Astronomy:LO Pegasi

From HandWiki
Short description: Star in the constellation Pegasus
LO Pegasi
LOPegLightCurve.png
A visual band light curve for LO Pegasi. The main plot (adapted from Karmakar et al.[1]) shows the long-term variability. Inset plot "A" (adapted from Kiraga[2]) shows the periodic variability, and inset "B" (also adapted from Karmakar et al.[1]) shows a flare.
Observation data
Equinox J2000.0]] (ICRS)
Constellation Pegasus
Right ascension  21h 31m 01.714s[3]
Declination 23° 20′ 07.37″[3]
Apparent magnitude (V) 9.23[4] (9.04 to 9.27)[5]
Characteristics
Spectral type K3Vke[6]
B−V color index 1.050±0.015[4]
Variable type BY Dra[5]
Astrometry
Radial velocity (Rv)−23.36±1.75[7] km/s
Proper motion (μ) RA: 134.654[3] mas/yr
Dec.: −144.889[3] mas/yr
Parallax (π)41.2912 ± 0.0169[3] mas
Distance78.99 ± 0.03 ly
(24.218 ± 0.010 pc)
Absolute magnitude (MV)7.26[4]
Details[8]
Mass0.66±0.02 M☉
Radius0.72±0.10 R☉
Luminosity0.25±0.02 L☉
Surface gravity (log g)4.5±0.5 cgs
Temperature4,750±250 K
Rotation0.4236 d[9]
Rotational velocity (v sin i)48.2±2.5[10] km/s
Age10–300[11] Myr
Other designations
LO Peg, BD+22 4409, GJ 4199, HIP 106231, WDS J21310+2320A[12]
Database references
SIMBADdata

LO Pegasi is a single star[13] in the northern constellation of Pegasus that has been the subject of numerous scientific studies.[14] LO Pegasi, abbreviated LO Peg, is the variable star designation. It is too faint to be viewed with the naked eye, having an apparent visual magnitude that ranges from 9.04 down to 9.27.[5] Based on parallax measurements, LO Peg is located at a distance of 79 light years from the Sun. It is a member of the young AB Doradus moving group,[13][11] and is drifting closer with a radial velocity of −23 km/s.[7]

This is a K-type main-sequence star with a stellar classification of K3Vke,[6] where the 'k' suffix indicates interstellar absorption lines and 'e' means there are emission lines in the spectrum. It became of interest to astronomers when significant X-ray emission was detected from this star in 1994. R. D. Jeffries and associates reported flare activity based on a rotationally-broadened hydrogen α emission line and found the star varied in brightness.[15]

LO Peg is an ultrafast rotator, completing a full rotation every 10.15 hours.[16] It is classified as a BY Draconis variable that is magnetically active and has star spots. The combination of non-uniform surface brightness and rotation makes it appear to vary in luminosity.[5] Up to 25.7% of the surface is covered in spots. Long term changes in periodicity suggest activity cycles, similar to the solar cycle,[1] with periods of approximately 3 and 7.4 years.[11] The element lithium has been detected in its atmosphere, whose abundance, in combination with the star's rapid rotation, indicates this is a young star with an age of no more than a few hundred million years.[15]

