Ross 154
Location of Ross 154 in the constellationSagittarius | |
Observation data EpochJ2000EquinoxJ2000 | |
---|---|
Constellation | Sagittarius |
Right ascension | 18h49m49.36378s[1] |
Declination | –23° 50′ 10.4474″[1] |
Apparent magnitude(V) | 10.44[2] |
Characteristics | |
Spectral type | M3.5V[2] |
B−Vcolor index | 1.76[3] |
Variable type | Flare star[4] |
Astrometry | |
Radial velocity(Rv) | −11.12±0.57[1]km/s |
Proper motion(μ) | RA:+639.368mas/yr[1] Dec.:–193.958mas/yr[1] |
Parallax(π) | 336.0266 ± 0.0317mas[1] |
Distance | 9.7063 ± 0.0009ly (2.9760 ± 0.0003pc) |
Absolute magnitude(MV) | 13.07[2] |
Details | |
Mass | 0.177 ± 0.004[5]M☉ |
Radius | 0.200 ± 0.008[5]R☉ |
Luminosity | 0.004015±0.000048[5]L☉ |
Surface gravity(logg) | 5.00 ± 0.05[6]cgs |
Temperature | 3,248+68 −66[5]K |
Metallicity[Fe/H] | -0.25[7]dex |
Rotation | 2.848 ± 0.001[8]days |
Rotational velocity(vsini) | 3.5 ± 1.5[7]km/s |
Age | under 1[7]Gyr |
Other designations | |
Database references | |
SIMBAD | data |
Ross 154(V1216 Sgr) is astarin the southernzodiacconstellationofSagittarius.It has anapparent visual magnitudeof 10.44,[2]making it much too faint to be seen with the naked eye. At a minimum, viewing Ross 154 requires a telescope with anapertureof 6.5 cm (3 in) under ideal conditions.[10]The distance to this star can be estimated fromparallaxmeasurements, which places it at 9.71light-years(2.98parsecs) away fromEarth.[1]It is the nearest star in the southern constellationSagittarius,and one of thenearest starsto the Sun.
Description
[edit]This star was first catalogued by American astronomerFrank Elmore Rossin 1925, and formed part of his fourth list of new variable stars.[11]In 1926, he added it to his second list of stars showing a measurableproper motionafter comparing its position with photographic plates taken earlier by fellow American astronomerE. E. Barnard.[12]A preliminaryparallaxvalue of0.362 ± 0.006arcsecondswas determined in 1937 by Walter O'Connell using photographic plates from the Yale telescope inJohannesburg,South Africa.This placed the star at the sixth position of the then-known nearby stars.[13]
![](https://upload.wikimedia.org/wikipedia/commons/thumb/9/9e/V1216SgrLightCurve.png/220px-V1216SgrLightCurve.png)
Ross 154 was found to be aUV Ceti-typeflare star,with a mean time between major flares of about two days.[4]The first such flare activity was observed from Australia in 1951 when the star increased in magnitude by 0.4.[15]Typically, the star will increase by 3–4 magnitudes during a flare.[16]The strength of the star's surfacemagnetic fieldis an estimated2.2 ± 0.1kG.[17]Ross 154 is anX-raysource and it has been detected by several X-ray observatories. The quiescent X-ray luminosity is about9 × 1027ergs s−1.[7]X-ray flare emission from this star has been observed byChandra observatory,with a particularly large flare emitting2.3 × 1033erg.[7]
Astellar classificationof M3.5V[2]makes this ared dwarfstar that is generating energy through thenuclear fusionof hydrogen at its core. It has an estimated 18% of theSun's massand 20% of theSun's radius,[5]but it is radiating only 0.4% of theluminosity of the Sun.[5]In contrast to the Sun where convection only occurs in the outer layers, a red dwarf with a mass this low will be entirelyconvective.[18]Based on the relatively highprojected rotation,this is probably a young star with an estimated age of less than a billion years.[7]The abundance of elements heavier than helium is about half that in the Sun.[7]
No low-mass companions have been discovered in orbit around Ross 154.[19]Nor does it display the level ofexcess infrared emissionthat would suggest the presence of circumstellar dust. Suchdebris disksare rare among M-type star systems older than about 10 million years, having been primarily cleared away by drag from thestellar wind.[20]Thespace velocitycomponents of this star in thegalactic coordinate systemare[U,V,W]= [–12.2, –1.0, –7.2]km s−1.[21]It has not been identified as a member of a specific stellarmoving group[22]and is orbiting through theMilky Waygalaxy at a distance from the core that varies from 27.65–30.66kly(8.48–9.40kpc) with anorbital eccentricityof 0.052.[23]Based on its low velocity relative to the Sun, this is believed to be a young disk (Population I) star.[24]This star will make its closest approach to the Sun in about 157,000 years, when it comes within 6.39 ± 0.10 ly (1.959 ± 0.031 pc).[25]
See also
[edit]References
[edit]- ^abcdefVallenari, 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.
