Astronomy:AC Andromedae

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Short description: Variable star in the constellation Andromeda
AC Andromedae
ACAndLightCurve.png
A visual band light curve of AC Andromedae, from data presented by Peña et al.[1]
Observation data
Equinox J2000.0]] (ICRS)
Constellation Andromeda
Right ascension  23h 18m 02.34605s[2]
Declination +48° 46′ 58.3403″[2]
Apparent magnitude (V) 10.7 – 11.9 variable [3]
Characteristics
Spectral type F5[4]
Apparent magnitude (B) 11.48[5]
Apparent magnitude (V) 10.90[5]
Apparent magnitude (G) 10.9002[2]
Apparent magnitude (J) 9.646[6]
Apparent magnitude (H) 9.483[6]
Apparent magnitude (K) 9.345[6]
B−V color index 0.5389[5]
Variable type Peculiar[3]
Astrometry
Radial velocity (Rv)−50.0±2.8[7] km/s
Proper motion (μ) RA: −2.160±0.012 [2] mas/yr
Dec.: −2.345±0.013[2] mas/yr
Parallax (π)0.4948 ± 0.0138[2] mas
Distance6,600 ± 200 ly
(2,020 ± 60 pc)
Absolute magnitude (MV)−0.82[4]
Details
Mass3.4[2] M☉
Radius11[2] R☉
Luminosity170[2] L☉
Surface gravity (log g)2.76[8] cgs
Temperature6,315[9] K
Metallicity [Fe/H]−1.46[8] dex
Age271[2] Myr
Other designations
2MASS J23180234+4846582, BD+47 4104, HIP 115046, TYC 3644-2114-1
Database references
SIMBADdata

AC Andromedae (AC And) is a variable star in the constellation Andromeda. Its maximum apparent visual magnitude is 10.77, but can be seen fainter down to a magnitude of 11.9.

AC Andromedae was first reported to be a variable star by Paul Guthnick and Richard Prager in 1927. They noted that it varied in brightness rapidly, with no discernible period.[10][11]

The nature of AC Andromedae is still not determined. Its light curve shows clearly three radial pulsation modes, the fundamental one with a period of 0.71 days, and the first two overtones of 0.525 and 0.421 days, respectively. It is then unclear if it belongs to the class of RR Lyrae variables or to the one of Delta Scuti variables.[12][13] Another study points at AC And as an intermediate object between classical Cepheids and Delta Scuti variables.[4] The physical parameters of the star itself would be different depending on which class it belongs to.

By late 2018, the AC Andromedae was classified as rare "triple-mode" subtype of the dwarf cepheid (high-amplitude Delta Scuti variable).[14][15]

References

  1. ↑ Peña, J. H.; Peniche, R.; Hobart, M. A.; de la Cruz, C.; Gallegos, A. A. (2005). "Uvby-β Photometry of the RR Lyrae Star AC and". Revista Mexicana de Astronomía y Astrofísica 41: 461. Bibcode: 2005RMxAA..41..461P. 
  2. ↑ 2.0 2.1 2.2 2.3 2.4 2.5 2.6 2.7 2.8 2.9 Vallenari, A. et al. (2022). "Gaia Data Release 3. Summary of the content and survey properties". Astronomy & Astrophysics. doi:10.1051/0004-6361/202243940  Gaia DR3 record for this source at VizieR.
  3. ↑ 3.0 3.1 AC And, database entry, Combined General Catalog of Variable Stars (GCVS4.2, 2004 Ed.), N. N. Samus, O. V. Durlevich, et al., CDS ID II/250 Accessed on line 2018-10-17.
  4. ↑ 4.0 4.1 4.2 Fernie, J. D. (November 1994). "AC Andromedae: the missing link between δ Scuti stars and classical Cepheids?". Monthly Notices of the Royal Astronomical Society 271: L19–L20. doi:10.1093/mnras/271.1.L19. Bibcode: 1994MNRAS.271L..19F. 
  5. ↑ 5.0 5.1 5.2 Høg, E.; Fabricius, C.; Makarov, V. V.; Urban, S.; Corbin, T.; Wycoff, G.; Bastian, U.; Schwekendiek, P. et al. (2000). "The Tycho-2 catalogue of the 2.5 million brightest stars". Astronomy & Astrophysics 355: L27–L30. Bibcode: 2000A&A...355L..27H. 
  6. ↑ 6.0 6.1 6.2 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. 
  7. ↑ Gontcharov, G. A. (November 2006). "Pulkovo Compilation of Radial Velocities for 35495 Hipparcos stars in a common system". Astronomy Letters 32 (11): 759–771. doi:10.1134/S1063773706110065. Bibcode: 2006AstL...32..759G. 
  8. ↑ 8.0 8.1 Anders, F.; Khalatyan, A.; Chiappini, C.; Queiroz, A. B.; Santiago, B. X.; Jordi, C.; Girardi, L.; Brown, A. G. A. et al. (2019-08-01). "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. 
  9. ↑ Stassun, Keivan G.; Oelkers, Ryan J.; Paegert, Martin; Torres, Guillermo; Pepper, Joshua; De Lee, Nathan; Collins, Kevin; Latham, David W. 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. 
  10. ↑ Guthnick, P.; Prager, R. (November 1927). "Benennung von veränderlichen Sternen". Astronomische Nachrichten 231 (10): 161–166. doi:10.1002/asna.19272311002. Bibcode: 1927AN....231..161G. 
  11. ↑ Münch, Guido (1951). "On the Spectrum of AC Andromedae". The Astrophysical Journal 114: 546. doi:10.1086/145499. Bibcode: 1951ApJ...114..546M. 
  12. ↑ Fitch, W. S.; Szeidl, B. (February 1976). "The three radial modes and evolutionary state of AC Andromedae.". Astrophysical Journal 203: 616–624. doi:10.1086/154120. Bibcode: 1976ApJ...203..616F. 
  13. ↑ Petersen, J. O. (May 1978). "An interpretation of the unique triple mode variable AC Andromedae as an RR Lyrae type star oscillating in the first three radial over-tones.". Astronomy and Astrophysics 65: 616–624. Bibcode: 1978A&A....65..451P. 
  14. ↑ Jurcsik, Johanna; Hajdu, Gergely; Catelan, Márcio (2018). "New Galactic multi-mode Cepheids from the ASAS-SN Survey". Acta Astronomica 68 (4): 341. doi:10.32023/0001-5237/68.4.2. Bibcode: 2018AcA....68..341J. 
  15. ↑ Yang, Tao-Zhi; Sun, Xiao-Ya; Zuo, Zhao-Yu; Liu, Hai-Wen (2020). "KIC 10975348: A Double-mode or Triple-mode High-amplitude δ Scuti Star?". The Astronomical Journal 161: 27. doi:10.3847/1538-3881/abcb8b. 



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