GJ 3991
| Observation data Epoch J2000.0 Equinox 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 mas/yr[2] Dec.: −274.501 mas/yr[2] |
| Parallax (π) | 131.5996±0.4285 mas[2] |
| 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 periastron (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 | |
| GJ 3991, HIP 83945, G 203-47, WD 1708+437, USNO 752[5] | |
| 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 of GJ 3991 A, but they 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. Bibcode:1987PASP...99..695R. doi:10.1086/132034. Constellation record for this object at VizieR.
- 1 2 3 4 5 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.
- ↑ Høg, E.; Fabricius, C.; Makarov, V. V.; Urban, S.; Corbin, T.; Wycoff, G.; Bastian, U.; Schwekendiek, P.; Wicenec, A. (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. arXiv:astro-ph/0112496. Bibcode:2002AJ....123.2002H. doi:10.1086/339315.
- 1 2 3 4 5 6 "G 203-47". SIMBAD. Centre de données astronomiques de Strasbourg.
- ↑ Fouqué, Pascal; Moutou, Claire; Malo, Lison; Martioli, Eder; Lim, Olivia; Rajpurohit, Arvind; Artigau, Etienne; Delfosse, Xavier; Donati, Jean-François; Forveille, Thierry; Morin, Julien; Allard, France; Delage, Raphaël; Doyon, René; Hébrard, Elodie; Neves, Vasco (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. arXiv:1712.04490. Bibcode:2018MNRAS.475.1960F. doi:10.1093/mnras/stx3246.
- ↑ Anderson, E.; Francis, Ch. (2012). "XHIP: An extended hipparcos compilation". Astronomy Letters. 38 (5): 331. arXiv:1108.4971. Bibcode:2012AstL...38..331A. doi:10.1134/S1063773712050015. XHIP record for this object at VizieR.
- 1 2 3 Delfosse, Xavier; et al. (April 1999), "New neighbours. I. 13 new companions to nearby M dwarfs", Astronomy and Astrophysics, 344: 897–910, arXiv:astro-ph/9812008, Bibcode:1999A&A...344..897D.
- 1 2 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. arXiv:2601.00439. Bibcode:2026PASP..138c4202S. doi:10.1088/1538-3873/ae453b. ISSN 0004-6280.
- 1 2 3 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. arXiv:2106.07656. Bibcode:2021ApJ...918...40P. doi:10.3847/1538-4357/ac0aea.
- 1 2 3 4 5 6 7 8 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". Monthly Notices of the Royal Astronomical Society. 550 (2). arXiv:2607.11320. doi:10.1093/mnras/stag1195. ISSN 0035-8711.
- 1 2 Reid, I. Neill; Gizis, John E. (June 1997). "Low-Mass Binaries and the Stellar Luminosity Function". The Astronomical Journal. 113: 2246. Bibcode:1997AJ....113.2246R. doi:10.1086/118436. ISSN 0004-6256.
- 1 2 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, arXiv:2104.14972, Bibcode:2021A&A...650A.201R, doi:10.1051/0004-6361/202140985, S2CID 233476431 Data available at https://gruze.org/10pc/ Archived 12 March 2023 at the Wayback Machine