See also

References

  1. ↑ 1.0 1.1 1.2 Karmakar, Subhajeet et al. (July 2016), "LO Peg: surface differential rotation, flares, and spot-topographic evolution", Monthly Notices of the Royal Astronomical Society 459 (3): 3112–3129, doi:10.1093/mnras/stw855, Bibcode: 2016MNRAS.459.3112K. 
  2. ↑ Kiraga, M. (March 2012). "ASAS Photometry of ROSAT Sources. I. Periodic Variable Stars Coincident with Bright Sources from the ROSAT All Sky Survey". Acta Astronomica 62 (1): 67–95. Bibcode: 2012AcA....62...67K. http://acta.astrouw.edu.pl/Vol62/n1/pdf/pap_62_1_4.pdf. Retrieved 23 June 2022. 
  3. ↑ 3.0 3.1 3.2 3.3 Brown, A. G. A. (2021). "Gaia Early Data Release 3: Summary of the contents and survey properties". Astronomy & Astrophysics 649: A1. doi:10.1051/0004-6361/202039657. Bibcode: 2021A&A...649A...1G.  Gaia EDR3 record for this source at VizieR.
  4. ↑ 4.0 4.1 4.2 Anderson, E.; Francis, Ch. (2012), "XHIP: An extended hipparcos compilation", Astronomy Letters 38 (5): 331, doi:10.1134/S1063773712050015, Bibcode: 2012AstL...38..331A. 
  5. ↑ 5.0 5.1 5.2 5.3 Samus', N. N et al. (2017), "General catalogue of variable stars", Astronomy Reports, GCVS 5.1 61 (1): 80, doi:10.1134/S1063772917010085, Bibcode: 2017ARep...61...80S. 
  6. ↑ 6.0 6.1 Gray, R. O. et al. (2003), "Contributions to the Nearby Stars (NStars) Project: Spectroscopy of Stars Earlier than M0 within 40 Parsecs: The Northern Sample. I", The Astronomical Journal 126 (4): 2048, doi:10.1086/378365, Bibcode: 2003AJ....126.2048G. 
  7. ↑ 7.0 7.1 Brown, A. G. A. (August 2018). "Gaia Data Release 2: Summary of the contents and survey properties". Astronomy & Astrophysics 616: A1. doi:10.1051/0004-6361/201833051. Bibcode: 2018A&A...616A...1G.  Gaia DR2 record for this source at VizieR.
  8. ↑ Pandey, J. C. et al. (September 2005), "Optical and X-Ray Studies of Chromospherically Active Stars: FR Cancri, HD 95559, and LO Pegasi", The Astronomical Journal 130 (3): 1231–1246, doi:10.1086/432539, Bibcode: 2005AJ....130.1231P. 
  9. ↑ Strassmeier, Klaus G. (September 2009), "Starspots", The Astronomy and Astrophysics Review 17 (3): 251–308, doi:10.1007/s00159-009-0020-6, Bibcode: 2009A&ARv..17..251S. 
  10. ↑ Frasca, A. et al. (May 1, 2018), "A spectroscopic survey of the youngest field stars in the solar neighborhood . II. The optically faint sample", Astronomy and Astrophysics 612: A96, doi:10.1051/0004-6361/201732028, ISSN 0004-6361, Bibcode: 2018A&A...612A..96F. 
  11. ↑ 11.0 11.1 11.2 Savanov, I. S. et al. (September 2016), "Photometric Observations of LO Peg in 2014-2015", Acta Astronomica 66 (3): 381–390, Bibcode: 2016AcA....66..381S. 
  12. ↑ "LO Peg". SIMBAD. Centre de données astronomiques de Strasbourg. http://simbad.u-strasbg.fr/simbad/sim-basic?Ident=LO+Peg. 
  13. ↑ 13.0 13.1 Azulay, R. et al. (June 2017), "Young, active radio stars in the AB Doradus moving group", Astronomy & Astrophysics 602: 15, doi:10.1051/0004-6361/201629899, A57, Bibcode: 2017A&A...602A..57A. 
  14. ↑ Savanov, I. et al. (May 2019), "Activity of rapidly rotating dwarf LO Peg an [sic] giant FK Com", Contributions of the Astronomical Observatory Skalnaté Pleso 49 (2): 415–419, Bibcode: 2019CoSka..49..415S. 
  15. ↑ 15.0 15.1 Jeffries, R. D. et al. (September 1994), "BD +22 4409 : a rapidly rotating, low-mass member of the Local Association", Monthly Notices of the Royal Astronomical Society 270: 153–172, doi:10.1093/mnras/270.1.153, Bibcode: 1994MNRAS.270..153J. 
  16. ↑ Lalitha, S. et al. (February 10, 2017), "Structure and variability in the corona of the ultrafast rotator LO Pegasi", Astronomy & Astrophysics 602: 11, doi:10.1051/0004-6361/201629482, A26, Bibcode: 2017A&A...602A..26L. 

