Lambda Serpentis, Latinized from λ Serpentis, is a star in the constellation

Serpens Serpens ( grc, , , the Serpent) is a constellation in the northern celestial hemisphere. One of the 48 constellations listed by the 2nd-century astronomer Ptolemy, it remains one of the 88 modern constellations designated by the International ...

, in its head (Serpens Caput). It has an

apparent visual magnitude Apparent magnitude () is a measure of the brightness of a star or other astronomical object observed from Earth. An object's apparent magnitude depends on its intrinsic luminosity, its distance from Earth, and any extinction of the object's lig ...

of 4.43, making it visible to the naked eye. Based upon parallax measurements, this star lies at a distance of about from

Earth Earth is the third planet from the Sun and the only astronomical object known to harbor life. While large volumes of water can be found throughout the Solar System, only Earth sustains liquid surface water. About 71% of Earth's surfa ...

. 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 , before moving away thereafter. This star is 6% larger and 14% 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 5,884 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 McDonald Observatory is an astronomical observatory located near unincorporated community of Fort Davis in Jeff Davis County, Texas, United States. The facility is located on Mount Locke in the Davis Mountains of West Texas, with additional faci ...

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 The astronomical unit (symbol: au, or or AU) is a unit of length, roughly the distance from Earth to the Sun and approximately equal to or 8.3 light-minutes. The actual distance from Earth to the Sun varies by about 3% as Earth orbits ...

Planetary system

In 2020, a candidate planet was detected orbiting Lambda Serpentis (HD 141004). With a

minimum mass In astronomy, minimum mass is the lower-bound calculated mass of observed objects such as planets, stars and binary systems, nebulae, and black holes. Minimum mass is a widely cited statistic for extrasolar planets detected by the radial veloci ...

of 0.043 (13.6 ) and an orbital period of 15 days, this would most likely be a

hot Neptune A hot Neptune or Hoptune is a type of giant planet with a mass similar to that of Uranus or Neptune orbiting close to its star, normally within less than 1 AU. The first hot Neptune to be discovered with certainty was Gliese 436 b in 2007, an exo ...

. The discovery of planet was confirmed in 2021.

Planetary system

References

Further reading