2M1207 was discovered during the course of the 2MASSinfrared 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,[1] it is very young, and probably a member of the TW Hydrae association. Its estimated mass is around 25 Jupiter masses.[4] The companion, 2M1207b, is estimated to have a mass of 5–6 Jupiter masses.[7] 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.[4] In December 2005, American astronomer Eric Mamajek [fr] reported a more accurate distance (53 ± 6 parsecs) to 2M1207 using the moving cluster method.[8] 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.[4]
Planetary system
Like classical T Tauri stars, many brown dwarfs are surrounded by disks of gas and dust which accrete onto the brown dwarf.[9][10] 2M1207 was first suspected to have such a disk because of its broad Hα line. This was later confirmed by ultravioletspectroscopy.[10] The existence of a dust disk has also been confirmed by infrared observations[11] and with ALMA.[12] In general, accretion from disks are known to produce fast-moving jets, perpendicular to the disk, of ejected material.[13] 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.[14] 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.[15]
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.[16]
^ abcAn accurate distance to 2M1207Ab, C. Ducourant, R. Teixeira, G. Chauvin, G. Daigne, J.-F. Le Campion, Inseok Song, and B. Zuckerman, Astronomy and Astrophysics477, #1 (January 2008), pp. L1–L4. Bibcode:2008A&A...477L...1Ddoi:10.1051/0004-6361:20078886.
^ abcdeThe Planetary Mass Companion 2MASS 1207-3932B: Temperature, Mass, and Evidence for an Edge-on Disk, Subhanjoy Mohanty, Ray Jayawardhana, Nuria Huelamo, and Eric Mamajek, Astrophysical Journal657, #2 (March 2007), pp. 1064–1091. Bibcode:2007ApJ...657.1064Mdoi:10.1086/510877.
^ abFirst Ultraviolet Spectrum of a Brown Dwarf: Evidence for H2 Fluorescence and Accretion, John E. Gizis, Harry L. Shipman, and James A. Harvin, Astrophysical Journal630, #1 (September 2005), pp. L89–L91. Bibcode:2005ApJ...630L..89Gdoi:10.1086/462414.
^Spitzer Observations of Two TW Hydrae Association Brown Dwarfs, Basmah Riaz, John E. Gizis, and Abraham Hmiel, Astrophysical Journal639, #2 (March 2006), pp. L79–L82. Bibcode:2006ApJ...639L..79Rdoi:10.1086/502647.
^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. ISBN3-540-20171-8.
^Whelan; Ray, T. P.; Randich, S.; Bacciotti, F.; Jayawardhana, R.; Testi, L.; Natta, A.; Mohanty, S.; et al. (April 10, 2007). "Discovery of a Bipolar Outflow from 2MASSW J1207334-393254, a 24 MJup Brown Dwarf". The Astrophysical Journal. 659 (1): L45 –L48. arXiv:astro-ph/0703112. Bibcode:2007ApJ...659L..45W. doi:10.1086/516734. S2CID14575014.
^From Gaia distance of 64.7 ± 0.5 parsec and observed angular separation of 769 ± 10 milliarseconds (angular separation from Mohanty 2007, above.) Real semimajor axis might be higher due to viewing angle and eccentricity of the orbit.
