Tau Pegasi (τ Pegasi, abbreviated Tau Peg, τ Peg), formally named Salm , is a

magnitude Magnitude may refer to: Mathematics *Euclidean vector, a quantity defined by both its magnitude and its direction *Magnitude (mathematics), the relative size of an object *Norm (mathematics), a term for the size or length of a vector *Order of ...

4.6 star 162 light years away in the constellation of Pegasus. With about twice the mass of the Sun and thirty times as luminous, tt is a δ Scuti variable star with its brightness changing by a few hundredths of a magnitude over about an hour.

Nomenclature

''τ Pegasi'' ( Latinised to ''Tau Pegasi'') is the star's Bayer designation. The star bore the traditional names ''Salm'', ''Kerb'' (or ''El Khereb'') and ''Markab'' (often spelled ''Markeb''), a name shared with Alpha Pegasi, k Puppis and

Kappa Velorum Kappa Velorum (κ Velorum, abbreviated Kappa Vel, κ Vel; proper name Markeb ) is a binary star system in the southern constellation of Vela. The two components are designated Kappa Velorum A and B. From parallax measurements, this syst ...

. In 2016, the 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 ''Salm'' (a

homophone A homophone () is a word that is pronounced the same (to varying extent) as another word but differs in meaning. A ''homophone'' may also differ in spelling. The two words may be spelled the same, for example ''rose'' (flower) and ''rose'' (p ...

with the planet Samh) for this star and ''Markeb'' for the component Kappa Velorum A, both on 5 September 2017. ''Markab'' had previously been approved for Alpha Pegasi on 30 June 2016. All three are now so included in the List of IAU-approved Star Names. In

Chinese Chinese can refer to: * Something related to China * Chinese people, people of Chinese nationality, citizenship, and/or ethnicity **''Zhonghua minzu'', the supra-ethnic concept of the Chinese nation ** List of ethnic groups in China, people of ...

, (), meaning '' Resting Palace'', refers to an asterism consisting of Tau Pegasi,

Lambda Pegasi Lambda Pegasi (λ Peg, λ Pegasi) is a fourth-magnitude star in the constellation Pegasus. λ Pegasi is a yellow giant with stellar classification G8II-III. With a mass of and radius that is , the star boasts a bolometric luminosi ...

Mu Pegasi Mu Pegasi or μ Pegasi, formally named Sadalbari (), is a star in the northern constellation of Pegasus. The apparent visual magnitude of this star is 3.5, which is bright enough to be seen with the naked eye even on a moonlit night. ...

, Omicron Pegasi,

Eta Pegasi Eta Pegasi or η Pegasi, formally named Matar , is a binary star in the constellation of Pegasus. The apparent visual magnitude of this star is +2.95, making it the fifth-brightest member of Pegasus. Based upon parallax measurements ...

and Nu Pegasi. Consequently, the

Chinese name Chinese names or Chinese personal names are names used by individuals from Greater China and other parts of the Chinese-speaking world throughout East and Southeast Asia (ESEA). In addition, many names used in Japan, Korea and Vietnam are ofte ...

for Tau Pegasi itself is (), "the Fifth Star of Resting Palace".香港太空館 - 研究資源 - 亮星中英對照表
, Hong Kong Space Museum. Accessed on line November 23, 2010.

Properties

Tau Pegasi belongs to

spectral class In astronomy, stellar classification is the classification of stars based on their spectral characteristics. Electromagnetic radiation from the star is analyzed by splitting it with a prism or diffraction grating into a spectrum exhibiting the ...

A5 Vp, making it 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 ...

. It is a type of

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 ...

with unusually weak

spectral line A spectral line is a dark or bright line in an otherwise uniform and continuous spectrum, resulting from emission or absorption of light in a narrow frequency range, compared with the nearby frequencies. Spectral lines are often used to iden ...

s of

iron peak The iron peak is a local maximum in the vicinity of Fe ( Cr, Mn, Fe, Co and Ni) on the graph of the abundances of the chemical elements. For elements lighter than iron on the periodic table, nuclear fusion releases energy. For iron, and f ...

elements, a class known as λ Boötis stars. Tau Pegasi is a multiperiodic

Delta Scuti variable A Delta Scuti variable (sometimes termed dwarf cepheid when the V-band amplitude is larger than 0.3 mag.) is a subclass of young pulsating star. These variables as well as classical cepheids are important standard candles and have been used to es ...

, with reported pulsation periods ranging from 0.94 to 1.30 hours. It is rotating rapidly 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 150 km/s. Tau Pegasi is radiating nearly 30 times the

luminosity of the Sun 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 outer atmosphere at an effective temperature of 7,762 K.

References

{{DEFAULTSORT:Tau Pegasi Pegasi, Tau Pegasus (constellation) A-type main-sequence stars

Salm Salm may refer to People * Constance de Salm (1767–1845), poet and miscellaneous writer; through her second marriage, she became Princess of Salm-Dyck * Salm ibn Ziyad, an Umayyad governor of Khurasan and Sijistan * House of Salm, a European ...

Pegasi, 62 115250 8880 220061 BD+22 4810 Delta Scuti variables Ap stars