KX Andromedae

KX Andromedae

A light curve for KX Andromedae, plotted from Hipparcos data,[1] folded with the period published by Koen and Eyer (2002)[2]
Observation data
Epoch J2000      Equinox J2000
Constellation Andromeda
Right ascension 23h 07m 06.2120s[3]
Declination +50° 11′ 32.4891″[3]
Apparent magnitude (V) 6.88 – 7.28 variable[4]
Characteristics
Spectral type B3pe+K1III[5]
Apparent magnitude (U) 6.79[6]
Apparent magnitude (B) 7.25[6]
Apparent magnitude (V) 6.92[6]
Apparent magnitude (G) 6.8227[3]
Apparent magnitude (J) 5.845[7]
Apparent magnitude (H) 5.33[6]
Apparent magnitude (K) 5.19[6]
Variable type Be star
Astrometry
Radial velocity (Rv)−7.8±0.9[8] km/s
Proper motion (μ) RA: 1.697±0.057 [3] mas/yr
Dec.: −0.788±0.048[3] mas/yr
Parallax (π)1.2444 ± 0.0328 mas[3]
Distance2,620 ± 70 ly
(800 ± 20 pc)
Orbit[9]
Period (P)38.919 days
Eccentricity (e)0±0.03
Inclination (i)50±5°
Periastron epoch (T)HJD 2423220.25±0.09
Semi-amplitude (K2)
(secondary)		86.2±0.8 km/s
Details
Primary
Mass9.0±0.1[10] M☉
Age22.4±3.1[10] Myr
Secondary
Radius19±4[9] R☉
Surface gravity (log g)2.0±0.5[9] cgs
Temperature5000±400[9] K
Rotational velocity (v sin i)25±5[9] km/s
Other designations
2MASS J23070621+5011324, AAVSO 2302+49, BD+49 4045, HIP 114154, HD 218393, SAO 52701, TYC 3631-1533-1
Database references
SIMBADdata

KX Andromedae (often abbreviated to KX And) is a spectroscopic binary star in the constellation Andromeda. Its apparent visual magnitude varies between 6.88 and 7.28.[4]

The primary component of the KX Andromedae system is a Be star with a spectral classification B3pe as in 2017,[4] although on historical record it has varied from B1 to B7.[11]

The secondary star is difficult to detect in the spectrum, but has been given a K1III spectral type. It is likely to be an asymptotic giant branch star that fills its Roche lobe.[9]

The system is only about 25 million years old. The pair complete a circular orbit every 38.919 days at an inclination of 50°.[9]

  1. ^ Cite error: The named reference CDS was invoked but never defined (see the help page).
  2. ^ Cite error: The named reference Koen was invoked but never defined (see the help page).
  3. ^ a b c d e f 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. Gaia DR2 record for this source at VizieR.
  4. ^ a b c Cite error: The named reference GCVS was invoked but never defined (see the help page).
  5. ^ Cite error: The named reference shenavrin was invoked but never defined (see the help page).
  6. ^ a b c d e Cite error: The named reference 11colors was invoked but never defined (see the help page).
  7. ^ Cite error: The named reference 2MASS Cat was invoked but never defined (see the help page).
  8. ^ Cite error: The named reference ncsbo was invoked but never defined (see the help page).
  9. ^ a b c d e f g Cite error: The named reference Tarasov1998 was invoked but never defined (see the help page).
  10. ^ a b Cite error: The named reference Tezlaff2011 was invoked but never defined (see the help page).
  11. ^ Koubský, P.; Harmanec, P.; Brož, M.; Kotková, L.; Yang, S.; Božić, H.; Sudar, D.; Frémat, Y.; Korčáková, D.; Votruba, V.; Škoda, P.; Šlechta, M.; Ruždjak, D. (2019), "Properties and nature of be stars", Astronomy & Astrophysics, 629: A105, arXiv:1908.02719, doi:10.1051/0004-6361/201834597, S2CID 199472856