G 9-38

Last updated
GJ 1116
EICncLightCurve.png
An ultraviolet band light curve showing several flares on EI Cancri, adapted from Pettersen (1985) [1]
Observation data
Epoch J2000       Equinox J2000
Constellation Cancer
Right ascension 08h 58m 15.194s [2]
Declination +19° 45′ 47.08″ [2]
Apparent magnitude  (V)13.720 [3]
Characteristics
Spectral type M8Ve+M7V [4] [5]
Astrometry
G 9-38 A
Radial velocity (Rv)13 ± 5 [6] km/s
Proper motion (μ)RA: −767.060±0.122 [7] mas/yr
Dec.: −100.176±0.083 [7] mas/yr
Parallax (π)194.1443±0.1228  mas [7]
Distance 16.80 ± 0.01  ly
(5.151 ± 0.003  pc)
G 9-38 B
Proper motion (μ)RA: −937.133±0.190 [8] mas/yr
Dec.: −34.559±0.138 [8] mas/yr
Parallax (π)196.2619 ± 0.1976  mas [8]
Distance 16.62 ± 0.02  ly
(5.095 ± 0.005  pc)
Orbit
PrimaryG 9-38A
CompanionG 9-38B
Period (P)360 yr
Semi-major axis (a)33 AU
Details [9] [10]
G 9-38A
Mass 0.127±0.043 [11]   M☉
Radius 0.136±0.020 [11]   R☉
Luminosity (bolometric)0.000965  L☉
Temperature 2896±18  K
Metallicity [Fe/H]+0.08 [11]   dex
G 9-38B
Mass 0.111±0.045 [11]   M☉
Radius 0.119±0.021 [11]   R☉
Luminosity (bolometric)0.000992  L☉
Metallicity [Fe/H]+0.14 [11]   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 [4] , NLTT 20638 [4]
B: Gaia DR2 660597997697274752, LHS 2077 [5] , NLTT 20637 [5]
Database references
SIMBAD The system
A
B
Cancer constellation map.svg
Red pog.png
G 9-38
Location of G 9-38 in the constellation Cancer

G 9-38, also known as EI Cancri and GJ 1116, is a binary star system consisting of two M-type stars. [12] Located at a distance of 16.7 light-years, it is among the nearest star systems. [13]

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. [1] It was given its variable star designation, EI Cancri, in 1987. [14]

In 2015, the search for third star in the system has yielded inconclusive results. [15]

References

  1. 1 2 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.
  2. 1 2 Cutri, Roc M.; Skrutskie, Michael F.; Van Dyk, Schuyler D.; Beichman, Charles A.; Carpenter, John M.; Chester, Thomas; Cambresy, Laurent; Evans, Tracey E.; Fowler, John W.; Gizis, John E.; Howard, Elizabeth V.; Huchra, John P.; Jarrett, Thomas H.; Kopan, Eugene L.; Kirkpatrick, J. Davy; Light, Robert M.; Marsh, Kenneth A.; McCallon, Howard L.; Schneider, Stephen E.; Stiening, Rae; Sykes, Matthew J.; Weinberg, Martin D.; Wheaton, William A.; Wheelock, Sherry L.; Zacarias, N. (2003). "VizieR Online Data Catalog: 2MASS All-Sky Catalog of Point Sources (Cutri+ 2003)". CDS/ADC Collection of Electronic Catalogues. 2246: II/246. Bibcode:2003yCat.2246....0C.
  3. ↑ Zacharias, N. (2012). "The fourth US Naval Observatory CCD Astrograph Catalog (UCAC4)". VizieR On-line Data Catalog. Bibcode:2012yCat.1322....0Z.
  4. 1 2 3 "G9-38A". SIMBAD . Centre de données astronomiques de Strasbourg . Retrieved 29 September 2020.
  5. 1 2 3 "G9-38B". SIMBAD . Centre de données astronomiques de Strasbourg . Retrieved 29 September 2020.
  6. ↑ "G9-38". SIMBAD . Centre de données astronomiques de Strasbourg . Retrieved 29 September 2020.
  7. 1 2 3 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.
  8. 1 2 3 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.
  9. ↑ Rojas-Ayala, Bárbara; Covey, Kevin R.; Muirhead, Philip S.; Lloyd, James P. (2011), "Metallicity and Temperature Indicators in M dwarf K band Spectra: Testing New & Updated Calibrations With Observations of 133 Solar Neighborhood M dwarfs", The Astrophysical Journal, 748 (2): 93, arXiv: 1112.4567 , Bibcode:2012ApJ...748...93R, doi:10.1088/0004-637X/748/2/93, S2CID   41902340
  10. ↑ Nearby Star Summary Table
  11. 1 2 3 4 5 6 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.
  12. ↑ Vizier query: Name=G* 1116, Centre de Données astronomiques de Strasbourg, accessed 30 December 2012.
  13. ↑ 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.
  14. ↑ 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.
  15. ↑ 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


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