52 Sagittarii
Binary star system in the constellation Sagittarius
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52 Sagittarii is a binary star[12] system in the southern constellation of Sagittarius. It has the Bayer designation h2 Sagittarii, while 52 Sagittarii is the Flamsteed designation. This system is visible to the naked eye as a faint, blue-white hued point of light with an apparent visual magnitude of 4.59.[2] It is located approximately 190 light years away based on parallax,[1] but is drifting closer with a radial velocity of −19 km/s.[6]
 | |
| Observation data Epoch J2000 Equinox ICRS | |
|---|---|
| Constellation | Sagittarius |
| Right ascension | 19h 36m 42.43288s[1] |
| Declination | −24° 53′ 01.0288″[1] |
| Apparent magnitude (V) | 4.59[2] + 9.2 |
| Characteristics | |
| Evolutionary stage | main sequence[3] |
| Spectral type | B8/9V[4] + K2–4V |
| U−B color index | −0.15[5] |
| B−V color index | −0.06[5] |
| Astrometry | |
| Radial velocity (Rv) | −19.00[6] km/s |
| Proper motion (μ) | RA: +68.30[1] mas/yr Dec.: −21.51[1] mas/yr |
| Parallax (π) | 17.20±0.23 mas[1] |
| Distance | 190 ± 3 ly (58.1 ± 0.8 pc) |
| Absolute magnitude (MV) | 0.77[2] |
| Details | |
| 52 Sgr A | |
| Mass | 3.0±0.1[7] M☉ |
| Radius | 2.1[8] R☉ |
| Luminosity | 60.5+1.9 −1.8[3] L☉ |
| Surface gravity (log g) | 4.19[9] cgs |
| Temperature | 10,592+74 −72[3] K |
| Metallicity [Fe/H] | 0.00[10] dex |
| Rotational velocity (v sin i) | 48[3] km/s |
| Age | 57.3±11.7[7] Myr |
| Other designations | |
| h2 Sgr, 52 Sgr, NSV 12191, CD−25°14184, GC 27089, HD 184707, HIP 96465, HR 7440, SAO 188337, CCDM J19367-2453AB, WDS J19367-2453AB, GSC 06893-02132[11] | |
| Database references | |
| SIMBAD | data |
The primary component is a B-type main-sequence star with a stellar classification of B8/9V.[4] Garrison and Gray (1994) assigned it a class of kB8 hB9 HeA0 Va (Sr Fe II),[13] displaying the calcium K line of a B8 class star, the hydrogen lines of a B9 star, and the helium lines of an A0 star, along with overabundances of strontium and iron. It is around 57[7] million years old with three[7] times the mass of the Sun and about 2.1[8] times the Sun's radius. It is radiating 60.5[3] times the luminosity of the Sun from its photosphere at an effective temperature of 10,592 K.[3] The star is spinning with a projected rotational velocity of 48 km/s.[3]
52 Sagittarii has one companion at an angular separation of 2.4″. This object is magnitude 9.2 with a spectral class in the K2V-K4V range, and is believed to be the source of X-ray emissions from the system.[14][15]