Gamma Arietis (γ Arietis, abbreviated Gamma Ari, γ Ari) is a

binary star A binary star 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 using a telescope as separate stars, in wh ...

(possibly trinary) in the northern

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 ...

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

. The two components are designated γ¹ Arietis or Gamma Arietis B and γ² Arietis or Gamma Arietis A (formally named Mesarthim , the traditional name for the Gamma Arietis system). γ¹ Arietis may itself be a

spectroscopic binary A binary star is a system of two star, stars that are gravity, 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 using a telescope as separa ...

with a low mass companion. The combined

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 the stars is 3.86, which is readily visible to the naked eye and makes this the fourth-brightest member of Aries. Based upon

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 ...

measurements obtained during 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 ...

mission, the distance to Gamma Arietis 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 ...

is approximately .

Properties

The

double star In observational astronomy, a double star or visual double is a pair of stars that appear close to each other as viewed from Earth, especially with the aid of optical telescopes. This occurs because the pair either forms a binary star (i.e. a bi ...

nature of this system was discovered by

Robert Hooke Robert Hooke FRS (; 18 July 16353 March 1703) was an English polymath active as a scientist, natural philosopher and architect, who is credited to be one of two scientists to discover microorganisms in 1665 using a compound microscope that ...

in 1664. The two components have an

angular separation Angular distance \theta (also known as angular separation, apparent distance, or apparent separation) is the angle between the two sightlines, or between two point objects as viewed from an observer. Angular distance appears in mathematics (in pa ...

of 7.606

arcsecond A minute of arc, arcminute (arcmin), arc minute, or minute arc, denoted by the symbol , is a unit of angular measurement equal to of one degree. Since one degree is of a turn (or complete rotation), one minute of arc is of a turn. The na ...

s, which can be resolved with a small

telescope A telescope is a device used to observe distant objects by their emission, absorption, or reflection of electromagnetic radiation. Originally meaning only an optical instrument using lenses, curved mirrors, or a combination of both to observe ...

. The

orbital period The orbital period (also revolution period) is the amount of time a given astronomical object takes to complete one orbit around another object. In astronomy, it usually applies to planets or asteroids orbiting the Sun, moons orbiting planets ...

of the pair is greater than 5000 years. GammaAriLightCurve

The brighter component, γ² Arietis, is an α² CVn 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 ...

, a type of star with a strong magnetic field and enhanced spectral lines of some metals, with high

chromospheric A chromosphere ("sphere of color") is the second layer of a star's atmosphere, located above the photosphere and below the solar transition region and corona. The term usually refers to the Sun's chromosphere, but not exclusively. In the S ...

activity causing brightness changes as the star rotates. Its brightness varies by 0.04 magnitudes with a period of 2.61 days. It is also an

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 ...

, a type of chemically peculiar star with enhanced lines of many metals. The spectral class has been given as A2IVpSiSrCr, noting the particular strength of lines of silicon, strontium, and chromium, although other lines such as Europium, mercury, and manganese are also stronger than a normal star. This spectral type suggests that the star is an A2-class

subgiant A subgiant is a star that is brighter than a normal main-sequence star of the same spectral class, but not as bright as giant stars. The term subgiant is applied both to a particular spectral luminosity class and to a stage in the evolution of ...

. One study identified a low-mass companion to γ² Arietis, a probable

red dwarf ''Red Dwarf'' is a British science fiction comedy franchise created by Rob Grant and Doug Naylor, which primarily consists of a television sitcom that aired on BBC Two between 1988 and 1999, and on Dave since 2009, gaining a cult following. T ...

in a close orbit. The marginally fainter of the two visible stars, γ¹ Arietis, is a Lambda Boötis ( chemically peculiar) 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 A0Vnp and a magnitude of 4.64. Lambda Boötis stars are identified based on unusually low abundances 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 in their spectra. The spectral class has also been given as A0IV-V(n)kB8, indicating that

calcium K line In physics and optics, the Fraunhofer lines are a set of spectral absorption lines named after the German physicist Joseph von Fraunhofer (1787–1826). The lines were originally observed as dark features (absorption lines) in the optical spectru ...

s in its spectrum are more typical of a B8 star. Older studies often classified it as B9 or B9.5 with a luminosity class of IV or V, indicating either a

main sequence In astronomy, the main sequence is a continuous and distinctive band of stars that appears on plots of stellar color versus brightness. These color-magnitude plots are known as Hertzsprung–Russell diagrams after their co-developers, Ejnar Her ...

or subgiant. Both of the visible stars have mass of about , luminosities of about ,

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 ...

s of about , and radii of about . Their age is about 34 million years.

