Astronomy:GJ 3991

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Short description: Star in the constellation Hercules
GJ 3991
Observation data
Equinox J2000.0]] (ICRS)
Constellation Hercules[1]
Right ascension  17h 09m 31.544s[2]
Declination +43° 40′ 52.77″[2]
Apparent magnitude (V) 13.671[3]
Characteristics
Spectral type M3.5V[4]
Apparent magnitude (B) 13.46
Apparent magnitude (R) 11.511
Apparent magnitude (J) 7.380
Apparent magnitude (H) 6.76
Apparent magnitude (K) 6.485
Astrometry
Radial velocity (Rv)−27.87[5] km/s
Proper motion (μ) RA: +332.032[2] mas/yr
Dec.: −274.501[2] mas/yr
Parallax (π)131.5996 ± 0.4285[2] mas
Distance24.78 ± 0.08 ly
(7.60 ± 0.02 pc)
Absolute magnitude (MV)12.41[6]
Orbit[7]
Period (P)14.7136±0.0005 days
(0.0402836±0.0000014 yr)
Semi-major axis (a)0.015+0.01
−0.05"
(0.1102 AU)
Eccentricity (e)0.068±0.004
Argument of periapsis (ω)
(primary)		175.0±3.0°
Semi-amplitude (K1)
(primary)		50.6±0.2 km/s
Details
GJ 3991 A
Mass0.20[citation needed] M☉
Temperature3250±50[citation needed] K
Metallicity [Fe/H]0.20±0.06[citation needed] dex
GJ 3991 B
Mass0.50[citation needed] M☉
Temperature~4900[citation needed] K
Age>6?[citation needed] Gyr
Other designations
GJ 3991, HIP 83945, G 203-47, WD 1708+437, USNO 752[8]
Database references
SIMBADdata

GJ 3991 (also known as Gliese 3991 and G 203-47) is a binary star system located 24.2 light-years away in the constellation Hercules. It consists of a red dwarf star with 20–30% the mass of the Sun, and a white dwarf star roughly 50% the mass of the sun. The two components orbit each other in a tight orbit only 0.11 astronomical units from each other, with an orbital period of only 14.71 days. Due to their small separation, the two objects have never been visually resolved and are merely predicted from the radial velocity changes of GJ 3991, making the system a spectroscopic binary.

White dwarf

GJ 3991 B was first identified in 1997 by astronomers I. N. Reid and J. E. Gizis through significant radial velocity variations, although were unable to identify the nature of the secondary object.[9] In 1998, another group of astronomers was able to determine the secondary as a cold white dwarf star, the compact remnant that remains after a low-mass star such as the Sun is no longer able to fuse elements for energy. GJ 3991 B is the 9th nearest white dwarf, after Sirius B, Procyon B, Van Maanen 2, LP 145-141, 40 Eridani B, Stein 2051 B, G 240-72, and Gliese 223.2.[10]

Some sources call the component stars A & B,[9][10] while others call them Aa & Ab.[7]

See also

References

  1. ↑ Roman, Nancy G. (1987). "Identification of a constellation from a position". Publications of the Astronomical Society of the Pacific 99 (617): 695. doi:10.1086/132034. Bibcode: 1987PASP...99..695R  Constellation record for this object at VizieR.
  2. ↑ 2.0 2.1 2.2 2.3 2.4 Vallenari, A. et al. (2022). "Gaia Data Release 3. Summary of the content and survey properties". Astronomy & Astrophysics. doi:10.1051/0004-6361/202243940  Gaia DR3 record for this source at VizieR.
  3. ↑ Høg, E.; Fabricius, C.; Makarov, V. V.; Urban, S.; Corbin, T.; Wycoff, G.; Bastian, U.; Schwekendiek, P. et al. (2000). "The Tycho-2 catalogue of the 2.5 million brightest stars". Astronomy and Astrophysics 355. Bibcode: 2000A&A...355L..27H. 
  4. ↑ Henry, Todd J.; Walkowicz, Lucianne M.; Barto, Todd C.; Golimowski, David A. (2002). "The Solar Neighborhood. VI. New Southern Nearby Stars Identified by Optical Spectroscopy". The Astronomical Journal 123 (4): 2002. doi:10.1086/339315. Bibcode: 2002AJ....123.2002H. 
  5. ↑ Fouqué, Pascal; Moutou, Claire; Malo, Lison; Martioli, Eder; Lim, Olivia; Rajpurohit, Arvind; Artigau, Etienne; Delfosse, Xavier et al. (2018). "SPIRou Input Catalogue: Global properties of 440 M dwarfs observed with ESPaDOnS at CFHT". Monthly Notices of the Royal Astronomical Society 475 (2): 1960. doi:10.1093/mnras/stx3246. Bibcode: 2018MNRAS.475.1960F. 
  6. ↑ Anderson, E.; Francis, Ch. (2012). "XHIP: An extended hipparcos compilation". Astronomy Letters 38 (5): 331. doi:10.1134/S1063773712050015. Bibcode: 2012AstL...38..331A  XHIP record for this object at VizieR.
  7. ↑ 7.0 7.1 Delfosse, Xavier et al. (April 1999), "New neighbours. I. 13 new companions to nearby M dwarfs", Astronomy and Astrophysics 344: 897–910, Bibcode: 1999A&A...344..897D. 
  8. ↑ "G 203-47". SIMBAD. Centre de données astronomiques de Strasbourg. http://simbad.u-strasbg.fr/simbad/sim-basic?Ident=G+203-47. 
  9. ↑ 9.0 9.1 Reid, I. Neill; Gizis, John E. (June 1997). "Low-Mass Binaries and the Stellar Luminosity Function" (in en). The Astronomical Journal 113: 2246. doi:10.1086/118436. ISSN 0004-6256. Bibcode: 1997AJ....113.2246R. 
  10. ↑ 10.0 10.1 Reylé, Céline; Jardine, Kevin; Fouqué, Pascal; Caballero, Jose A.; Smart, Richard L.; Sozzetti, Alessandro (30 April 2021), "The 10 parsec sample in the Gaia era", Astronomy & Astrophysics 650: A201, doi:10.1051/0004-6361/202140985, Bibcode: 2021A&A...650A.201R  Data available at https://gruze.org/10pc/



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