Astronomy: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[5] |
| Apparent magnitude (R) | 11.511[5] |
| Apparent magnitude (J) | 7.380[5] |
| Apparent magnitude (H) | 6.76[5] |
| Apparent magnitude (K) | 6.485[5] |
| Astrometry | |
| Radial velocity (Rv) | −27.87[6] 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 |
| Distance | 24.78 ± 0.08 ly (7.60 ± 0.02 pc) |
| Absolute magnitude (MV) | 12.41[7] |
| Orbit[8] | |
| Period (P) | 14.909777±0.00001 days[9] |
| 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 | |
| Mass | 0.2714+0.0066 −0.0065[10] M☉ |
| Radius | 0.286±0.011[10] R☉ |
| Luminosity | 0.0085±0.0001[11] L☉ |
| Temperature | 3279+65 −63[10] K |
| GJ 3991 B | |
| Mass | ≳0.5[11] M☉ |
| Surface gravity (log g) | 8.0+1.00 −0.13[11] cgs |
| Temperature | 5286+788 −91[11] K |
| Rotation | >100 days[11] |
| Age | (as white dwarf) ~4[11] Gyr |
| Other designations | |
| Database references | |
| SIMBAD | data |
| ARICNS | data |
GJ 3991 (also known as Gliese 3991 and G 203-47) is a binary star system located 24.78 light-years (7.60 parsecs) away in the constellation Hercules. Due to their small separation, the two stars were initially detected from the radial velocity changes of GJ 3991, making the system a spectroscopic binary. 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 14.91 days. This system is the nearest example of a post-common-envelope binary.[9]
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.[12] In 1998, another group of astronomers was able to determine the secondary as a cold white dwarf star,[8] the compact remnant that remains after a low-mass star such as the Sun is no longer able to fuse elements for energy. It was directly detected for the first time, and spectroscopically confirmed as a white dwarf, in 2026.[11] GJ 3991 B is the 9th nearest white dwarf, after Sirius B, Procyon B, Van Maanen 2, Gliese 440, 40 Eridani B, Stein 2051 B, G 240-72, and LP 658-2.[13] Despite the close orbit of the white dwarf, it is not tidally locked, with a slow rotation period likely exceeding 100 days.[11]
Some sources call the component stars A & B,[12][13] while others call them Aa & Ab.[8]
See also
References
- ↑ 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.
- ↑ 2.0 2.1 2.2 2.3 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.
- ↑ 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.
- ↑ 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.
- ↑ 5.0 5.1 5.2 5.3 5.4 5.5 "G 203-47". SIMBAD. Centre de données astronomiques de Strasbourg. http://simbad.u-strasbg.fr/simbad/sim-basic?Ident=G+203-47.
- ↑ 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.
- ↑ 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.
- ↑ 8.0 8.1 8.2 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.
- ↑ 9.0 9.1 Shariat, Cheyanne; El-Badry, Kareem (March 2026). "A Global View of Post-interaction White Dwarf-main Sequence Binaries". Publications of the Astronomical Society of the Pacific 138 (3): 034202. doi:10.1088/1538-3873/ae453b. ISSN 0004-6280. Bibcode: 2026PASP..138c4202S.
- ↑ 10.0 10.1 10.2 Pineda, J. Sebastian; Youngblood, Allison; France, Kevin (1 September 2021). "The M-dwarf Ultraviolet Spectroscopic Sample. I. Determining Stellar Parameters for Field Stars". The Astrophysical Journal 918 (1): 40. doi:10.3847/1538-4357/ac0aea. Bibcode: 2021ApJ...918...40P.
- ↑ 11.0 11.1 11.2 11.3 11.4 11.5 11.6 11.7 O’Brien, Mairi W.; Wilson, David J. et al. (July 2026). "Direct detections of white dwarfs in four WD+dM post-common envelope binaries within 20 pc" (in en). Monthly Notices of the Royal Astronomical Society 550 (2). doi:10.1093/mnras/stag1195. ISSN 0035-8711.
- ↑ 12.0 12.1 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.
- ↑ 13.0 13.1 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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