AC Andromedae

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]

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  5. ^ a b c Cite error: The named reference TYCHO was invoked but never defined (see the help page).
  6. ^ a b c Cite error: The named reference 2MASS Cat was invoked but never defined (see the help page).
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  8. ^ a b Cite error: The named reference starhorse was invoked but never defined (see the help page).
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  10. ^ Cite error: The named reference Guthnick1927 was invoked but never defined (see the help page).
  11. ^ Cite error: The named reference Münch1951 was invoked but never defined (see the help page).
  12. ^ Cite error: The named reference Fitch1976 was invoked but never defined (see the help page).
  13. ^ Cite error: The named reference Petersen1978 was invoked but never defined (see the help page).
  14. ^ Cite error: The named reference jurcsik2018 was invoked but never defined (see the help page).
  15. ^ Cite error: The named reference yang2020 was invoked but never defined (see the help page).