| |
| Observation data Epoch J2000 Equinox J2000 | |
|---|---|
| Constellation | Crux |
| Right ascension | 12h41m 56.56824s[2] |
| Declination | −59° 41′ 08.9564″[2] |
| Apparent magnitude (V) | 4.91[3] |
| Characteristics | |
| Spectral type | B5III[4] or B6IV[5] |
| U−B color index | −0.37[6] |
| B−V color index | −0.044±0.03[3] |
| Variable type | γ Cas?[7] |
| Astrometry | |
| Radial velocity (Rv) | +12.5±2.8[3] km/s |
| Proper motion (μ) | RA: -23.987[2] mas/yr Dec.: -4.110[2] mas/yr |
| Parallax (π) | 4.2068 ± 0.1651 mas[2] |
| Distance | 780 ± 30 ly (238 ± 9 pc) |
| Absolute magnitude (MV) | −2.41[3] |
| Details | |
| Mass | 5.30±0.27[8] M☉ |
| Radius | 11.20±0.22[9] R☉ |
| Luminosity | 1,073[3] L☉ |
| Surface gravity (log g) | 2.90±0.03[9] cgs |
| Temperature | 10,600±106[9] K |
| Rotational velocity (v sin i) | 240[10] km/s |
| Age | 120[11][better source needed] Myr |
| Other designations | |
CH Cru, CPD−59° 4393, HD 110335, HIP 61966, HR 4823, SAO 240161, G 39 Crucis[12][13] | |
| Database references | |
| SIMBAD | data |
CH Crucis is a solitary[14] variable star in the southern constellationofCrux. It has the Gould designation 39 G. Crucis.[12] The object is visible to the naked eye as a faint, blue-white hued point of light with an apparent visual magnitude that fluctuates around 4.91.[3] The star is located approximately 780 light years distant from the Sun based on parallax,[2] and is drifting further away with a radial velocity of about +12.5 km/s.[3] It is a member of the nearby Sco OB2 association.[15]
This is a conventional shell star, which is understood to be a Be star that is being viewed edge-on.[16] Houk (1975) found a stellar classification of B5III,[4] while Hiltner et al. assigned it to B6IV;[5] suggesting it is a B-type star that is evolving off the main sequence.[8] Samus et al. (2017) have tentatively classified it as a Gamma Cassiopeiae variable that ranges in brightness from magnitude 4.88 down to 5.7.[7]
CH Crucis has 5.3[8] times the mass of the Sun and 11.2[9] times the Sun's radius. It is radiating 1,073[3] times the luminosity of the Sun from its photosphere at an effective temperature of 10,600 K.[9] It is spinning rapidly with estimates of the projected rotational velocity ranging up to 240 or 250 km/s.[16][10] This is giving the star an oblate shape with an equatorial bulge that is an estimated 18% larger than the polar radius.[10]
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