Beta Arietis is a

binary star A binary star or binary star system is a system of two stars that are gravitationally bound to and in orbit around each other. Binary stars in the night sky that are seen as a single object to the naked eye are often resolved as separate stars us ...

system 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 first constellati ...

Aries Aries may refer to: *Aries (astrology), an astrological sign *Aries (constellation), a constellation in the zodiac Arts, entertainment and media * ''Aries'' (album), by Luis Miguel, 1993 * ''Aries'' (EP), by Alice Chater, 2020 * "Aries" (song), ...

, marking the ram's second horn. Its identifier is a

Bayer designation A Bayer designation is a stellar designation in which a specific star is identified by a Greek alphabet, Greek or Latin letter followed by the genitive case, genitive form of its parent constellation's Latin name. The original list of Bayer design ...

that is Latinized from β Arietis, and abbreviated Beta Ari or β Ari. It has the official name Sheratan, pronounced . This system is visible to the

naked eye Naked eye, also called bare eye or unaided eye, is the practice of engaging in visual perception unaided by a magnification, magnifying, Optical telescope#Light-gathering power, light-collecting optical instrument, such as a telescope or microsc ...

as a point of light with a combined

apparent visual magnitude Apparent magnitude () is a measure of the brightness of a star, astronomical object or other celestial objects like artificial satellites. Its value depends on its intrinsic luminosity, its distance, and any extinction of the object's light ca ...

of 2.65, making this the second-brightest star in the constellation. Located at a distance of , the pair orbit each other with a

period Period may refer to: Common uses * Period (punctuation) * Era, a length or span of time *Menstruation, commonly referred to as a "period" Arts, entertainment, and media * Period (music), a concept in musical composition * Periodic sentence (o ...

of 107 days.

Nomenclature

''Beta Arietis'' is the star's

. It also bears the

Flamsteed designation A Flamsteed designation is a combination of a number and constellation name that uniquely identifies most naked eye stars in the 88 modern constellations, modern constellations visible from southern England. They are named after John Flamsteed, au ...

''6 Arietis''. The traditional name, ''Sheratan'' (or ''Sharatan, Sheratim),'' in full ''Al Sharatan,'' is from the Arabic الشرطان ''aš-šaraţān'' "the two signs", a reference to the star having marked the northern vernal equinox together with

Gamma Arietis Gamma Arietis is a binary or possibly trinary star system in the northern constellation of Aries. Its name is a Bayer designation that is Latinized from γ Arietis, and abbreviated Gamma Ari or γ Ari. This system is called "The First ...

several thousand years ago. In 2016, the

International Astronomical Union The International Astronomical Union (IAU; , UAI) is an international non-governmental organization (INGO) with the objective of advancing astronomy in all aspects, including promoting astronomical research, outreach, education, and developmen ...

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 catalogue and standardize proper names for stars. The WGSN approved the name ''Sheratan'' for this star on August 21, 2016 and it is now so entered in the IAU Catalog of Star Names. In Chinese, (), meaning '' Bond (asterism)'', refers to an asterism consisting of β Arietis,

γ Arietis Gamma Arietis is a binary or possibly trinary star system in the northern constellation of Aries. Its name is a Bayer designation that is Latinized from γ Arietis, and abbreviated Gamma Ari or γ Ari. This system is called "The First ...

and α Arietis. Consequently, the

Chinese name Chinese may refer to: * Something related to China * Chinese people, people identified with China, through nationality, citizenship, and/or ethnicity **Han Chinese, East Asian ethnic group native to China. **'' Zhonghua minzu'', the supra-ethni ...

for β Arietis itself is (, ).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

Beta Arietis has an

of 2.65. Based on dynamical

parallax Parallax is a displacement or difference in the apparent position of an object viewed along two different sightline, lines of sight and is measured by the angle or half-angle of inclination between those two lines. Due to perspective (graphica ...

measurements, it is located at a distance of from Earth. This is a

spectroscopic binary A binary star or binary star system is a system of two stars that are gravitationally bound to and in orbit around each other. Binary stars in the night sky that are seen as a single object to the naked eye are often resolved as separate stars us ...

star system consisting of a pair of stars orbiting around each other with a separation that can not currently be resolved with a conventional telescope. However, the pair have been resolved using the

Mark III Stellar Interferometer The Mark III Stellar Interferometer was a long-baseline optical astronomical interferometer, located at the Mount Wilson Observatory, California, United States.The Mark III stellar interferometer, M. Shao et al., ''Astronomy and Astrophysics'' 193, ...

at the

Mount Wilson Observatory The Mount Wilson Observatory (MWO) is an Observatory#Astronomical observatories, astronomical observatory in Los Angeles County, California, United States. The MWO is located on Mount Wilson (California), Mount Wilson, a peak in the San Gabrie ...

