2MASS J18352154−3123385, often shortened to be 2MASS J1835, is a binary red dwarf system about 27 light-years from the Earth. It was first reported due to its high proper motion in 2010 by J. D. Kirkpatrick et al.[6][7] It was then independently discovered from its X-ray radiation on June 10, 2015. Further investigation has shown the star to be a binary star with components of spectral type M6.5 and M8. They orbit each other in 1,400-1,800 years, and reached their closest point in mid-1968 assuming a constant proper motion. During their closest approach, they were separated by less than 0.1 arcsecond, compared to their current separation of 2 arcseconds.
| Observation data Epoch J2000.0 Equinox J2000.0 | |
|---|---|
| Constellation | Sagittarius |
| 2MASS J18352154-3123385[1] | |
| Right ascension | 18h 35m 21.543s |
| Declination | –31° 23′ 38.53″ |
| Apparent magnitude (V) | 12.5 |
| 2MASS J18352205-3123421[2] | |
| Right ascension | 18h 35m 22.050s |
| Declination | –31° 23′ 42.19″ |
| Apparent magnitude (V) | 13.0 |
| Characteristics | |
| 2MASS J18352154-3123385 | |
| Spectral type | M6.5V |
| Apparent magnitude (J) | 8.652 |
| Apparent magnitude (H) | 8.097 |
| Apparent magnitude (K) | 7.803 |
| Characteristics | |
| 2MASS J18352205−3123421 | |
| Spectral type | M8V |
| Apparent magnitude (J) | 9.438 |
| Apparent magnitude (H) | 8.815 |
| Apparent magnitude (K) | 8.533 |
| Astrometry | |
| 2MASS J18352154−3123385 | |
| Proper motion (μ) | RA: 21±4 mas/yr[3] Dec.: −382±4 mas/yr[3] |
| Parallax (π) | 58.16 ± 0.04 mas |
| Distance | 56.08 ± 0.04 ly (17.19 ± 0.01 pc) |
| 2MASS J18352205−3123421 | |
| Proper motion (μ) | RA: 28.53±0.04 mas/yr[4] Dec.: -380.00±0.04 mas/yr[4] |
| Parallax (π) | 58.0782 ± 0.0480 mas[4] |
| Distance | 56.16 ± 0.05 ly (17.22 ± 0.01 pc) |
| Orbit | |
| Primary | 2MASS J18352154-3123385 |
| Companion | 2MASS J18352205−3123421 |
| Period (P) | ~1400–1800? yr |
| Semi-major axis (a) | 5070 AU |
| Inclination (i) | ~55° |
| Longitude of the node (Ω) | ~5° |
| Periastron epoch (T) | ~1968[1] |
| Details[5] | |
| 2MASS J18352154-3123385 | |
| Mass | 0.29 M☉ |
| Radius | 0.3 R☉ |
| Luminosity | 0.0012 L☉ |
| Temperature | 3376 K |
| Metallicity [Fe/H] | -0.07 dex |
| 2MASS J18352205−3123421 | |
| Other designations | |
1RXS J183520.9−312327, PM J18353-3123W, LP 923-18 | |
| Database references | |
| SIMBAD | data |
Despite the fact that A and B are magnitude 12.5 and 13, respectively, their vicinity to the Earth was not noticed until 2015 due to the fact that it is in front of a relatively dense star field less than 15 degrees away from the Galactic Center.[citation needed]
2MASS J1835A may be a flare star, due to many similar low-mass stars known to flare. It has not been observed to flare directly by 2015, however.
A 19th-magnitude star at 18h 35m 22.76s −31° 23′ 27.7″ has been seen in the vicinity, with a similar proper motion to 2MASS J1835, but is probably not related as its proper motion is not as high as 2MASS J1835. Due to its dimness, insufficient data exists to determine its spectral type.
See also
editNotes
edit^ given date is not the date of periastron, but rather the date of the closest separation between 2MASS J1835A and B.
References
edit- ^ "2MASS J18352154-3123385". SIMBAD. Retrieved 21 December 2015.
- ^ "2MASS J18352205-3123421". SIMBAD. Retrieved 21 December 2015.
- ^ URAT South Parallax Results Table 5. New Nearby Star Discoveries URAT South Epoch Data
- ^ a b Brown, A. G. A.; et al. (Gaia collaboration) (2021). "Gaia Early Data Release 3: Summary of the contents and survey properties". Astronomy & Astrophysics. 649: A1. arXiv:2012.01533. Bibcode:2021A&A...649A...1G. doi:10.1051/0004-6361/202039657. S2CID 227254300. (Erratum: doi:10.1051/0004-6361/202039657e). Gaia EDR3 record for this source at VizieR.
- ^ Trumpeting M dwarfs with CONCH-SHELL: a catalogue of nearby cool host-stars for habitable exoplanets and life supplementary data
- ^ Kirkpatrick, J. Davy (2010). "Discoveries from a Near-Infrared Proper Motion Survey using Multi-Epoch Two Micron All-Sky Survey Data". The Astrophysical Journal Supplement Series. 190 (1). Institution of Physics: 100–146. arXiv:1008.3591. Bibcode:2010ApJS..190..100K. doi:10.1088/0067-0049/190/1/100. S2CID 118435904.
- ^ Kirkpatrick, J. D. "Discoveries from a Near-infrared Proper Motion Survey using Multi-epoch 2MASS Data (full text table)". IOPscience. Institute of Physics. Retrieved 21 December 2015.