KX Andromedae
Spectroscopic binary star in the constellation Andromeda / From Wikipedia, the free encyclopedia
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]
Quick Facts Observation data Epoch J2000 Equinox J2000, Constellation ...
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] |
Distance | 2,620 ± 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 | |
Mass | 9.0±0.1[10] M☉ |
Age | 22.4±3.1[10] Myr |
Secondary | |
Radius | 19±4[9] R☉ |
Surface gravity (log g) | 2.0±0.5[9] cgs |
Temperature | 5000±400[9] K |
Rotational velocity (v sin i) | 25±5[9] km/s |
Other designations | |
Database references | |
SIMBAD | data |
Close
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]