 European Southern Observatory infrared image of 2M1207 (bluish) and companion planet 2M1207b (reddish), taken in 2004. | |
| Observation data Epoch J2000.0 Equinox J2000.0 (ICRS) | |
|---|---|
| Constellation | Centaurus[1] |
| Right ascension | 12h 07m 33.47s[2] |
| Declination | −39° 32′ 54.0″[2] |
| Apparent magnitude (V) | 20.15[3] |
| Characteristics | |
| Evolutionary stage | brown dwarf[4] |
| Spectral type | M8IVe[4] |
| V−R color index | +2.1[3] |
| R−I color index | +2.1[3] |
| Astrometry | |
| Proper motion (μ) | RA: −64.040±0.087[2] mas/yr Dec.: −23.678±0.072[2] mas/yr |
| Parallax (π) | 15.4624±0.1163 mas[2] |
| Distance | 211 ± 2 ly (64.7 ± 0.5 pc) |
| Details | |
| Mass | ~0.025[5] M☉ |
| Radius | 2.6[6] RJup |
| Luminosity | 0.0038[6] L☉ |
| Surface gravity (log g) | 4.3[6] cgs |
| Temperature | 2,780[6] K |
| Age | 5-10[7] Myr |
| Other designations | |
| 2MASSW J1207334−393254, 2MASS J12073346−3932539, TWA 27[4] | |
| Database references | |
| SIMBAD | data |
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.[7][8]
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,[4] it is very young, and probably a member of the TW Hydrae association. Its estimated mass is around 25 Jupiter masses.[5] The companion, 2M1207b, is estimated to have a mass of 5–6 Jupiter masses.[9] 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.[5] In December 2005, American astronomer Eric Mamajek reported a more accurate distance (53 ± 6 parsecs) to 2M1207 using the moving cluster method.[10] 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.[5]
Planetary system
Like classical T Tauri stars, many brown dwarfs are surrounded by disks of gas and dust which accrete onto the brown dwarf.[11][12] 2M1207 was first suspected to have such a disk because of its broad Hα line. This was later confirmed by ultraviolet spectroscopy.[12] The existence of a dust disk has also been confirmed by infrared observations[13] and with ALMA.[14] In general, accretion from disks are known to produce fast-moving jets, perpendicular to the disk, of ejected material.[15] 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.[16] 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.[17] While previous observations with the Spitzer spectrograph already detected acetylene (C2H2) emission in the disk of 2M1207, new observations with MIRI revealed emission of a wide variety of chemicals in the disk, showing a carbon-rich chemistry. In this study 2M1207 and ISO-ChaI 147 showed the largest number of organic molecules, including the only detection of ethylene (C2H4) in this sample. The detected chemicals include 9 hydrocarbons, with diacetylene (C4H2) and benzene (C6H6) being two prominent emission lines in the spectrum of 2M1207. Other emissions by chemicals in the disk are hydrogen gas (H2), hydrogen cyanide (HCN) and carbon dioxide (CO2).[18]
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.[19]
| Companion (in order from star) |
Mass | Semimajor axis (AU) |
Orbital period (years) |
Eccentricity | Inclination | Radius |
|---|---|---|---|---|---|---|
| circumstellar disk | 9.4±1.5 AU | 35+20 −15° |
— | |||
| b | 5.5±0.5[9] MJ | ≥ 49.8 ± 1.1[a] | 633–20046 | 0.02–0.98 | 13–150° | 1.2[6] – 1.40 ±0.01[21] RJ |
See also
Notes
- ^ 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.
References
- ^ Roman, Nancy G. (1987). "Identification of a constellation from a position". Publications of the Astronomical Society of the Pacific. 99 (617): 695. Bibcode:1987PASP...99..695R. doi:10.1086/132034. Constellation record for this object at VizieR.
- ^ a b c d e Vallenari, A.; et al. (Gaia collaboration) (2023). "Gaia Data Release 3. Summary of the content and survey properties". Astronomy and Astrophysics. 674: A1. arXiv:2208.00211. Bibcode:2023A&A...674A...1G. doi:10.1051/0004-6361/202243940. S2CID 244398875. Gaia DR3 record for this source at VizieR.
