EI Cancri
EI Cancri Location of EI Cancri in the constellation Cancer | |
| Observation data Epoch J2000 Equinox J2000 | |
|---|---|
| Constellation | Cancer[1] |
| A | |
| Right ascension | 08h 58m 15.07493s[2] |
| Declination | +19° 45′ 48.2581″[2] |
| Apparent magnitude (V) | 13.93[3] |
| B | |
| Right ascension | 08h 58m 15.14813s[4] |
| Declination | +19° 45′ 48.8367″[4] |
| Apparent magnitude (V) | 13.75[3] |
| Characteristics | |
| A | |
| Spectral type | M8Ve[5] |
| B | |
| Spectral type | M7V[6] |
| Astrometry | |
| A | |
| Radial velocity (Rv) | 13 ± 5[7] km/s |
| Proper motion (μ) | RA: −767.060[2] mas/yr Dec.: −100.176[2] mas/yr |
| Parallax (π) | 194.1443±0.1228 mas[2] |
| Distance | 16.80 ± 0.01 ly (5.151 ± 0.003 pc) |
| B | |
| Proper motion (μ) | RA: −937.133[4] mas/yr Dec.: −34.559[4] mas/yr |
| Parallax (π) | 196.2619±0.1976 mas[4] |
| Distance | 16.62 ± 0.02 ly (5.095 ± 0.005 pc) |
| Orbit[8] | |
| Period (P) | >42 years |
| Semi-major axis (a) | 7.0 AU |
| Details | |
| A | |
| Mass | 0.127±0.043[9] M☉ |
| Radius | 0.136±0.020[9] R☉ |
| Luminosity (bolometric) | 0.00135±0.00040[10] L☉ |
| Temperature | 2,890±79[10] K |
| Metallicity [Fe/H] | +0.08[9] dex |
| B | |
| Mass | 0.111±0.045[9] M☉ |
| Radius | 0.119±0.021[9] R☉ |
| Luminosity (bolometric) | 0.000937±0.000028[10] L☉ |
| Temperature | 2,802±78[10] K |
| Metallicity [Fe/H] | +0.14[9] dex |
| Other designations | |
| EI Cnc, GJ 1116, WDS J08582+1945AB, G 9-38, G 47-14, G 41-11, LP 426-40, LTT 12343, PLX 2144.03, GSC 01397-01138, 2MASS J08581519+1945470 | |
| A: Gaia DR2 660597997696173440, LHS 2076, NLTT 20638[11] | |
| B: Gaia DR2 660597997697274752, LHS 2077, NLTT 20637[12] | |
| Database references | |
| SIMBAD | The system |
| A | |
| B | |
EI Cancri, also known as G 9-38 and GJ 1116, is a binary star system consisting of two M-type stars.[13] Located at a distance of 16.7 light-years, it is among the nearest star systems.[14]
This system consist of two very-low-mass stars that are orbiting each other at an estimated period of 42 years and orbital separation of 7.0 astronomical units.[8] Component A has an apparent magnitude 13.93,[3] 0.127 times the Sun's mass, 0.136 times the Sun's radius,[9] and 0.14% of the Sun's luminosity.[10] Component B has an apparent magnitude 13.75,[3] 0.111 times the Sun's mass, 0.119 times the Sun's radius,[9] and 0.09% of the Sun's luminosity.[10] At the very end of the main sequence, with spectral classifications of M8Ve[5] and M7V[6] respectively, their effective temperatures are below 3,000 K.[10] A 2015 search for a third star in the system has yielded inconclusive results.[15]
In 1985, Bjørn Ragnvald Pettersen announced his discovery that the star shows very high stellar flare activity, with an average of five flares per hour.[16] It was given its variable star designation, EI Cancri, in 1987.[17]
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 d Lépine, Sébastien; Shara, Michael M. (2005-03-01). "A Catalog of Northern Stars with Annual Proper Motions Larger than 015 (LSPM-NORTH Catalog)". The Astronomical Journal. 129 (3): 1483. arXiv:astro-ph/0412070. Bibcode:2005AJ....129.1483L. doi:10.1086/427854. ISSN 1538-3881.
- ^ 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 Cowley, A. P.; Hartwick, F. D. A. (1982). "Studies of late-type dwarfs. III. Radial velocities and spectral characteristics for 74 stars". The Astrophysical Journal. 253: 237–241. Bibcode:1982ApJ...253..237C. doi:10.1086/159628. ISSN 0004-637X.
