Gliese 65
  Gliese 65 Location of Gliese 65 in the constellationCetus | |
| Observation data EpochJ2000.0EquinoxJ2000.0 | |
|---|---|
| Constellation | Cetus |
| Gliese 65 A (BL Ceti) | |
| Right ascension | 01h39m01.3773s[1] |
| Declination | –17° 57′ 02.587″[1] |
| Apparent magnitude(V) | 12.8[2] |
| Gliese 65 B (UV Ceti) | |
| Right ascension | 01h39m01.6377s[3] |
| Declination | –17° 57′ 01.001″[3] |
| Apparent magnitude(V) | 12.8[2] |
| Characteristics | |
| Gliese 65 A (BL Ceti) | |
| Spectral type | M5.5V[4] |
| U−Bcolor index | 1.10 |
| B−Vcolor index | 1.87 |
| Variable type | UV Cet[5] |
| Gliese 65 B (UV Ceti) | |
| Spectral type | M6 V[4] |
| Variable type | UV Cet[6] |
| Astrometry | |
| Parallax(π) | 371.92 ± 0.42mas[7] |
| Distance | 8.770 ± 0.010ly (2.689 ± 0.003pc) |
| Gliese 65 A (BL Ceti) | |
| Proper motion(μ) | RA:3385.316[1]mas/yr Dec.:544.386[1]mas/yr |
| Absolute magnitude(MV) | 15.7[2] |
| Gliese 65 B (UV Ceti) | |
| Proper motion(μ) | RA:3178.694[3]mas/yr Dec.:584.061[3]mas/yr |
| Absolute magnitude(MV) | 15.7[2] |
| Orbit[7] | |
| Period(P) | 26.38±0.002yr |
| Semi-major axis(a) | 2.0584±0.0097[8]" (5.459±0.002AU) |
| Eccentricity(e) | 0.6172±0.0001 |
| Inclination(i) | 128.0±0.1° |
| Longitude of the node(Ω) | 325.9±0.1° |
| Periastronepoch(T) | 41333±8MJD (17 January 1972) |
| Argument of periastron(ω) (secondary) | 103.2±0.1° |
| Details | |
| Gliese 65 A | |
| Mass | 0.122±0.002[7]M☉ |
| Radius | 0.165±0.006[8]R☉ |
| Luminosity | 0.00147±0.00005[9]L☉ |
| Surface gravity(logg) | 5.092±0.015[8]cgs |
| Temperature | 2784±58[9]K |
| Metallicity[Fe/H] | −0.03±0.20[8]dex |
| Rotation | 0.2430±0.0005[10]days |
| Rotational velocity(vsini) | 28.2±2[8]km/s |
| Gliese 65 B | |
| Mass | 0.116±0.002[7]M☉ |
| Radius | 0.159±0.006[8]R☉ |
| Luminosity | 0.00125±0.00005[9]L☉ |
| Surface gravity(logg) | 5.113±0.015[8]cgs |
| Temperature | 2728±60[9]K |
| Metallicity[Fe/H] | −0.12±0.20[8]dex |
| Rotation | 0.2268±0.0003[10]days |
| Rotational velocity(vsini) | 30.6±2[8]km/s |
| Other designations | |
| Gliese 65 A:BL Ceti,LHS9 | |
| Gliese 65 B:UV Ceti,LHS10 | |
| Database references | |
| SIMBAD | The system |
| A (BL Cet) | |
| B (UV Cet) | |
Gliese 65,also known asLuyten 726-8,is abinary star systemthat is one of Earth'snearest neighbors,at 8.8light-years(2.7parsecs) fromEarthin theconstellationCetus.The two component stars are bothflare starswith thevariable star designationsBL CetiandUV Ceti.