- ^ a b c Ducourant, C.; Teixeira, R.; Chauvin, G.; Daigne, G.; Le Campion, J.-F.; Song, I.; Zuckerman, B. (2008). "An accurate distance to 2M1207Ab". Astronomy & Astrophysics. 477 (1): L1–L4. arXiv:0711.0842. Bibcode:2008A&A...477L...1D. doi:10.1051/0004-6361:20078886.
- ^ a b c d "TWA 27". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved June 15, 2008.
- ^ a b c d "The Distance to the 2M1207 System" Archived 2008-01-24 at the Wayback Machine, Eric Mamajek, November 8, 2007. Accessed on line June 15, 2008.
- ^ a b c d e Patapis, P.; Morales-Calderón, M.; Arabhavi, A. M.; Kühnle, H.; Gasman, D.; Cugno, G.; Mollière, P.; Matthews, E.; Mâlin, M.; Whiteford, N.; Lagage, P.-O.; Waters, R.; Guedel, M.; Henning, Th.; Vandenbussche, B. (December 2025). "JWST/MIRI observations of the young TWA 27 system: Hydrocarbon disk chemistry, silicate clouds, and evidence of a circumplanetary disk". Astronomy & Astrophysics. 704: A5. doi:10.1051/0004-6361/202556296. hdl:2066/326486. ISSN 0004-6361.
- ^ a b Mohanty, Subhanjoy; Jayawardhana, Ray; Huelamo, Nuria; Mamajek, Eric (2007). "The Planetary Mass Companion 2MASS 1207−3932B: Temperature, Mass, and Evidence for an Edge-on Disk". The Astrophysical Journal. 657 (2): 1064–1091. arXiv:astro-ph/0610550. Bibcode:2007ApJ...657.1064M. doi:10.1086/510877.
- ^ Chauvin, G.; Lagrange, A.-M.; Dumas, C.; Zuckerman, B.; Mouillet, D.; Song, I.; Beuzit, J.-L.; Lowrance, P. (2004). "A Giant Planet Candidate near a Young Brown Dwarf". Astron. Astrophys. 425 (2): L29–L32. arXiv:astro-ph/0409323. Bibcode:2004A&A...425L..29C. doi:10.1051/0004-6361:200400056. S2CID 15948759.
- ^ a b c Luhman, K. L.; Tremblin, P.; Birkmann, S. M.; Manjavacas, E.; Valenti, J.; Alves de Oliveira, C.; Beck, T. L.; Giardino, G.; Lützgendorf, N.; Rauscher, B. J.; Sirianni, M. (2023-06-01). "JWST/NIRSpec Observations of the Planetary Mass Companion TWA 27B". The Astrophysical Journal. 949 (2): L36. arXiv:2305.18603. Bibcode:2023ApJ...949L..36L. doi:10.3847/2041-8213/acd635. ISSN 0004-637X.
- ^ Mamajek (2005). "A Moving Cluster Distance to the Exoplanet 2M1207b in the TW Hydrae Association". The Astrophysical Journal. 634 (2): 1385–1394. arXiv:astro-ph/0507416. Bibcode:2005ApJ...634.1385M. doi:10.1086/468181. S2CID 17162407.
- ^ More Sun-like stars may have planetary systems than currently thought Archived 2008-09-17 at the Wayback Machine, library, Origins program, NASA. Accessed on line June 16, 2008.
- ^ a b Gizis, John E.; Shipman, Harry L.; Harvin, James A. (2005). "First Ultraviolet Spectrum of a Brown Dwarf: Evidence for H 2 Fluorescence and Accretion". The Astrophysical Journal. 630 (1): L89–L91. arXiv:astro-ph/0507429. Bibcode:2005ApJ...630L..89G. doi:10.1086/462414.
- ^ Riaz, Basmah; Gizis, John E.; Hmiel, Abraham (2006). "Spitzer Observations of Two TW Hydrae Association Brown Dwarfs". The Astrophysical Journal. 639 (2): L79–L82. arXiv:astro-ph/0606666. Bibcode:2006ApJ...639L..79R. doi:10.1086/502647.
