31 Lyncis is the fourth-brightest

star A star is an astronomical object comprising a luminous spheroid of plasma (physics), plasma held together by its gravity. The List of nearest stars and brown dwarfs, nearest star to Earth is the Sun. Many other stars are visible to the naked ...

in the

constellation A constellation is an area on the celestial sphere in which a group of visible stars forms Asterism (astronomy), a perceived pattern or outline, typically representing an animal, mythological subject, or inanimate object. The origins of the e ...

Lynx A lynx is a type of wild cat. Lynx may also refer to: Astronomy * Lynx (constellation) * Lynx (Chinese astronomy) * Lynx X-ray Observatory, a NASA-funded mission concept for a next-generation X-ray space observatory Places Canada * Lynx, Ontar ...

. It has the traditional name Alsciaukat, pronounced . The orange-hued star is visible to the naked eye with a baseline apparent visual magnitude of +4.25. It is a single star located about 380

light year A light-year, alternatively spelled light year, is a large unit of length used to express astronomical distances and is equivalent to about 9.46 trillion kilometers (), or 5.88 trillion miles ().One trillion here is taken to be 1012 ...

s away from the Sun, based on

parallax Parallax is a displacement or difference in the apparent position of an object viewed along two different lines of sight and is measured by the angle or semi-angle of inclination between those two lines. Due to foreshortening, nearby objects ...

, and is moving further away with a heliocentric

radial velocity The radial velocity or line-of-sight velocity, also known as radial speed or range rate, of a target with respect to an observer is the temporal rate of change, rate of change of the distance or Slant range, range between the two points. It is e ...

of +25 km/s. This object is an aging giant star with a

stellar classification In astronomy, stellar classification is the classification of stars based on their stellar spectrum, spectral characteristics. Electromagnetic radiation from the star is analyzed by splitting it with a Prism (optics), prism or diffraction grati ...

of K4+ III. A 1993 study found that it varied in brightness by 0.05 magnitude over 25 to 30 days. On the other hand, a 2002 study of the ''

Hipparcos ''Hipparcos'' was a scientific satellite of the European Space Agency (ESA), launched in 1989 and operated until 1993. It was the first space experiment devoted to precision astrometry, the accurate measurement of the positions of celestial obj ...

'' data found a period of 3.5 days. It is classified as a semiregular variable with a brightness that ranges from 4.21 to as low as 4.27, and has the

variable star designation In astronomy, a variable star designation is a unique identifier given to variable stars. It uses a variation on the Bayer designation format, with an identifying label (as described below) preceding the Latin genitive of the name of the constell ...

BN Lyncis. 31 Lyncis is 1.3 billion years old with almost double the

mass of the Sun The solar mass () is a standard unit of mass in astronomy, equal to approximately . It is often used to indicate the masses of other stars, as well as stellar clusters, nebulae, galaxies and black holes. It is approximately equal to the mass ...

. With the supply of hydrogen at its core exhausted, the star has expanded to 53 times the Sun's radius. It is radiating around 782 times the Sun's luminosity from its swollen

photosphere The photosphere is a star's outer shell from which light is radiated. The term itself is derived from Ancient Greek roots, φῶς, φωτός/''phos, photos'' meaning "light" and σφαῖρα/''sphaira'' meaning "sphere", in reference to it ...

at an

effective temperature The effective temperature of a body such as a star or planet is the temperature of a black body that would emit the same total amount of electromagnetic radiation. Effective temperature is often used as an estimate of a body's surface temperature ...

of 3,921 K.

Nomenclature

''31 Lyncis'' is the star's Flamsteed designation. It bore the traditional names ''Alsciaukat'', from

Arabic Arabic (, ' ; , ' or ) is a Semitic languages, Semitic language spoken primarily across the Arab world.Semitic languages: an international handbook / edited by Stefan Weninger; in collaboration with Geoffrey Khan, Michael P. Streck, Janet C ...

الشوكة ''aš-šawkat'' "the thorn", and ''Mabsuthat'', from Arabic المبسوطة ''al-mabsūtah'' "the outstretched (paw)". In 2016, the

International Astronomical Union The International Astronomical Union (IAU; french: link=yes, Union astronomique internationale, UAI) is a nongovernmental organisation with the objective of advancing astronomy in all aspects, including promoting astronomical research, outreac ...

(IAU) organized a

Working Group on Star Names The International Astronomical Union (IAU) established a Working Group on Star Names (WGSN) in May 2016 to catalog and standardize proper names for stars for the international astronomical community. It operates under Division C – Education ...

(WGSN) to catalog and standardize proper names for stars. The WGSN approved the name ''Alsciaukat'' for this star on 30 June 2017 and it is now so included in the List of IAU-approved Star Names.

References

{{DEFAULTSORT:31 Lyncis Lyncis, 31 Lyncis, 31 Durchmusterung objects Lyncis, 31 070272 041075 3275 Alsciaukat Lyncis, BN