Star system
[edit]
The star system was discovered in 1948 byWillem Jacob Luytenin the course of compiling a catalog of stars of highproper motion;he noted its exceptionally high proper motion of 3.37 arc seconds annually and cataloged it as Luyten 726-8.[11]The two stars are of nearly equal brightness, with visual magnitudes of 12.7 and 13.2 as seen from Earth. They orbit one another every 26.5 years. The distance between the two stars varies from 2.1 to 8.8astronomical units(310 to 1,320Gm). The Gliese 65 system is approximately 2.63parsecs(8.58ly) fromEarth'sSolar System,in theconstellationCetus,and is thus the seventh-closest star system to Earth. Its own nearest neighbor isTau Ceti,0.98 pc (3.20 ly) away from it. Ifkm/s then approximately 28,700 years ago Gliese 65 was at its minimal distance of 2.21pc(7.2 ly) from the Sun.[12]
Gliese 65 A was later found to be avariable starand given the variable star designation BL Ceti.[5]It is ared dwarfofspectral typeM5.5V. It is also a flare star, and classified as aUV Ceti variabletype, but it is not nearly as remarkable or extreme in its behavior as its companion star UV Ceti.
Soon after the discovery of Gliese 65 A, the companion star Gliese 65 B was discovered. Like Gliese 65 A, this star was also found to be variable and given the variable star designation UV Ceti.[6]Although UV Ceti was not the first flare star discovered, it is the most prominent example of such a star, so similar flare stars are now classified as UV Ceti type variable stars. This star goes through fairly extreme changes of brightness: for instance, in 1952, its brightness increased by 75 times in only 20 seconds. UV Ceti is ared dwarfofspectral typeM6V.[4]
Both stars are listed as spectral standard stars for their respective classes, being considered typical examples of the classes.[4]
In approximately 31,500 years, Gliese 65 will have a close encounter withEpsilon Eridaniat the minimal distance of about 0.93ly.Gliese 65 can penetrate a conjecturedOort cloudabout Epsilon Eridani, which may gravitationallyperturbsome long-periodcomets.The duration of mutual transit of two star systems within 1lyfrom each other is about 4,600 years.[14]
Gliese 65 is a possible member of theHyades Stream.[15]
Candidate planet
[edit]In 2024, a candidatesuper-Neptune-mass planet was detected in the Gliese 65 system viaastrometrywithVery Large Telescope's GRAVITY instrument. If it exists, it would orbit one of the two stars (it is unclear which) with a period of 156 days.[7]The planet's properties change slightly depending on which star it orbits, but in general its mass is estimated to be about 40MEand thesemi-major axisis about 30% of anastronomical unit.It is estimated to be seven times larger than Earth based on mass-radius relationships.[7]
| Companion (in order from star) |
Mass | Semimajor axis (AU) |
Orbital period (days) |
Eccentricity | Inclination | Radius |
|---|---|---|---|---|---|---|
| b(unconfirmed) | 39±7M🜨 36±6M🜨 |
0.283±0.002 0.274±0.002 |
156±1 | 0.33±0.30 0.27±0.21 |
88±6° 89±9° |
~7[note 1]R🜨 |
Notes
[edit]- ^The parameters are slightly different depending on whether the planet orbits star A (above) or star B (below).
- ^estimated based on mass-radius relationships.
References
[edit]- ^abcdVallenari, A.; et al. (Gaia collaboration) (2023)."GaiaData 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.S2CID244398875. Gaia DR3 record for this sourceatVizieR.
- ^abcdHoudebine, Éric R.; Mullan, D. J.; Doyle, J. G.; de la Vieuville, Geoffroy; Butler, C. J.; Paletou, F. (2019)."The Mass-Activity Relationships in M and K Dwarfs. I. Stellar Parameters of Our Sample of M and K Dwarfs".The Astronomical Journal.158(2): 56.arXiv:1905.07921.Bibcode:2019AJ....158...56H.doi:10.3847/1538-3881/ab23fe.S2CID159041104.
- ^abcdVallenari, A.; et al. (Gaia collaboration) (2023)."GaiaData 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.S2CID244398875. Gaia DR3 record for this sourceatVizieR.
- ^abcdKirkpatrick, J. Davy; Henry, Todd J.; McCarthy, Donald W. Jr. (1991)."A standard stellar spectral sequence in the red/near-infrared - Classes K5 to M9".Astrophysical Journal Supplement.77:417.Bibcode:1991ApJS...77..417K.doi:10.1086/191611.
- ^ab"Query= BL Cet".General Catalogue of Variable Stars.Centre de Données astronomiques de Strasbourg.Archivedfrom the original on 2016-03-03.Retrieved2009-12-16.