Further reading

  • Savanov, I. S. et al. (July 2018), "Photometric Observations of LO Peg in 2017", Astrophysical Bulletin 73 (3): 344–350, doi:10.1134/S1990341318030082, Bibcode: 2018AstBu..73..344S. 
  • Pandey, S. B. et al. (December 2014), "Long-term spot topography and multi-band flare analysis of active ultra-fast rotator LO Peg", Proceedings of Swift: 10 Years of Discovery (SWIFT 10), held 2-5 December 2014 at La Sapienza University, Rome, Italy: p. 155, doi:10.22323/1.233.0155, Bibcode: 2014styd.confE.155P. 
  • Pandey, J. C. et al. (August 2011), "Optical polarimetry and photometry of young sun-like star LO Peg", The Physics of Sun and Star Spots, Proceedings of the International Astronomical Union, IAU Symposium 273: pp. 455–459, doi:10.1017/S1743921311015766, Bibcode: 2011IAUS..273..455P. 
  • Taš, G. (January 2011), "Long-term photometry of the ultra-fast rotator LO Peg", Astronomische Nachrichten 332 (1): 57–64, doi:10.1002/asna.201011487, Bibcode: 2011AN....332...57T. 
  • Pandey, J. C. et al. (June 2009), "LO Pegasi: an investigation of multiband optical polarization", Monthly Notices of the Royal Astronomical Society 396 (2): 1004–1011, doi:10.1111/j.1365-2966.2009.14762.x, Bibcode: 2009MNRAS.396.1004P. 
  • Barnes, J. R. et al. (February 2005), "LO Peg in 1998: star-spot patterns and differential rotation", Monthly Notices of the Royal Astronomical Society 356 (4): 1501–1508, doi:10.1111/j.1365-2966.2004.08588.x, Bibcode: 2005MNRAS.356.1501B. 
  • Harmon, R. O.; Saranathan, V. (December 2004), "Spot topography of BD+22o 4409 (LO Peg) using Matrix Light-curve Inversion", Bulletin of the American Astronomical Society 36: 1361, Bibcode: 2004AAS...205.1410H. 
  • Piluso, N. et al. (June 2008), "Doppler imaging of the young late-type star LO Pegasi (BD+22°4409) in 2003 September", Monthly Notices of the Royal Astronomical Society 387 (1): 237–246, doi:10.1111/j.1365-2966.2008.13153.x, Bibcode: 2008MNRAS.387..237P. 
  • Csorvási, R. (September 2006), Forgács-Dajka, E., ed., "Photometry of LO Pegasi in B, V, R colors", Proceedings of the 4th Workshop of Young Researchers in Astronomy & Astrophysics; Budapest, Hungary, 11-13 January, 2006 (Astronomy Department of the Eötvös University (PADEU)) 17: p. 95, Bibcode: 2006PADEU..17...95C. 
  • Pandey, J. C. et al. (September 2005), "Optical and X-Ray Studies of Chromospherically Active Stars: FR Cancri, HD 95559, and LO Pegasi", The Astronomical Journal 130 (3): 1231–1246, doi:10.1086/432539, Bibcode: 2005AJ....130.1231P. 
  • Barnes, J. R. et al. (February 2005), "LO Peg in 1998: star-spot patterns and differential rotation", Monthly Notices of the Royal Astronomical Society 356 (4): 1501–1508, doi:10.1111/j.1365-2966.2004.08588.x, Bibcode: 2005MNRAS.356.1501B. 
  • Harmon, R. O.; Saranathan, V. (December 2004), "Spot topography of BD+22o 4409 (LO Peg) using Matrix Light-curve Inversion", Bulletin of the American Astronomical Society 36: 1361, Bibcode: 2004AAS...205.1410H. 
  • Dal, H. A.; Tas, G. (March 2003), "New Photoelectric Photometry of the Young Star LO Pegasi", Information Bulletin on Variable Stars 5390 (1): 1, Bibcode: 2003IBVS.5390....1D. 
  • Lister, T. A. et al. (August 1999), "Doppler imaging of BD+22° 4409 (LO Peg) using least-squares deconvolution", Monthly Notices of the Royal Astronomical Society 307 (3): 685–694, doi:10.1046/j.1365-8711.1999.02662.x, Bibcode: 1999MNRAS.307..685L. 
  • Eibe, M. T. et al. (January 1999), "Evidence for large-scale, global mass inflow and flaring on the late-type fast rotator BD+22 deg 4409", Astronomy and Astrophysics 341: 527–538, Bibcode: 1999A&A...341..527E. 
  • Robb, R. M.; Cardinal, R. D. (August 1995), "Optical Observations of the Active Star RE J2131+233", Information Bulletin on Variable Stars 4221 (1): 1, Bibcode: 1995IBVS.4221....1R. 



Retrieved from "https://handwiki.org/wiki/index.php?title=Astronomy:LO_Pegasi&oldid=3355128"