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15 Andromedae

Coordinates: Sky map 23h 34m 37.5s, 40° 14′ 11″
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15 Andromedae

A light curve for V340 Andromedae, plotted from TESS data[1]
Observation data
Epoch J2000.0      Equinox J2000.0
Constellation Andromeda
Right ascension 23h 34m 37.53652s[2]
Declination +40° 14′ 11.1795″[2]
Apparent magnitude (V) 5.55[3]
Characteristics
Spectral type A1 III,[4] A1 Va,[5] or kA1hA3mA0.5 Va+.[6]
U−B color index 0.08
B−V color index 0.096±0.005[3]
Variable type δ Sct[7]
Astrometry
Radial velocity (Rv)13.1±0.6[3] km/s
Proper motion (μ) RA: -18.165 mas/yr
Dec.: −46.183[2] mas/yr
Parallax (π)12.9406 ± 0.0973 mas[2]
Distance252 ± 2 ly
(77.3 ± 0.6 pc)
Absolute magnitude (MV)+1.16±0.16[8]
Details[4]
Mass2.7 M☉
Luminosity27 L☉
Surface gravity (log g)3.90±0.03[8] cgs
Temperature9,225 K
Rotational velocity (v sin i)105[8] km/s
Age130 Myr
Other designations
15 And, V340 And, BD+39° 5114, FK5 1616, HD 221756, HIP 116354, HR 8947, SAO 73346, PPM 64401[9]
Database references
SIMBADdata

15 Andromedae, abbreviated 15 And, is a single,[10] variable star[7] in the northern constellation of Andromeda. 15 Andromedae is the Flamsteed designation, while its variable star designation is V340 And.[9] Its apparent visual magnitude is 5.55,[3] which indicates it is faintly visible to the naked eye. Its estimated distance from the Earth is 252 light years, and it is moving further away with a heliocentric radial velocity of 13 km/s.[3]

Rufener and Bartholdi (1982) included the star (under the name HD 221756) in their list of 333 variable, microvariable and suspected variable stars, based on multicolor photometry performed at several observatories in the 1960s and 1970s. However they were unable to conclusively demonstrate that the star's brightness varied.[11] Proof of variability, along with a light curve and period estimate of 63 minutes, was published by Paunzen and Handler in 1996.[12] The star was given its variable star designation, V340 Andromedae, in 1997.[13]

Depending on the source, this star has been classified as a giant star with a stellar classification of A1 III,[4] an A-type main-sequence star with a class of A1 Va,[5] or a Lambda Boötis star with a class of kA1hA3mA0.5 Va+.[6] It is a Delta Scuti variable that changes in brightness by 0.03 magnitude.[7] Two variability cycles, with periods 0.0403 and 0.0449 days, have been observed, a common feature for Lambda Boötis stars.[14] The star is around 130[4] million years old and has a high rotation rate, showing a projected rotational velocity of 105 km/s.[8] It has 2.7 times the mass of the Sun and is radiating 27 times the Sun's luminosity from its photosphere at an effective temperature of 9,225 K.[4]

This system has an excess emission of infrared radiation that suggests the presence of an orbiting disk of dust at a distance of around 50 AU from the host star.[4]

References

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  1. ^ "MAST: Barbara A. Mikulski Archive for Space Telescopes". Space Telescope Science Institute. Retrieved 8 December 2021.
  2. ^ a b c d Brown, A. G. A.; et al. (Gaia collaboration) (August 2018). "Gaia Data Release 2: Summary of the contents and survey properties". Astronomy & Astrophysics. 616. A1. arXiv:1804.09365. Bibcode:2018A&A...616A...1G. doi:10.1051/0004-6361/201833051.
  3. ^ a b c d e Anderson, E.; Francis, Ch. (2012), "XHIP: An extended hipparcos compilation", Astronomy Letters, 38 (5): 331, arXiv:1108.4971, Bibcode:2012AstL...38..331A, doi:10.1134/S1063773712050015, S2CID 119257644.
  4. ^ a b c d e f Wyatt, M. C.; et al. (July 2007), "Steady State Evolution of Debris Disks around A Stars", The Astrophysical Journal, 663 (1): 365–382, arXiv:astro-ph/0703608, Bibcode:2007ApJ...663..365W, doi:10.1086/518404, S2CID 18883195
  5. ^ a b Paunzen, E.; et al. (July 2001), "A spectroscopic survey for λ Bootis stars. II. The observational data", Astronomy and Astrophysics, 373 (2): 625–632, Bibcode:2001A&A...373..625P, doi:10.1051/0004-6361:20010630.
  6. ^ a b Murphy, Simon J.; et al. (2015), "An Evaluation of the Membership Probability of 212 λ Boo Stars. I. A Catalogue", Publications of the Astronomical Society of Australia, 32: e036, arXiv:1508.03633, Bibcode:2015PASA...32...36M, doi:10.1017/pasa.2015.34, ISSN 1323-3580, S2CID 59405545.
  7. ^ a b c Samus', N. N.; Kazarovets, E. V.; Durlevich, O. V.; Kireeva, N. N.; Pastukhova, E. N. (2017), "General catalogue of variable stars: Version GCVS 5.1", Astronomy Reports, 61 (1): 80, Bibcode:2017ARep...61...80S, doi:10.1134/S1063772917010085, S2CID 125853869.
  8. ^ a b c d Paunzen, E.; et al. (November 2002), "The status of Galactic field λ Bootis stars in the post-Hipparcos era", Monthly Notices of the Royal Astronomical Society, 336 (3): 1030–1042, arXiv:astro-ph/0207488, Bibcode:2002MNRAS.336.1030P, doi:10.1046/j.1365-8711.2002.05865.x, S2CID 2389489.
  9. ^ a b "15 And". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved September 20, 2018.
  10. ^ Eggleton, P. P.; Tokovinin, A. A. (September 2008), "A catalogue of multiplicity among bright stellar systems", Monthly Notices of the Royal Astronomical Society, 389 (2): 869–879, arXiv:0806.2878, Bibcode:2008MNRAS.389..869E, doi:10.1111/j.1365-2966.2008.13596.x, S2CID 14878976.
  11. ^ Rufener, F.; Bartholdi, P. (June 1982). "List of 333 variable microvariable or suspected variable stars detected in the Geneva photometry". Astronomy and Astrophysics, Supplement Series. 48: 503–511. Bibcode:1982A&AS...48..503R. Retrieved 5 November 2024.
  12. ^ Paunzen, E.; Handler, G. (March 1996). "Pulsation of HD 83041 and HD 221756". Information Bulletin on Variable Stars. 4301. Bibcode:1996IBVS.4301....1P. Retrieved 5 November 2024.
  13. ^ Kazarovets, E. V.; Samus, N. N. (April 1997). "The 73rd Name-List of Variable Stars" (PDF). Information Bulletin on Variable Stars. 4471: 1–45. Bibcode:1997IBVS.4471....1K. Retrieved 5 November 2024.
  14. ^ Dorokhova, T. N.; et al. (March 2008), "The pulsating λ Bootis star 15 Andromedae: results from a three-site photometry campaign.", Astronomy and Astrophysics, 480 (1): 187–191, Bibcode:2008A&A...480..187D, doi:10.1051/0004-6361:20078750.
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