Upsilon Serpentis, Latinized from υ Serpentis, is a star in the Serpens Caput section of 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 ...

. Based upon an annual parallax shift of 13.04 mas as seen from Earth, it is located around 250 light years from the

Sun The Sun is the star at the center of the Solar System. It is a nearly perfect ball of hot plasma, heated to incandescence by nuclear fusion reactions in its core. The Sun radiates this energy mainly as light, ultraviolet, and infrared radi ...

. The star is bright enough to be faintly visible to the naked eye, having 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 +5.70. It is a member of the Hyades group, a stream of stars that share a similar trajectory to the Hyades cluster. This is an

A-type main sequence star An A-type main-sequence star (A V) or A dwarf star is a main-sequence (hydrogen-burning) star of spectral type A and luminosity class V (five). These stars have spectra defined by strong hydrogen Balmer absorption lines. They measure between 1 ...

with a stellar classification of A3 V. It has an estimated 2.9 times the mass of the Sun and around 2.2 times the Sun's radius. With an age of 403 million years, it has a high rate of spin with a

projected rotational velocity Stellar rotation is the angular motion of a star about its axis. The rate of rotation can be measured from the spectrum of the star, or by timing the movements of active features on the surface. The rotation of a star produces an equatorial bulg ...

of 133 km/s. It is radiating 23 times the

solar luminosity The solar luminosity (), is a unit of radiant flux ( power emitted in the form of photons) conventionally used by astronomers to measure the luminosity of stars, galaxies and other celestial objects in terms of the output of the Sun. One nominal ...

from its photosphere at an effective temperature of 8,917 K. Upsilon Serpentis is a suspected astrometric binary, which means an undetected companion is perturbing the motion of the visible star. An X-ray emission has been detected from this system with a luminosity of . This may be coming from the companion, since A-type stars are not expected to emit X-rays.

References

{{DEFAULTSORT:Upsilon Serpentis A-type main-sequence stars Astrometric binaries Hyades Stream Serpens Serpentis, Upsilon Durchmusterung objects Serpentis, 31 141187 077336 5870