Chi Aquarii
Star in the constellation Aquarius
From Wikipedia, the free encyclopedia
Chi Aquarii is a star in the equatorial constellation of Aquarius. Its name is a Bayer designation that is Latinized from χ Aquarii, and abbreviated Chi Aqr or χ Aqr. The distance to this star, based upon parallax measurements with a 7% margin of error,[2] is 530 light-years (160 parsecs). It is visible to the naked eye with an apparent visual magnitude of about 5.[3]
  | |
| Observation data Epoch J2000 Equinox ICRS | |
|---|---|
| Constellation | Aquarius[1] |
| Right ascension | 23h 16m 50.939s[2] |
| Declination | −07° 43′ 35.40″[2] |
| Apparent magnitude (V) | 4.75–5.10[3] |
| Characteristics | |
| Evolutionary stage | AGB[4] |
| Spectral type | M3 III[5] |
| U−B color index | +1.60[6] |
| B−V color index | +1.60[6] |
| Variable type | SRb?[3] |
| Astrometry | |
| Radial velocity (Rv) | −13.72±0.86[7] km/s |
| Proper motion (μ) | RA: −17.721 mas/yr[2] Dec.: −13.676 mas/yr[2] |
| Parallax (π) | 6.1612±0.2060 mas[2] |
| Distance | 530 ± 20 ly (162 ± 5 pc) |
| Absolute magnitude (MV) | −1.43[1] |
| Details | |
| Radius | 142[8] R☉ |
| Luminosity | 2,598[8] L☉ |
| Surface gravity (log g) | 0.128[8] cgs |
| Temperature | 3,456[8] K |
| Other designations | |
| χ Aqr, 92 Aquarii, AAVSO 2311-08, BD−08 6076, GC 32401, HD 219576, HIP 114939, HR 8850, SAO 146612, PPM 207366[9] | |
| Database references | |
| SIMBAD | data |
The variability of the brightness of Chi Aquarii was announced by Joel Stebbins and Charles Morse Huffer in 1928, based on observations made at Washburn Observatory.[11] It is classified as a semi-regular variable star and its brightness varies by an amplitude of 0.0636 in magnitude.[12] The identified pulsation periods are 32.3, 38.5, and 44.9 days.[13]
This is an aging red giant star with a spectral classification of M3 III.[5] After the supply of hydrogen at its core was exhausted, it evolved off the main sequence, expanding to about 142 times the radius of the Sun.[8] The star is radiating 2,598 times the luminosity of the Sun from its enlarged photosphere at an effective temperature of 3,456 K.[8]