| |
| Observation data Epoch J2000 Equinox J2000 | |
|---|---|
| Constellation | Andromeda |
| Right ascension | 23h17m 56.011185s[2] |
| Declination | +45° 29′ 20.1197″[2] |
| Apparent magnitude (V) | 6.48[3] |
| Characteristics | |
| Spectral type | A0 Vp SiSr[4] or B9p SI[5] |
| B−V color index | −0.037±0.006[3] |
| Variable type | α2 CVn |
| Astrometry | |
| Radial velocity (Rv) | −0.30±4.10[3] km/s |
| Proper motion (μ) | RA: +24.740[2] mas/yr Dec.: −11.038[2] mas/yr |
| Parallax (π) | 5.4200 ± 0.0572 mas[2] |
| Distance | 602 ± 6 ly (185 ± 2 pc) |
| Absolute magnitude (MV) | 0.58[6] |
| Orbit[7] | |
| Period (P) | 48.304±0.007 d |
| Eccentricity (e) | 0.50±0.05 |
| Periastron epoch (T) | 2443720.11±0.64 JD |
| Argument of periastron (ω) (secondary) | 49.8±6.0° |
| Semi-amplitude (K1) (primary) | 25.7±2.0 km/s |
| Details | |
| Mass | 3.25[8] M☉ |
| Radius | 2.7[9] R☉ |
| Luminosity | 91.06[3] L☉ |
| Surface gravity (log g) | 3.81[10] cgs |
| Temperature | 11,444[10] K |
| Rotation | 1.62 d[11] |
| Rotational velocity (v sin i) | 65[12] km/s |
| Age | 284[6] Myr |
| Other designations | |
AG+45° 2124, BD+44° 4373, HD 219749, HIP 115036, HR 8861, SAO 52876, PPM 64037, TYC 3636-2562-1, GSC 03636-02562, 2MASS J23175600+4529201[13] | |
| Database references | |
| SIMBAD | data |
ET Andromedae is a binary star system star in the northern constellation of Andromeda.[14] It has an apparent visual magnitude of 6.48,[3] placing it at the nominal limit for visibility with the naked eye. The distance to this system can be estimated from its annual parallax shiftof5.42 mas,[2] which yields a value of 602 light years.
Variations in the radial velocity of this star suggest it is a single-lined spectroscopic binary system. This yields orbital elements with a period of 48.3 days and an eccentricity of 0.50. The a sin i value for the primary is 14.8 Gm (0.099 AU), where a is the semimajor axis and i is the (unknown) orbital inclination.[7]
The visible component is a well-studied magnetic chemically peculiar star[15] with a stellar classificationofA0 Vp SiSr.[4] The SiSr notation indicates unusual abundances of silicon and strontium in the spectrum. It has a magnetic field with an average surface value of 3.2 kT.[16] The abundance of silicon varies depending on the viewing angle.[15] The star is an Alpha2 Canum Venaticorum variable with a period of 1.618875 days.[17]
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