Lambda Serpentis

Lambda Serpentis

Template:Location mark Location of λ Serpentis (circled)
Observation data Epoch J2000      Equinox J2000
Constellation	Serpens
Right ascension	Template:RA
Declination	Template:DEC
Apparent magnitude (V)	4.43
Characteristics
Spectral type	G0 V
U−B Template:Engvar	+0.11
B−V Template:Engvar	+0.60
Variable type	Suspected
Astrometry
Radial velocity (Rv)	−66.4 km/s
Proper motion (μ)	RA: Template:Val mas/yr Dec.: Template:Val mas/yr
Parallax (π)	83.92±0.15 mas
Distance	Template:Rnd ± Template:Rnd ly (Template:Rnd ± Template:Rnd pc)
Absolute magnitude (MV)	4.01
Details
Mass	Template:Val Template:Solar mass
Radius	Template:Val Template:Solar radius
Luminosity	Template:Val Template:Solar luminosity
Surface gravity (log g)	4.09 cgs
Temperature	Template:Val K
Metallicity [Fe/H]	−0.03 dex
Rotation	Template:Val days
Rotational velocity (v sin i)	3 km/s
Age	Template:Val Gyr
Metallicity [Fe/H]	{{{metal_fe2}}} dex
Other designations
Template:Odlist
Database references
SIMBAD	data
Exoplanet Archive	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, making it visible to the naked eye. Based upon parallax measurements, this star lies at a distance of about Template:Convert from Earth. Lambda Serpentis is moving toward the Solar System with a radial velocity of 66.4 km s⁻¹. In about 166,000 years, this system will make its closest approach of the Sun at a distance of Template:Convert, before moving away thereafter.

This star is 36% larger and 9% more massive than the Sun, although it has a similar stellar classification. 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 5,901 K. A periodicity of 1837 days (5.03 years) was suspected by Morbey & Griffith (1987), but it is probably bound to stellar activity. However, McDonald Observatory team has set limits to the presence of one or more exoplanets around Lambda Serpentis with masses between 0.16 and 2 Jupiter masses and average separations spanning between 0.05 and 5.2 Astronomical Units.

Planetary system

In 2020, a candidate planet was detected orbiting Lambda Serpentis (HD 141004). With a minimum mass of 0.043 Template:Jupiter mass (13.6 Template:Earth mass) and an orbital period of 15 days, this would most likely be a hot Neptune. The planet was confirmed in 2021.