Astronomy:LN Andromedae

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Short description: Star in the constellation Andromeda
LN Andromedae
LNAndLightCurve.png
A light curve for LN Andromedae, plotted from Hipparcos data[1]
Observation data
{{#ifeq:J2000.0|J2000.0 (ICRS)|Epoch J2000.0      Equinox J2000.0 (ICRS)| Epoch J2000.0      [[Astronomy:Equinox (celestial coordinates)|Equinox J2000.0}}
Constellation Andromeda
LN Andromedae A
Right ascension  23h 02m 45.14786s[2]
Declination +44° 03′ 31.4984″[2]
Apparent magnitude (V) 6.37[3]
LN Andromedae B
Right ascension  23h 02m 45.60328s[4]
Declination +44° 03′ 37.2673″[4]
Apparent magnitude (V) 9.88[5]
Characteristics
A
Spectral type B2V[6]
Apparent magnitude (U) 5.8[7]
Apparent magnitude (B) 6.377[8]
Apparent magnitude (J) 6.368[9]
Apparent magnitude (H) 6.482[9]
Apparent magnitude (K) 6.496[9]
Variable type SPB?[10]
B
Spectral type A1V[11]
Astrometry
LN Andromedae A
Radial velocity (Rv)−11.30±0.1[12] km/s
Proper motion (μ) RA: 0.441±0.019[2] mas/yr
Dec.: −5.799±0.027[2] mas/yr
Parallax (π)2.1847 ± 0.0280[2] mas
Distance1,490 ± 20 ly
(458 ± 6 pc)
Absolute magnitude (MV)−1.66[13]
LN Andromedae B
Proper motion (μ) RA: 0.238±0.012[4] mas/yr
Dec.: −5.813±0.016[4] mas/yr
Parallax (π)2.2005 ± 0.0182[4] mas
Distance1,480 ± 10 ly
(454 ± 4 pc)
Details
A
Mass6.5[14] M☉
Radius3.1[15] R☉
Luminosity608[15] L☉
Surface gravity (log g)3.94±0.13[14] cgs
Temperature18090±730[14] K
Metallicity [Fe/H]−0.23[16] dex
Rotational velocity (v sin i)8±4[14] km/s
Age9.5±4.8[17] Myr
B
Mass2.1[16] M☉
Radius2.0[18] R☉
Luminosity13[19] L☉
Surface gravity (log g)4.1[16] cgs
Temperature9,843[16] K
Metallicity [Fe/H]−0.33[16] dex
Other designations
2MASS J23024514+4403314, HR 8768, BD+43°4378, HD 217811, SAO 52626, PPM 63745, HIP 113802, WDS J23028+4404AB
Database references
SIMBADdata

LN Andromedae (LN And), also known as HD 217811, HR 8768, is a formerly suspected variable star[6] in the constellation Andromeda. Located approximately 458 parsecs (1,490 ly) away from Earth,[2] it shines with an apparent visual magnitude 6.41, thus it can be seen by the naked eye under very favourable conditions. Its spectral classification is B2V, meaning that it's a hot main sequence star, emitting light approximately with a blackbody spectrum at an effective temperature of 18,090 K.[14]

Companion

In the Washington Double Star Catalog LN And has a faint optical companion star with an apparent magnitude of 9.88,[5] 7.5″ from LN And. The separation has increased from 4.0″ when it was discovered as a double in 1828.[20] The two stars share the same Hipparcos identifier HIP 113802, and have very similar parallaxes and proper motions.[2][4]

Variability

In 1979, the blue magnitude of LN And was reported to vary by about 0.025 every 28 minutes. Such variability was not known for any class of variable, but the position in the Hertzsprung–Russell diagram at the main sequence (low luminosity) end of the same instability strip as the β Cephei stars would make high-overtone radial pulsations the likely cause.[13] LN And was added to the General Catalogue of Variable Stars as LN Andromedae,[6] but follow-up studies failed to find the same rapid variations, or any significant variations in brightness and it is now listed as probably constant.[21][6]

Analysis of Hipparcos photometry shows variability of about 0.0059 magnitudes with a main period of 3.25 d. The statistical threshold for these variations is at a level which is only met by 0.01% of stars.[3]