. This allows the

orbital elements Orbital elements are the parameters required to uniquely identify a specific orbit. In celestial mechanics these elements are considered in two-body systems using a Kepler orbit. There are many different ways to mathematically describe the same o ...

to be computed, as well as the individual masses of the two stars. The stars complete their highly

elliptical orbit In astrodynamics or celestial mechanics, an elliptical orbit or eccentric orbit is an orbit with an orbital eccentricity, eccentricity of less than 1; this includes the special case of a circular orbit, with eccentricity equal to 0. Some or ...

every 107 days. The primary star has 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 gratin ...

of A3 V, which means it is an

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

that is generating energy through the

thermonuclear fusion Nuclear fusion is a reaction in which two or more atomic nuclei combine to form a larger nuclei, nuclei/neutron by-products. The difference in mass between the reactants and products is manifested as either the release or absorption of ener ...

of hydrogen in its core region. The NStars project gives the star a spectral type of kA4 hA5 mA5 Va under the revised MK spectral classification system. The secondary star is a

G-type main-sequence star A G-type main-sequence star (spectral type: G-V), also often, and imprecisely, called a yellow dwarf, or G star, is a main sequence, main-sequence star (luminosity class V) of stellar classification, spectral type G. Such a star has about 0.9 to ...

, with a

of G2V. It is about four magnitudes fainter than the primary; hence the energy output from the system is dominated by the primary star. In a few million years, as the primary evolves toward a

red giant A red giant is a luminous giant star of low or intermediate mass (roughly 0.3–8 solar masses ()) in a late phase of stellar evolution. The stellar atmosphere, outer atmosphere is inflated and tenuous, making the radius large and the surface t ...

, significant amounts of mass transfer to the secondary component is expected. The primary has been classified as a rapid rotator, 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 bu ...

of 73 km/s providing a lower bound on the

azimuth An azimuth (; from ) is the horizontal angle from a cardinal direction, most commonly north, in a local or observer-centric spherical coordinate system. Mathematically, the relative position vector from an observer ( origin) to a point ...

al rotational velocity along the equator. It may also be a mildly

Am star An Am star or metallic-line star is a type of chemically peculiar star of spectral type A whose spectrum has strong and often variable absorption lines of metals such as zinc Zinc is a chemical element; it has symbol Zn and atomic number 30. ...

, which is a class of stars that show a peculiar spectrum with strong

absorption lines Absorption spectroscopy is spectroscopy that involves techniques that measure the absorption of electromagnetic radiation, as a function of frequency or wavelength, due to its interaction with a sample. The sample absorbs energy, i.e., photons, ...

from various elements and deficiencies in others. In β Arietis, these absorption lines are broadened because of the

Doppler effect The Doppler effect (also Doppler shift) is the change in the frequency of a wave in relation to an observer who is moving relative to the source of the wave. The ''Doppler effect'' is named after the physicist Christian Doppler, who described ...

from the rotation, making analysis of the abundance patterns difficult. This system has been examined with the

Spitzer Space Telescope The Spitzer Space Telescope, formerly the Space Infrared Telescope Facility (SIRTF), was an infrared space telescope launched in 2003, that was deactivated when operations ended on 30 January 2020. Spitzer was the third space telescope dedicate ...

for the presence of an excess emission of infrared, which would indicate a disk of dust. However, no significant excess was detected.

Notes

References

External links

GJ 80
Catalog
Image Beta Arietis

by Professor Jim Kaler.

{{DEFAULTSORT:Beta Arietis A-type main-sequence stars G-type main-sequence stars Spectroscopic binaries Aries (constellation) Arietis, Beta 0553 Durchmusterung objects Arietis, 06 0080 011636 008903

Sheratan Beta Arietis is a binary star system in the constellation of Aries, marking the ram's second horn. Its identifier is a Bayer designation that is Latinized from β Arietis, and abbreviated Beta Ari or β Ari. It has the official name Sh ...