Chi Serpentis (χ Ser, χ Serpentis) is a solitary star in the Serpens Caput section of the equatorial 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 14.84 mas as seen from Earth, it is located around 222 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 +5.30. In 1966 it was listed as a suspected spectroscopic binary, but it is believed to be single. This is a

chemically peculiar star In astrophysics, chemically peculiar stars (CP stars) are stars with distinctly unusual metal abundances, at least in their surface layers. Classification Chemically peculiar stars are common among hot main-sequence (hydrogen-burning) stars. Thes ...

Ap star Ap and Bp stars are chemically peculiar stars (hence the "p") of spectral types A and B which show overabundances of some metals, such as strontium, chromium and europium. In addition, larger overabundances are often seen in praseodymium and neo ...

with a stellar classification of , indicating the

spectrum A spectrum (plural ''spectra'' or ''spectrums'') is a condition that is not limited to a specific set of values but can vary, without gaps, across a continuum. The word was first used scientifically in optics to describe the rainbow of colors ...

shows abnormal excesses of manganese and europium. The star has 2.11 times the mass of the Sun and about 1.9 times the Sun's radius. It is radiating 26 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 9,557 K. At the age of 212 million years, it is spinning with a rotation period of 1.6 days. Chi Serpentis is classified as an Alpha2 Canum Venaticorum type

variable star A variable star is a star whose brightness as seen from Earth (its apparent magnitude) changes with time. This variation may be caused by a change in emitted light or by something partly blocking the light, so variable stars are classified as e ...

, and its magnitude varies by 0.03 with a period of 1.5948 days. The pattern of variation in the spectrum suggest there are regions of enhanced strontium, chromium, iron, titanium, and magnesium on the surface of the star. The averaged quadratic field strength of the surface magnetic field is .

References

{{DEFAULTSORT:Chi Serpentis A-type main-sequence stars Alpha2 Canum Venaticorum variables Serpens Serpentis, Chi Serpentis, 20 140160 076866 5843 Durchmusterung objects