Kappa¹ Ceti, Latinized from κ¹ Ceti, is a

variable Variable may refer to: * Variable (computer science), a symbolic name associated with a value and whose associated value may be changed * Variable (mathematics), a symbol that represents a quantity in a mathematical expression, as used in many ...

yellow dwarf star approximately 30 light-years away 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 of

Cetus Cetus () is a constellation, sometimes called 'the whale' in English. The Cetus was a sea monster in Greek mythology which both Perseus and Heracles needed to slay. Cetus is in the region of the sky that contains other water-related constellat ...

. The star was discovered to have a rapid rotation, roughly once every nine days. Though there are no

extrasolar planet An exoplanet or extrasolar planet is a planet outside the Solar System. The first possible evidence of an exoplanet was noted in 1917 but was not recognized as such. The first confirmation of detection occurred in 1992. A different planet, init ...

s confirmed to be orbiting the star, Kappa¹ Ceti is considered a good candidate to contain

terrestrial planet A terrestrial planet, telluric planet, or rocky planet, is a planet that is composed primarily of silicate rocks or metals. Within the Solar System, the terrestrial planets accepted by the IAU are the inner planets closest to the Sun: Mercury, ...

s, like the

Earth Earth is the third planet from the Sun and the only astronomical object known to harbor life. While large volumes of water can be found throughout the Solar System, only Earth sustains liquid surface water. About 71% of Earth's surfa ...

. The system is a candidate binary star, but has not been confirmed.

Description

Kappa¹ Ceti is a yellow dwarf star of the

spectral type 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 ...

G5Vv. Since 1943, the

spectrum A spectrum (plural ''spectra'' or ''spectrums'') is a condition that is not limited to a specific set of values but can vary, without gaps, across a continuum. The word was first used scientifically in optics to describe the rainbow of colors ...

of this star has served as one of the stable anchor points by which other stars are classified. The star has roughly the same mass as 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 ...

, with 95% of the Sun's radius but only 85 percent of the luminosity. Its brightness varies by a few hundredths of a magnitude over a period of nine days and it is classified as a

BY Draconis variable BY Draconis variables are variable stars of late spectral types, usually K or M, and typically belong to the main sequence. The name comes from the archetype for this category of variable star system, BY Draconis. They exhibit variations in thei ...

, a type of variable star where the brightness changes are due to spots on its surface as it rotates. The rapid rotation rate of this star, approximately once every nine days, is indicative of a relatively youthful body several hundred million years in age. Due to starspots, the star varies slightly over approximately the same period. The variations in the period are thought to be caused by differential rotation at various latitudes, similar to what happens on the surface of the Sun. The starspots on Kappa¹ Ceti range in latitude from 10° to 75° The magnetic properties of this star make it "an excellent match for the Sun at a key point in the Earth's past". According to recent hypotheses, unusually intense stellar flares from a solar twin star could be caused by the interaction of the magnetic field of a giant planet in a tight orbit with that star's own magnetic field. Some Sun-like stars of

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 ...

F8 to G8 have been found to undergo enormous magnetic outbursts to produce so-called superflares ( coronal mass ejections) that release between 100 and 10 million times more energy than the largest flares ever observed on the sun, making them brighten briefly by up to 20 times. Magnetic field measurements for κ1 Cet were reported in 2016. These authors used spectropolarimetric observations from NARVAL to reconstruct the magnetic field topology and to quantitatively investigate the interactions between the stellar wind and a possible surrounding planetary system. A magnetic field detection was reported for κ1 Cet., with an average field strength of 24 G, and a maximum value of 61 G. Stellar wind model shows a mass-loss rate of ·yr⁻¹, i.e., 50 times larger than the current solar wind mass-loss rate. Recent data constrained model of the star suggests that its mass loss rate is as high as 100 times of the solar mass-loss rate. The space velocity components of this star are = . It is not known to be a member of a

moving group In astronomy, stellar kinematics is the observational study or measurement of the kinematics or motions of stars through space. Stellar kinematics encompasses the measurement of stellar velocities in the Milky Way and its satellites as well a ...

of stars.

References

External links

* * * {{DEFAULTSORT:Kappa1 Ceti G-type main-sequence stars Ceti, 96 Cetus (constellation) Ceti, Kappa1 Durchmusterung objects Ceti, 96 0137 020630 015457 0996

Description

See also

References

External links