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Ross 154

Coordinates:Sky map18h49m49.3625s,−23° 50′ 10.437″
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Ross 154
Ross 154 is located in the constellation Sagittarius.
Ross 154 is located in the constellation Sagittarius.
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]
Distance9.7063 ± 0.0009ly
(2.9760 ± 0.0003pc)
Absolute magnitude(MV)13.07[2]
Details
Mass0.177 ± 0.004[5]M☉
Radius0.200 ± 0.008[5]R☉
Luminosity0.004015±0.000048[5]L☉
Surface gravity(logg)5.00 ± 0.05[6]cgs
Temperature3,248+68
−66[5]K
Metallicity[Fe/H]-0.25[7]dex
Rotation2.848 ± 0.001[8]days
Rotational velocity(vsini)3.5 ± 1.5[7]km/s
Ageunder 1[7]Gyr
Other designations
CD−23° 14742,GCTP4338,GJ729,HIP92403,LHS3414, V1216 Sagittarii.[9]
Database references
SIMBADdata

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

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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]

A broadband opticallight curvefor V1216 Sagittarii, plotted fromKeplerdata[14]

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

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References

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  1. ^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.
  2. ^abcdeStaff (January 1, 2008),The One Hundred Nearest Star Systems,Research Consortium on Nearby Stars, archived fromthe originalon May 13, 2012,retrieved2008-06-12
  3. ^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
  4. ^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
  5. ^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.
  6. ^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
  7. ^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
  8. ^ 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
  9. ^"V* V1216 Sgr -- Flare Star",SIMBAD,Centre de Données astronomiques de Strasbourg,retrieved2008-06-12
  10. ^Mills, H. Robert (1994),Practical Astronomy: A User-friendly Handbook for Skywatchers,Horwood Publishing, pp.199,ISBN1-898563-02-0
  11. ^Ross, Frank E. (1926), "New variable stars, (fourth list)",Astronomical Journal,37:91,Bibcode:1927AJ.....37Q..91R,doi:10.1086/104790
  12. ^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
  13. ^O'Connell, Walter (February 1938), "A faint star of large parallax",Astronomical Journal,46(1078): 204,Bibcode:1938AJ.....46..204O,doi:10.1086/105447
  14. ^"MAST: Barbara A. Mikulski Archive for Space Telescopes".Space Telescope Science Institute.Retrieved8 December2021.
  15. ^Mayall, Margaret W. (February 1953), "Variable Star Notes",Journal of the Royal Astronomical Society of Canada,47:23–28,Bibcode:1953JRASC..47...23M
  16. ^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
  17. ^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.
  18. ^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
  19. ^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
  20. ^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
  21. ^"Annotations on V* V1216 Sgr object".SIMBAD.Retrieved2010-04-18.
  22. ^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
  23. ^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
  24. ^Veeder, G. J. (1974), "Old disk flare stars",Astronomical Journal,79:702–704,Bibcode:1974AJ.....79..702V,doi:10.1086/111600
  25. ^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
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