| |
| Observation data Epoch J2000 Equinox J2000 | |
|---|---|
| Constellation | Serpens |
| Right ascension | 15h46m 26.61423s[1] |
| Declination | +07° 21′ 11.0475″[1] |
| Apparent magnitude (V) | 4.43[2] |
| Characteristics | |
| Spectral type | G0 V[3] |
| U−B color index | +0.11[2] |
| B−V color index | +0.60[2] |
| Variable type | Suspected |
| Astrometry | |
| Radial velocity (Rv) | −66.4[4] km/s |
| Proper motion (μ) | RA: −224.0±0.2 mas/yr[1] Dec.: −69.8±0.3 mas/yr[1] |
| Parallax (π) | 83.92 ± 0.15 mas[1] |
| Distance | 38.87 ± 0.07 ly (11.92 ± 0.02 pc) |
| Absolute magnitude (MV) | 4.01[5] |
| Details | |
| Mass | 1.14[6] M☉ |
| Radius | 1.26±0.07[7] R☉ |
| Luminosity | 1.94[6] L☉ |
| Surface gravity (log g) | 4.09[8] cgs |
| Temperature | 6,087±174[7] K |
| Metallicity [Fe/H] | −0.03[8] dex |
| Rotational velocity (v sin i) | 3[9] km/s |
| Age | 3.8–6.7[10] Gyr |
| Other designations | |
λ Ser, 27 Serpentis, NSV 7246, BD+7°3023, HD 141004, HIP 77257, HR 5868, SAO 121186, 2MASS J15462661+0721109[3] | |
| Database references | |
| SIMBAD | data |
Lambda Serpentis, Latinized from λ Serpentis, is a star in the constellation Serpens, in its head (Serpens Caput). It has an apparent visual magnitude of 4.43,[2] making it visible to the naked eye. Based upon parallax measurements, this star lies at a distance of about 38.9 light-years (11.9 parsecs) from Earth.[1] Lambda Serpentis is moving toward the Solar System with a radial velocity of 66.4 km s−1.[4] In about 166,000 years, this system will make its closest approach of the Sun at a distance of 7.371 ± 0.258 light-years (2.260 ± 0.079 parsecs), before moving away thereafter.[11]
This star is 26% larger[7] and 14% more massive than the Sun, although it has a similar stellar classification.[1] It is shining with nearly double the Sun's luminosity and this energy is being radiated from the star's outer atmosphere at an effective temperature of 6,087 K.[7] A periodicity of 1837 days (5.03 years) was suspected by Morbey & Griffith (1987),[12] but it is probably bound to stellar activity. However, McDonald Observatory team has set limits to the presence of one or more exoplanets[12] around Lambda Serpentis with masses between 0.16 and 2 Jupiter masses and average separations spanning between 0.05 and 5.2 Astronomical Units.
In 2020, a candidate planet was detected orbiting Lambda Serpentis (HD 141004). With a minimum mass of 0.043 MJ (13.6 ME) and an orbital period of 15 days, this would most likely be a hot Neptune.[13] The discovery of planet was confirmed in 2021.[14]
| Companion (in order from star) |
Mass | Semimajor axis (AU) |
Orbital period (days) |
Eccentricity | Inclination | Radius |
|---|---|---|---|---|---|---|
| b | ≥ 0.0428+0.0047 −0.0045 MJ |
0.1238±0.002 | 15.5083+0.0016 −0.0018 |
0.16+0.11 −0.10 |
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{{citation}}: CS1 maint: multiple names: authors list (link)
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