- ^ a b Newton, Elisabeth R.; Charbonneau, David; Irwin, Jonathan; Berta-Thompson, Zachory K.; Rojas-Ayala, Barbara; Covey, Kevin; Lloyd, James P. (2013-12-12). "Near-infrared Metallicities, Radial Velocities and Spectral Types for 447 Nearby M Dwarfs". The Astronomical Journal. 147 (1): 20. arXiv:1310.1087. Bibcode:2014AJ....147...20N. doi:10.1088/0004-6256/147/1/20. ISSN 0004-6256.
- ^ "G9-38". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 29 September 2020.
- ^ a b Li, Hua-Li; Wang, Jing; et al. (September 2023). "White-light Superflare and Long-term Activity of the Nearby M7-type Binary EI Cnc Observed with GWAC System". The Astrophysical Journal. 954 (2): 142. arXiv:2307.14594. Bibcode:2023ApJ...954..142L. doi:10.3847/1538-4357/ace59b.
- ^ a b c d e f g h Cifuentes, C.; Caballero, J. A.; González-Payo, J.; Amado, P. J.; Béjar, V. J. S.; Burgasser, A. J.; Cortés-Contreras, M.; Lodieu, N.; Montes, D.; Quirrenbach, A.; Reiners, A.; Ribas, I.; Sanz-Forcada, J.; Seifert, W.; Zapatero Osorio, M. R. (January 2025). "CARMENES input catalogue of M dwarfs. IX. Multiplicity from close spectroscopic binaries to ultra-wide systems". Astronomy and Astrophysics. 693: A228. Bibcode:2025A&A...693A.228C. doi:10.1051/0004-6361/202452527. ISSN 0004-6361.
- ^ a b c d e f g Hardegree-Ullman, Kevin K.; Apai, Dániel; Bergsten, Galen J.; Pascucci, Ilaria; López-Morales, Mercedes (2023). "Bioverse: A Comprehensive Assessment of the Capabilities of Extremely Large Telescopes to Probe Earth-like O2 Levels in Nearby Transiting Habitable-zone Exoplanets". The Astronomical Journal. 165 (6): 267. arXiv:2304.12490. Bibcode:2023AJ....165..267H. doi:10.3847/1538-3881/acd1ec.
- ^ "G9-38A". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 29 September 2020.
- ^ "G9-38B". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 29 September 2020.
- ^ Vizier query: Name=G* 1116, Centre de Données astronomiques de Strasbourg, accessed 30 December 2012.
- ^ Nearby Stars Catalog (NSC) Archived 2021-02-27 at the Wayback Machine, Planetary Habitability Laboratory, University of Puerto Rico at Arecibo accessed 31 December 2012.
- ^ Davison, Cassy L.; White, R. J.; Henry, T. J.; Riedel, A. R.; Jao, W-C.; Bailey Iii, J. I.; Quinn, S. N.; Cantrell, J. R.; Subasavage, J. P.; Winters, J. G. (2015). "A 3D Search for Companions to 12 Nearby M-Dwarfs". The Astronomical Journal. 149 (3): 106. arXiv:1501.05012. Bibcode:2015AJ....149..106D. doi:10.1088/0004-6256/149/3/106. S2CID 9719725.
- ^ a b Pettersen, B. R. (July 1985). "Discovery of flare activity on the low luminosity red dwarf system G9-38 AB". Astronomy & Astrophysics. 148: 151–154. Bibcode:1985A&A...148..151P. Retrieved 11 November 2021.
- ^ Kholopov, P. N.; Samus, N. N.; Kazarovets, E. V.; Kireeva, N. N. (August 1987). "The 68th Name-List of Variable Stars" (PDF). Information Bulletin on Variable Stars. 3058: 1–30. Bibcode:1987IBVS.3058....1K. Retrieved 1 January 2025.
Further reading
- Dittmann, Jason A.; Irwin, Jonathan M.; Charbonneau, David; Berta-Thompson, Zachory K. (2014). "Trigonometric Parallaxes for 1507 Nearby Mid-to-late M Dwarfs". The Astrophysical Journal. 784 (2): 156. arXiv:1312.3241. Bibcode:2014ApJ...784..156D. doi:10.1088/0004-637X/784/2/156. S2CID 18789867. Table with parallaxes.