectral type.<ref>Template:Cite journal</ref>

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See alsoEdit

ReferencesEdit

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External linksEdit

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