References

  1. ↑ "/ftp/cats/more/HIP/cdroms/cats". Strasbourg astronomical Data Center. https://cdsarc.cds.unistra.fr/viz-bin/ftp-index?/ftp/cats/more/HIP/cdroms/cats. 
  2. ↑ 2.0 2.1 2.2 2.3 2.4 2.5 2.6 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.
  3. ↑ 3.0 3.1 Koen, Chris; Eyer, Laurent (2002). "New periodic variables from the Hipparcos epoch photometry". Monthly Notices of the Royal Astronomical Society 331 (1): 45. doi:10.1046/j.1365-8711.2002.05150.x. Bibcode: 2002MNRAS.331...45K. 
  4. ↑ 4.0 4.1 4.2 4.3 4.4 4.5 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.
  5. ↑ 5.0 5.1 "BD+43 4378B". SIMBAD. Centre de données astronomiques de Strasbourg. http://simbad.u-strasbg.fr/simbad/sim-basic?Ident=BD%2B43+4378B. 
  6. ↑ 6.0 6.1 6.2 6.3 "LN And database entry". Combined General Catalog of Variable Stars. CDS. http://webviz.u-strasbg.fr/viz-bin/VizieR-S?V*%20LN%20And. 
  7. ↑ Reed, B. C. (May 2003). "Catalog of Galactic OB Stars". The Astronomical Journal 125 (5): 2531–2533. doi:10.1086/374771. Bibcode: 2003AJ....125.2531R. 
  8. ↑ "LN Andromedae". SIMBAD. Centre de données astronomiques de Strasbourg. http://simbad.u-strasbg.fr/simbad/sim-basic?Ident=LN+Andromedae. 
  9. ↑ 9.0 9.1 9.2 Cutri, Roc M.; Skrutskie, Michael F.; Van Dyk, Schuyler D.; Beichman, Charles A.; Carpenter, John M.; Chester, Thomas; Cambresy, Laurent; Evans, Tracey E. et al. (2003). "VizieR Online Data Catalog: 2MASS All-Sky Catalog of Point Sources (Cutri+ 2003)". CDS/ADC Collection of Electronic Catalogues 2246: II/246. Bibcode: 2003yCat.2246....0C. http://vizier.u-strasbg.fr/viz-bin/VizieR?-source=II/246. 
  10. ↑ "LN Andromedae". https://www.aavso.org/vsx/index.php?view=detail.top&oid=262. 
  11. ↑ Lutz, T. E.; Lutz, J. H. (June 1977). "Spectral classification and UBV photometry of bright visual double stars". Astronomical Journal 82: 431–434. doi:10.1086/112066. Bibcode: 1977AJ.....82..431L. 
  12. ↑ Gontcharov, G. A. (November 2006). "Pulkovo Compilation of Radial Velocities for 35 495 Hipparcos stars in a common system". Astronomy Letters 32 (11): 759–771. doi:10.1134/S1063773706110065. Bibcode: 2006AstL...32..759G. 
  13. ↑ 13.0 13.1 Jakate, S. M. (1979). "A new class of early-type ultra-short-period variables". The Astronomical Journal 84: 1042. doi:10.1086/112510. Bibcode: 1979AJ.....84.1042J. 
  14. ↑ 14.0 14.1 14.2 14.3 14.4 Lyubimkov, N.; Lambert, D. L.; Poklad, D. B.; Rachkovskaya, T. M.; Rostopchin, S. I. (February 2013). "Carbon, nitrogen and oxygen abundances in atmospheres of the 5-11 M☉ B-type main-sequence stars". Monthly Notices of the Royal Astronomical Society 428 (4): 3497–3508. doi:10.1093/mnras/sts287. Bibcode: 2013MNRAS.428.3497L. 
  15. ↑ 15.0 15.1 Stassun, Keivan G. et al. (September 2018). "The TESS Input Catalog and Candidate Target List". The Astronomical Journal 156 (3): 102. doi:10.3847/1538-3881/aad050. ISSN 0004-6256. Bibcode: 2018AJ....156..102S. 
  16. ↑ 16.0 16.1 16.2 16.3 16.4 Anders, F. et al. (1 August 2019). "Photo-astrometric distances, extinctions, and astrophysical parameters for Gaia DR2 stars brighter than G = 18". Astronomy and Astrophysics 628: A94. doi:10.1051/0004-6361/201935765. ISSN 0004-6361. Bibcode: 2019A&A...628A..94A. 
  17. ↑ Tezlaff, L. S.; Neuhäuser, R.; Hohle, N. N. (January 2011). "A catalogue of young runaway Hipparcos stars within 3 kpc from the Sun". Monthly Notices of the Royal Astronomical Society 410 (1): 190–200. doi:10.1111/j.1365-2966.2010.17434.x. Bibcode: 2011MNRAS.410..190T. 
  18. ↑ Stassun, Keivan G. et al. (2019-10-01). "The Revised TESS Input Catalog and Candidate Target List". The Astronomical Journal 158 (4): 138. doi:10.3847/1538-3881/ab3467. ISSN 0004-6256. Bibcode: 2019AJ....158..138S. 
  19. ↑ 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.
  20. ↑ Mason, Brian D.; Wycoff, Gary L.; Hartkopf, William I.; Douglass, Geoffrey G.; Worley, Charles E. (2001). "The 2001 US Naval Observatory Double Star CD-ROM. I. The Washington Double Star Catalog". The Astronomical Journal 122 (6): 3466. doi:10.1086/323920. Bibcode: 2001AJ....122.3466M. 
  21. ↑ Shaw, J. S.; Fraquelli, D. A.; Martins, D. H.; Andrew, S. B. (1983). "HR 8768 - an Ultra Short Period Variable?". Information Bulletin on Variable Stars 2288: 1. Bibcode: 1983IBVS.2288....1S. 



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