AC Andromedae

A visual band light curve of AC Andromedae, from data presented by Peña et al.[1]
Observation data
Epoch J2000      Equinox J2000
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 mas[2]
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. 1 2 3 4 5 6 7 8 9 10 Vallenari, A.; et al. (Gaia collaboration) (2023). "Gaia Data 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. S2CID 244398875. Gaia DR3 record for this source at VizieR.
  3. 1 2 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. 1 2 3 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. Bibcode:1994MNRAS.271L..19F. doi:10.1093/mnras/271.1.L19.
  5. 1 2 3 Høg, E.; Fabricius, C.; Makarov, V. V.; Urban, S.; Corbin, T.; Wycoff, G.; Bastian, U.; Schwekendiek, P.; Wicenec, A. (2000). "The Tycho-2 catalogue of the 2.5 million brightest stars". Astronomy & Astrophysics. 355: L27–L30. Bibcode:2000A&A...355L..27H.
  6. 1 2 3 Cutri, Roc M.; Skrutskie, Michael F.; Van Dyk, Schuyler D.; Beichman, Charles A.; Carpenter, John M.; Chester, Thomas; Cambresy, Laurent; Evans, Tracey E.; Fowler, John W.; Gizis, John E.; Howard, Elizabeth V.; Huchra, John P.; Jarrett, Thomas H.; Kopan, Eugene L.; Kirkpatrick, J. Davy; Light, Robert M.; Marsh, Kenneth A.; McCallon, Howard L.; Schneider, Stephen E.; Stiening, Rae; Sykes, Matthew J.; Weinberg, Martin D.; Wheaton, William A.; Wheelock, Sherry L.; Zacarias, N. (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.
  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. arXiv:1606.08053. Bibcode:2006AstL...32..759G. doi:10.1134/S1063773706110065. S2CID 119231169.
  8. 1 2 Anders, F.; Khalatyan, A.; Chiappini, C.; Queiroz, A. B.; Santiago, B. X.; Jordi, C.; Girardi, L.; Brown, A. G. A.; Matijevic, G.; Monari, G.; Cantat-Gaudin, T. (2019-08-01). "Photo-astrometric distances, extinctions, and astrophysical parameters for Gaia DR2 stars brighter than G = 18". Astronomy and Astrophysics. 628: A94. arXiv:1904.11302. Bibcode:2019A&A...628A..94A. doi:10.1051/0004-6361/201935765. ISSN 0004-6361. S2CID 131780028.
  9. ↑ Stassun, Keivan G.; Oelkers, Ryan J.; Paegert, Martin; Torres, Guillermo; Pepper, Joshua; De Lee, Nathan; Collins, Kevin; Latham, David W.; Muirhead, Philip S.; Chittidi, Jay; Rojas-Ayala, Bárbara (2019-10-01). "The Revised TESS Input Catalog and Candidate Target List". The Astronomical Journal. 158 (4): 138. arXiv:1905.10694. Bibcode:2019AJ....158..138S. doi:10.3847/1538-3881/ab3467. hdl:1721.1/124721. ISSN 0004-6256. S2CID 166227927.
  10. ↑ Guthnick, P.; Prager, R. (November 1927). "Benennung von veränderlichen Sternen". Astronomische Nachrichten. 231 (10): 161–166. Bibcode:1927AN....231..161G. doi:10.1002/asna.19272311002.
  11. ↑ Münch, Guido (1951). "On the Spectrum of AC Andromedae". The Astrophysical Journal. 114: 546. Bibcode:1951ApJ...114..546M. doi:10.1086/145499.
  12. ↑ Fitch, W. S.; Szeidl, B. (February 1976). "The three radial modes and evolutionary state of AC Andromedae". Astrophysical Journal. 203: 616–624. Bibcode:1976ApJ...203..616F. doi:10.1086/154120.
  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. arXiv:1812.01575. Bibcode:2018AcA....68..341J. doi:10.32023/0001-5237/68.4.2. S2CID 119249971.
  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. arXiv:2011.09091. doi:10.3847/1538-3881/abcb8b. S2CID 227013065.
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