- ^ a b Ricci, L.; Cazzoletti, P.; Czekala, I.; Andrews, S. M.; Wilner, D.; Szűcs, L.; Lodato, G.; Testi, L.; Pascucci, I.; Mohanty, S.; Apai, D.; Carpenter, J. M.; Bowler, B. P. (2017-07-01). "ALMA Observations of the Young Substellar Binary System 2M1207". The Astronomical Journal. 154 (1): 24. arXiv:1706.03708. Bibcode:2017AJ....154...24R. doi:10.3847/1538-3881/aa78a0. hdl:10150/624920. ISSN 0004-6256.
- ^ 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. ISBN 3-540-20171-8.
- ^ 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. S2CID 14575014.
- ^ Small Stars Create Big Fuss, Ker Than, May 28, 2007, space.com. Accessed on line June 15, 2008.
- ^ Arabhavi, A. M.; Kamp, I.; Henning, Th.; van Dishoeck, E. F.; Jang, H.; Waters, L. B. F. M.; Christiaens, V.; Gasman, D.; Pascucci, I.; Perotti, G.; Grant, S. L.; Güdel, M.; Lagage, P. -O.; Barrado, D.; Caratti o Garatti, A.; Lahuis, F.; Kaeufer, T.; Kanwar, J.; Morales-Calderón, M.; Schwarz, K.; Sellek, A. D.; Tabone, B.; Temmink, M.; Vlasblom, M.; Patapis, P. (2025). "MINDS: The very low-mass star and brown dwarf sample. Detections and trends in the inner disk gas". Astronomy & Astrophysics. 699: A194. arXiv:2506.02748. Bibcode:2025A&A...699A.194A. doi:10.1051/0004-6361/202554109.
- ^ Elena, Manjavacas; Tremblin, Pascal; Birkmann, Stephan; Valenti, Jeff; Alves de Oliveira, Catarina; Beck, Tracy L.; Giardino, G.; Luetzgendorf, N.; Rauscher, B. J.; Sirianni, M. (February 2024). "Medium Resolution 0.97-5.3 micron spectra of Very Young Benchmark Brown Dwarfs with NIRSpec onboard the James Webb Space Telescope". AJ. arXiv:2402.04230.
- ^ Blunt, Sarah; Nielsen, Eric L.; De Rosa, Robert J.; Konopacky, Quinn M.; Ryan, Dominic; Wang, Jason J.; Pueyo, Laurent; Rameau, Julien; Marois, Christian; Marchis, Franck; Macintosh, Bruce; Graham, James R.; Duchêne, Gaspard; Schneider, Adam C. (2017-05-01). "Orbits for the Impatient: A Bayesian Rejection-sampling Method for Quickly Fitting the Orbits of Long-period Exoplanets". The Astronomical Journal. 153 (5): 229. arXiv:1703.10653. Bibcode:2017AJ....153..229B. doi:10.3847/1538-3881/aa6930. ISSN 0004-6256.
- ^ Zhang, Zhoujian; Mollière, Paul; Fortney, Jonathan J.; Marley, Mark S. (August 2025). "Elemental Abundances of Planets and Brown Dwarfs Imaged around Stars (ELPIS). II. The Jupiter-like Inhomogeneous Atmosphere of the First Directly Imaged Planetary-mass Companion 2MASS 1207 b". The Astronomical Journal. 170 (2): 64. arXiv:2502.18559. Bibcode:2025AJ....170...64Z. doi:10.3847/1538-3881/addfcb. Retrieved 27 October 2025.
External links
- Space.com - Astronomers Confident: Planet Beyond Solar System Has Been Photographed
- Space.com article on the discovery
- Jean Schneider (2011). "Notes for star 2M1207". Extrasolar Planets Encyclopaedia. Archived from the original on 6 October 2011. Retrieved 3 October 2011.
- "A Giant Planet Candidate Near a Young Brown Dwarf" (PDF) from the European Southern Observatory.
- Mamajek, Eric E. (2005). "A Moving Cluster Distance to the Exoplanet 2M1207b in the TW Hydrae Association". The Astrophysical Journal. 634 (2): 1385. arXiv:astro-ph/0507416. Bibcode:2005ApJ...634.1385M. doi:10.1086/468181.