- ^abcdeStaff (January 1, 2008),The One Hundred Nearest Star Systems,Research Consortium on Nearby Stars, archived fromthe originalon May 13, 2012,retrieved2008-06-12
- ^Corben, P. M.; et al. (1972), "U, B, V photometry of 500 southern stars",Monthly Notes of the Astronomical Society of South Africa,31:7–22,Bibcode:1972MNSSA..31....8C
- ^abJarrett, A. H.; Grabner, G. (1976), "On the Period Between Flares of V1216 Sagittarii",Information Bulletin on Variable Stars,1221(1221): 1,Bibcode:1976IBVS.1221....1J
- ^abcdefPineda, J. Sebastian; et al. (September 2021)."The M-dwarf Ultraviolet Spectroscopic Sample. I. Determining Stellar Parameters for Field Stars".The Astrophysical Journal.918(1): 23.arXiv:2106.07656.Bibcode:2021ApJ...918...40P.doi:10.3847/1538-4357/ac0aea.S2CID235435757.40.
- ^Mentuch, Erin; et al. (2008), "Lithium Depletion of Nearby Young Stellar Associations",The Astrophysical Journal,689(2): 1127–1140,arXiv:0808.3584,Bibcode:2008ApJ...689.1127M,doi:10.1086/592764,S2CID16859859
- ^abcdefgWargelin, B. J.; et al. (2008), "X-Ray Flaring on the dMe Star, Ross 154",The Astrophysical Journal,676(1): 610–627,arXiv:0712.2791,Bibcode:2008ApJ...676..610W,doi:10.1086/528702,S2CID53357714
- ^ Ibañez Bustos, R. V.; Buccino, A. P.; Messina, Sergio; Lanza, A. F.; Mauas, P. J. D. (December 2020), "Activity-rotation in the dM4 star Gl 729. A possible chromospheric cycle",Astronomy & Astrophysics,644,arXiv:2011.10391,Bibcode:2020A&A...644A...2I,doi:10.1051/0004-6361/202039164,S2CID226313606
- ^"V* V1216 Sgr -- Flare Star",SIMBAD,Centre de Données astronomiques de Strasbourg,retrieved2008-06-12
- ^Mills, H. Robert (1994),Practical Astronomy: A User-friendly Handbook for Skywatchers,Horwood Publishing, pp.199,ISBN1-898563-02-0
- ^Ross, Frank E. (1926), "New variable stars, (fourth list)",Astronomical Journal,37:91,Bibcode:1927AJ.....37Q..91R,doi:10.1086/104790
- ^Ross, Frank E. (February 1926), "New proper-motion stars, (second list)",Astronomical Journal,36(856): 124–128,Bibcode:1926AJ.....36..124R,doi:10.1086/104699
- ^O'Connell, Walter (February 1938), "A faint star of large parallax",Astronomical Journal,46(1078): 204,Bibcode:1938AJ.....46..204O,doi:10.1086/105447
- ^"MAST: Barbara A. Mikulski Archive for Space Telescopes".Space Telescope Science Institute.Retrieved8 December2021.
- ^Mayall, Margaret W. (February 1953), "Variable Star Notes",Journal of the Royal Astronomical Society of Canada,47:23–28,Bibcode:1953JRASC..47...23M
- ^Costa, R.; Cristaldi, S.; Rodono, M. (1970), "Cooperative Observations of the Flare Star V1216 Sgr",Information Bulletin on Variable Stars,461:1–4,Bibcode:1970IBVS..461....1C
- ^Reiners, Ansgar; Basri, Gibor (February 2007). "The First Direct Measurements of Surface Magnetic Fields on Very Low Mass Stars".The Astrophysical Journal.656(2): 1121–1135.arXiv:astro-ph/0610365.Bibcode:2007ApJ...656.1121R.doi:10.1086/510304.S2CID17743657.
- ^Reiners, Ansgar; Basri, Gibor (March 2009), "On the magnetic topology of partially and fully convective stars",Astronomy and Astrophysics,496(3): 787–790,arXiv:0901.1659,Bibcode:2009A&A...496..787R,doi:10.1051/0004-6361:200811450,S2CID15159121
- ^Hinz, Joannah L.; et al. (2002), "A Near-Infrared Wide-Field Proper Motion Search for Brown Dwarfs",The Astronomical Journal,123(4): 2027–2032,arXiv:astro-ph/0201140,Bibcode:2002AJ....123.2027H,doi:10.1086/339555,S2CID12737223
- ^Plavchan, Peter; Jura, M.; Lipscy, S. J. (October 2005), "Where Are the M Dwarf Disks Older Than 10 Million Years?",The Astrophysical Journal,631(2): 1161–1169,arXiv:astro-ph/0506132,Bibcode:2005ApJ...631.1161P,doi:10.1086/432568,S2CID3498251
- ^"Annotations on V* V1216 Sgr object".SIMBAD.Retrieved2010-04-18.
- ^Montes, D.; et al. (2001), "Late-type members of young stellar kinematic groups - I. Single stars",Monthly Notices of the Royal Astronomical Society,328(1): 45–63,arXiv:astro-ph/0106537,Bibcode:2001MNRAS.328...45M,doi:10.1046/j.1365-8711.2001.04781.x,S2CID55727428
- ^Allen, C.;Herrera, M. A. (1998), "The galactic orbits of nearby UV Ceti stars",Revista Mexicana de Astronomía y Astrofísica,34:37–46,Bibcode:1998larm.confE.115A
- ^Veeder, G. J. (1974), "Old disk flare stars",Astronomical Journal,79:702–704,Bibcode:1974AJ.....79..702V,doi:10.1086/111600
- ^Bobylev, V. V. (March 2010), "Searching for stars closely encountering with the solar system",Astronomy Letters,36(3): 220–226,arXiv:1003.2160,Bibcode:2010AstL...36..220B,doi:10.1134/S1063773710030060,S2CID118374161
External links
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