Gamma Ceti (γ Ceti, abbreviated Gamma Cet, γ Cet) is a triple star system in the

equatorial Equatorial may refer to something related to: *Earth's equator **the tropics, the Earth's equatorial region **tropical climate *the Celestial equator ** equatorial orbit **equatorial coordinate system ** equatorial mount, of telescopes * equatorial ...

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 ...

of Cetus. It has a combined apparent visual magnitude of 3.47. 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, this star is located at a distance of about 80

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 (24.4 parsecs) from the Sun. The three components are designated Gamma Ceti A (officially named Kaffaljidhma , the traditional name for the entire system), B and C.

Nomenclature

''γ Ceti'' ( Latinised to ''Gamma Ceti'') 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. ...

. The designations of the three components as ''Gamma Ceti A'', ''B'' and ''C'' 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). The close pair AB is also designated

HIP In vertebrate anatomy, hip (or "coxa"Latin ''coxa'' was used by Celsus in the sense "hip", but by Pliny the Elder in the sense "hip bone" (Diab, p 77) in medical terminology) refers to either an anatomical region or a joint. The hip region is ...

12706, HD 16970, and HR 804. The system of A, B, and C is collectively designated GJ 106.1 in the Gliese Catalogue of Nearby Stars. Gamma Ceti bore the traditional names of or , derived from ar, الكف الجذماء, rtl=yes ('the cut-short hand'). According to a 1971

NASA The National Aeronautics and Space Administration (NASA ) is an independent agency of the US federal government responsible for the civil space program, aeronautics research, and space research. NASA was established in 1958, succeeding t ...

memorandum, was originally the title for five stars: Gamma Ceti as , Xi¹ Ceti as , Xi² Ceti as ,

Delta Ceti Delta Ceti, Latinized from δ Ceti, is a single, blue-white hued star in the equatorial constellation of Cetus. The star's apparent visual magnitude of +4.06 means it is near to the cusp of the faintest third of the stars that are visibl ...

as and

Mu Ceti Mu Ceti (μ Ceti) is a star in the constellation Cetus. The combined apparent magnitude of the system is +4.27, and it is located 84 light-years from the Sun. In Chinese, (), meaning '' Circular Celestial Granary'', refers to an aste ...

as (excluding

Alpha Ceti Alpha Ceti (α Ceti, abbreviated Alpha Cet, α Cet), officially named Menkar , is the second-brightest star in the constellation of Cetus. It is a cool luminous red giant about 250 light years away. Nomenclature ''Alpha Ceti'' is ...

and

Lambda Ceti Lambda Ceti, Latinisation of names, Latinized from λ Ceti, is B-type star of fifth-magnitude located in the constellation Cetus. Historically, the star bore the traditional name Menkar, although today that name is more commonly associat ...

). The

IAU 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) approved the name ''Kaffaljidhma'' for the component Gamma Ceti A on February 1, 2017. In

Chinese astronomy Astronomy in China has a long history stretching from the Shang dynasty, being refined over a period of more than 3,000 years. The ancient Chinese people have identified stars from 1300 BCE, as Chinese star names later categorized in the twe ...

, , meaning ' Circular Celestial Granary', refers to an asterism consisting of Gamma Ceti, Alpha Ceti, Kappa¹ Ceti, Lambda Ceti, Mu Ceti, Xi¹ Ceti, Xi² Ceti,

Nu Ceti ν Ceti, Romanization of Greek, Latinized as Nu Ceti, is a binary star system in the celestial equator, equatorial constellation of Cetus. It is visible to the naked eye as a faint point of light with a combined apparent visual magnitude ...

, Delta Ceti,

75 Ceti 75 Ceti is a single star in the equatorial constellation of Cetus with at least one planet. It is visible to the naked eye as a dim, orange-hued star with an apparent visual magnitude of +5.36. The star is located 271 light years dis ...

70 Ceti 7 (seven) is the natural number following 6 and preceding 8. It is the only prime number preceding a cube (algebra), cube. As an early prime number in the series of positive integers, the number seven has greatly symbolic associations in religion ...

63 Ceti 63 Ceti is a star in the constellation of Cetus, located just over a degree south of the celestial equator. With an apparent magnitude of about 5.9, the star is barely visible to the naked eye (see Bortle scale) as a dim, orange-hued po ...

and

66 Ceti 66 may refer to: * 66 (number) * One of the years 66 BC, AD 66, 1966, 2066 * "66" (song), a song by Lil Yachty featuring Trippie Redd *66, a song by The Afghan Whigs, from the album 1965 *Sixty-Six (card game), a German card game * ''Sixty Six ...

. Consequently, the Chinese name for Gamma Ceti itself is ('the Eighth Star of Circular Celestial Granary').

Triple system

Gamma Ceti appears to be a triple star system. The inner pair (A and B) 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 2.6

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. The primary component of this pair (A) is an A-type main sequence 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 A3 V and a visual magnitude of 3.6. The fainter secondary component (B) is an F-type main sequence star that has a classification of F3 V and a magnitude of 6.6. The contrasting colors of these two stars makes them a popular target of amateur astronomers. The two can be resolved with a small, aperture telescope under ideal seeing conditions, although at times they can be a challenge to resolve even with a much larger scope. At a wide separation of 840 arcseconds is component C, a dim, magnitude 10.2 K-type star with the designation . It shares a

common proper motion This glossary of astronomy is a list of definitions of terms and concepts relevant to astronomy and cosmology, their sub-disciplines, and related fields. Astronomy is concerned with the study of celestial objects and phenomena that originate outsid ...

with A and is at a very similar distance, but is separated from the close pair by over . It has a

spectral classification 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 ...

of K5V. There are several other stars brighter and closer to Gamma Ceti than – , HD 16985, and – but they are all more distant background stars.

Properties

The measured

angular diameter The angular diameter, angular size, apparent diameter, or apparent size is an angular distance describing how large a sphere or circle appears from a given point of view. In the vision sciences, it is called the visual angle, and in optics, it is ...

of the primary star is . At the estimated distance of this system, this yields a physical size of about 1.9 times the

radius of the Sun Solar radius is a unit of distance used to express the size of stars in astronomy relative to the Sun. The solar radius is usually defined as the radius to the layer in the Sun's photosphere where the optical depth equals 2/3: :1\,R_ = 6.957\t ...

. The secondary component of this system is an X-ray source with a luminosity of . Gamma Ceti is about 300 million years old, and it appears to be a member of the stream of stars loosely associated with the Ursa Major Moving Group. The primary has been examined for an excess of infrared emission that would suggest the presence of circumstellar matter, but none was found.

References

External links

Information about Kaffaljidhma on STARS

Gamma Ceti on AAS WorldWide Telescope
{{DEFAULTSORT:Gamma Ceti Cetus (constellation) Ceti, Gamma Kaffaljidhma Ceti, 86 A-type main-sequence stars F-type main-sequence stars K-type main-sequence stars 012706 016970 0804 Durchmusterung objects