Nomenclature

''γ Arietis'' ( Latinised to ''Gamma Arietis'') is the system's

Bayer designation A Bayer designation is a stellar designation in which a specific star is identified by a Greek or Latin letter followed by the genitive form of its parent constellation's Latin name. The original list of Bayer designations contained 1,564 stars. ...

; γ¹ and γ² Arietis those of its two components. The designation of the two components as ''Gamma Arietis A'' and ''B'' derive from the convention used by the Washington Multiplicity Catalog (WMC) for

multiple star system A star system or stellar system is a small number of stars that orbit each other, bound by gravitational attraction. A large group of stars bound by gravitation is generally called a '' star cluster'' or '' galaxy'', although, broadly speaki ...

s, and adopted by 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). Gamma Arietis has been called "the First Star in Aries" as having been at one time the nearest visible star to the equinoctial point. It bore the traditional name ''Mesarthim''. Originally it had shared the name

Sheratan Beta Arietis (β Arietis, abbreviated Beta Ari, β Ari), officially named Sheratan , is a star system and the second-brightest star in the constellation of Aries, marking the ram's second horn. Nomenclature ''Beta Arietis'' is the sta ...

with Beta Arietis. However, this got corrupted to "Sartai" in medieval manuscripts, which Bayer erroneously explained as being the Hebrew grammatical term "servants", and later scholars picked up on this term. 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 catalogue and standardize proper names for stars. The WGSN decided to attribute proper names to individual stars rather than entire multiple systems. It approved the name ''Mesarthim'' for the component ''γ² Arietis'' on 21 August 2016 and it is now so entered in the IAU Catalog of 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 ''

Bond Bond or bonds may refer to: Common meanings * Bond (finance), a type of debt security * Bail bond, a commercial third-party guarantor of surety bonds in the United States * Chemical bond, the attraction of atoms, ions or molecules to form chemica ...

(asterism)'', refers to an asterism consisting of Gamma,

Beta Beta (, ; uppercase , lowercase , or cursive ; grc, βῆτα, bē̂ta or ell, βήτα, víta) is the second letter of the Greek alphabet. In the system of Greek numerals, it has a value of 2. In Modern Greek, it represents the voiced labiod ...

and

Alpha Arietis Hamal , designation Alpha Arietis (α Arietis, abbreviated Alpha Ari, α Ari), is the brightest star in the northern zodiacal constellation of Aries. With an apparent visual magnitude of 2.0, it is the mean 50th-brightest star in th ...

. 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 often a ...

for Gamma Arietis itself is (, en, the Second Star of Bond).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. In

Hindu astrology Jyotisha or Jyotishya (from Sanskrit ', from ' “light, heavenly body" and ''ish'' - from Isvara or God) is the traditional Hindu system of astrology, also known as Hindu astrology, Indian astrology and more recently Vedic astrology. It is one ...

, Gamma Arietis and Beta Arietis (Sheratan) are

Ashvins The Ashvins ( sa, अश्विन्, Aśvin, horse possessors), also known as Ashwini Kumara and Asvinau,, §1.42. are Hindu deities, Hindu twin gods associated with medicine, health, dawn and sciences. In the ''Rigveda'', they are described ...

, the twin

Rigvedic deities Rigvedic deities are deities mentioned in the sacred texts of Rigveda, the principal text of the historical Vedic religion of the Vedic period (1500–500 BCE). There are 1,028 hymns (sūkta) in the Rigveda. Most of these hymns are dedicated to s ...

who act as doctors of the divine of the worl
(Richard H Allen)

References

External links

HR 545

HR 546

Image Gamma Arietis

Image Gamma2 Arietis
{{DEFAULTSORT:Gamma Arietis 011502 Binary stars 008832 Aries (constellation) Arietis, Gamma Alpha2 Canum Venaticorum variables A-type main-sequence stars

Mesarthim Gamma Arietis (γ Arietis, abbreviated Gamma Ari, γ Ari) is a binary star (possibly trinary) in the northern constellation of Aries. The two components are designated γ1 Arietis or Gamma Arietis B and γ2 Arietis or Gamma Arie ...

Arietis, 05 0545 6 A-type subgiants Durchmusterung objects Lambda Boötis stars