- ^ab"Query= UV Cet".General Catalogue of Variable Stars.Centre de Données astronomiques de Strasbourg.Archivedfrom the original on 2016-03-03.Retrieved2009-12-16.
- ^abcdefgAbuter, R.; et al. (GRAVITY Collaboration) (May 2024). "Astrometric detection of a Neptune-mass candidate planet in the nearest M-dwarf binary system GJ65 with VLTI/GRAVITY".Astronomy & Astrophysics.685:L9.arXiv:2404.08746.Bibcode:2024A&A...685L...9G.doi:10.1051/0004-6361/202449547.
- ^abcdefghi Kervella, Pierre; et al. (October 2016), "The red dwarf pair GJ65 AB: inflated, spinning twins of Proxima. Fundamental parameters from PIONIER, NACO, and UVES observations",Astronomy & Astrophysics,593,arXiv:1607.04351,Bibcode:2016A&A...593A.127K,doi:10.1051/0004-6361/201628631
- ^abcd MacDonald, James; et al. (June 2018), "The Magnetic Binary GJ 65: A Test of Magnetic Diffusivity Effects",The Astrophysical Journal,860(1): 15,arXiv:1711.09434,Bibcode:2018ApJ...860...15M,doi:10.3847/1538-4357/aac2c0
- ^ab Barnes, J. R.; et al. (October 2017), "Surprisingly different star-spot distributions on the near equal-mass equal-rotation-rate stars in the M dwarf binary GJ 65 AB",Monthly Notices of the Royal Astronomical Society,471(1): 811–823,arXiv:1706.03979,Bibcode:2017MNRAS.471..811B,doi:10.1093/mnras/stx1482
- ^Luyten, W. J. (December 1949)."New stars with proper motions exceeding 0.5" annually ".The Astronomical Journal.55:15.Bibcode:1949AJ.....55...15L.doi:10.1086/106322.
- ^"Annotations on V* UV Cet object".Centre de Données astronomiques de Strasbourg.Archivedfrom the original on 2014-11-23.Retrieved2010-04-14.
- ^Beskin, G.; Karpov, S.; Plokhotnichenko, V.; Stepanov, A.; Tsap, Yu. (January 2017)."Discovery of the subsecond linearly polarized spikes of synchrotron origin in the UV Ceti giant optical flare".Publications of the Astronomical Society of Australia.34.arXiv:1702.06660.Bibcode:2017PASA...34...10B.doi:10.1017/pasa.2017.3.S2CID125084280.
- ^Potemine, Igor Yu. (April 2010). "Transit of Luyten 726-8 within 1 ly from Epsilon Eridani".arXiv:1004.1557[astro-ph.SR].
- ^Montes, D.; et al. (2001)."Late-type members of young stellar kinematic groups - I. Single stars".MNRAS.328(1): 45–63.arXiv:astro-ph/0106537.Bibcode:2001MNRAS.328...45M.doi:10.1046/j.1365-8711.2001.04781.x.S2CID55727428.
Further reading
[edit]- Durand, E.; Oberly, J. J.; Tousey, R. (1949). "Analysis of the First Rocket Ultraviolet Solar Spectra".The Astrophysical Journal.109:1.Bibcode:1949ApJ...109....1D.doi:10.1086/145099.
- Luyten, W. J. (1949)."New stars with proper motions exceeding 0.5" annually ".The Astronomical Journal.55:15.Bibcode:1949AJ.....55...15L.doi:10.1086/106322.
- Geyer, David W.; Harrington, Robert S.; Worley, Charles E. (June 1988)."Parallax, orbit, and mass of the visual binary L726-8".Astronomical Journal.95:1841–1842.Bibcode:1988AJ.....95.1841G.doi:10.1086/114781.
- Delfosse, Xavier; et al. (December 2000). "Accurate masses of very low mass stars. IV. Improved mass-luminosity relations".Astronomy and Astrophysics.364:217–224.arXiv:astro-ph/0010586.Bibcode:2000A&A...364..217D.
External links
[edit]- http://www.aavso.org/vstar/vsots/fall03.shtmlArchived2004-03-05 at theWayback Machine
- http://www.solstation.com/stars/luy726-8.htmArchived2009-03-27 at theWayback Machine
