HR 4796
HR 4796 is a binary star system in the southern constellation of Centaurus. Parallax measurements put it at a distance of 235 light-years (72 parsecs) from the Earth. The two components of this system have an angular separation of 7.7 arcseconds, which, at their estimated distance, is equivalent to a projected separation of about 560 Astronomical Units (AU), or 560 times the separation of the Earth from the Sun. The star and its ring resemble an eye, and it is sometimes known by the nickname "Sauron's Eye".
A dust ring encircles HR 4796's primary star | |
| Observation data Epoch J2000.0 Equinox J2000.0 | |
|---|---|
| Constellation | Centaurus |
| Right ascension | 12h 36m 01.0318s |
| Declination | −39° 52′ 10.2226″ |
| Apparent magnitude (V) | 5.80 |
| Characteristics | |
| Spectral type | A0 V_+ M2.5 V |
| B−V color index | +0.01 |
| Astrometry | |
| Radial velocity (Rv) | 9.4 km/s |
| Proper motion (μ) | RA: −55.653±0.181 mas/yr Dec.: −23.740±0.230 mas/yr |
| Parallax (π) | 13.9064 ± 0.1349 mas |
| Distance | 235 ± 2 ly (71.9 ± 0.7 pc) |
| Absolute magnitude (MV) | 1.61±0.11 |
| Details | |
| Component A | |
| Mass | 2.18 ± 0.10 M☉ |
| Radius | 1.68 R☉ |
| Luminosity | 23 L☉ |
| Surface gravity (log g) | 4.43 cgs |
| Temperature | 9,378 K |
| Metallicity [Fe/H] | –0.03 dex |
| Rotational velocity (v sin i) | 152 km/s |
| Age | 8 ± 2 Myr |
| Component B | |
| Mass | 0.3 M☉ |
| Other designations | |
| Database references | |
| SIMBAD | data |
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