Astronomy:AC Andromedae

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Short description: Variable star in the constellation Andromeda
AC Andromedae
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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[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 also displays the Blazhko effect with a modulation period of 2.11 days.[12] It is unclear if it belongs to the class of RR Lyrae variables or to the one of Delta Scuti variables.[13][14] 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).[15][16]

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. ↑ 2.00 2.01 2.02 2.03 2.04 2.05 2.06 2.07 2.08 2.09 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. ↑ Jakate, S. M. (1978-09-01). "Photoelectric photometry of AC And." (in en). The Astrophysical Journal 224: 603. doi:10.1086/156408. ISSN 0004-637X. http://adsabs.harvard.edu/doi/10.1086/156408. 
  13. ↑ 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. 
  14. ↑ 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. 
  15. ↑ 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. 
  16. ↑ 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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