GG Lupi
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  | |
| Observation data Epoch J2000 Equinox J2000 | |
|---|---|
| Constellation | Lupus |
| Right ascension | 15h 18m 56.3747s[1] |
| Declination | −40° 47′ 17.597″[1] |
| Apparent magnitude (V) | 5.58–6.11[2] |
| Characteristics | |
| Spectral type | B7V (primary) B9V (secondary) |
| U−B color index | −0.46[3] |
| B−V color index | −0.099[3] |
| Variable type | Algol[2] |
| Astrometry | |
| Radial velocity (Rv) | +4.0±1.0[3] km/s |
| Proper motion (μ) | RA: −19.219[1] mas/yr Dec.: −21.791[1] mas/yr |
| Parallax (π) | 6.6639±0.0894 mas[1] |
| Distance | 489 ± 7 ly (150 ± 2 pc) |
| Absolute magnitude (MV) | −0.53[4] |
| Orbit[3] | |
| Period (P) | 1.8495927 d |
| Semi-major axis (a) | 12.01 AU |
| Eccentricity (e) | 0.15 |
| Inclination (i) | 87.5° |
| Details | |
| Primary | |
| Mass | 4.16±0.12[3] M☉ |
| Radius | 2.42±0.05[3] R☉ |
| Surface gravity (log g) | 4.28[3] cgs |
| Temperature | 13,000[3] K |
| Rotational velocity (v sin i) | 97±8[5] km/s |
| Secondary | |
| Mass | 2.64±0.12[3] M☉ |
| Radius | 1.79±0.04[3] R☉ |
| Surface gravity (log g) | 4.30[3] cgs |
| Temperature | 10,600[3] K |
| Rotational velocity (v sin i) | 61±5[5] km/s |
| Age | 20[6] Myr |
| Other designations | |
| HD 135876, HIP 74950, HR 5687, SAO 225647, 2MASS J15185637-4047176[7] | |
| Database references | |
| SIMBAD | data |
GG Lupi is an eclipsing binary star in the southern constellation of Lupus. Most of the time it is a magnitude 5.6 object, making it faintly visible to the naked eye, but during the primary eclipse its brightness falls to 6.1.[2] GG Lupi is located one half-degree (one full moon diameter) west of the third-magnitude star Delta Lupi.
This star was found to be a spectroscopic binary in 1930,[9] and its eclipses were detected in observations during 1964.[10] Its location in the sky, distance (~490 light-years)[1] and proper motion make it a likely member of the Scorpius–Centaurus association within the Gould's Belt star-formation region.[3] The two stars comprising this binary are both very young main-sequence stars of spectral type B. They are estimated to be about 20 million years old, placing them near the zero-age main sequence.[6] Their orbit is somewhat eccentric (e=0.15) and the period of apsidal precession is 102 years.[11]
