Mu Serpentis
Star in the constellation Serpens
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Mu Serpentis, Latinized from μ Serpentis, is a binary star[6] in the Serpens Caput (head) section of the equatorial constellation Serpens. It is visible to the naked eye with an apparent visual magnitude of 3.543.[2] Based upon an annual parallax shift of 19.23 mas as seen from Earth,[1] it is located around 170 light years from the Sun.
 | |
| Observation data Epoch J2000.0 Equinox J2000.0 (ICRS) | |
|---|---|
| Constellation | Serpens |
| Right ascension | 15h 49m 37.20696s[1] |
| Declination | −03° 25′ 48.7358″[1] |
| Apparent magnitude (V) | 3.543[2] |
| Characteristics | |
| Spectral type | A0 V[3] |
| U−B color index | −0.025[2] |
| B−V color index | −0.032[2] |
| Astrometry | |
| Radial velocity (Rv) | −9.4±2.7[4] km/s |
| Proper motion (μ) | RA: −100.28[1] mas/yr Dec.: +25.99[1] mas/yr |
| Parallax (π) | 19.23±0.38 mas[1] |
| Distance | 170 ± 3 ly (52 ± 1 pc) |
| Absolute magnitude (MV) | −0.04[5] |
| Orbit[6] | |
| Period (P) | 36±2 yr |
| Semi-major axis (a) | 0.110±0.010″ |
| Eccentricity (e) | 0.4±0.3 |
| Inclination (i) | 103±28° |
| Longitude of the node (Ω) | 296±28° |
| Periastron epoch (T) | 1988.9±1.8 |
| Argument of periastron (ω) (secondary) | 308±32° |
| Details | |
| μ Ser A | |
| Mass | 2.4 ± 0.4[6] M☉ |
| Luminosity | 92[7] L☉ |
| Temperature | 9,487[7] K |
| Rotational velocity (v sin i) | 96[8] km/s |
| μ Ser B | |
| Mass | 2.3 ± 0.4 M☉ |
| Other designations | |
| μ Ser, 32 Serpentis, BD−02°4052, FK5 585, HD 141513, HIP 77516, HR 5881, SAO 140787[9] | |
| Database references | |
| SIMBAD | data |
This is an astrometric binary for which coarse orbital elements have been determined based on interferometric observations. The pair orbit each other with a period of around 36 years and an eccentricity of roughly 0.4.[6] The primary member, component A, is a white-hued A-type main sequence star with a stellar classification of A0 V.[3] The nature of the secondary, component B, is less certain – it may be a class A or F type star of unknown luminosity class.[6]
In Chinese astronomy, Mu Serpentis is called 天乳, Pinyin: Tiānrǔ, meaning Celestial Milk, because this star is marking itself and stand alone in Celestial Milk asterism, Root mansion (see : Chinese constellation).[10]