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Kappa1 Ceti, Latinized from κ1 Ceti, is a variable yellow dwarf
Kappa1 Ceti has a spectrm of G5Vv, classifying it as a G dwarf that fuses hydrogen into helium on its
star
A star is a luminous spheroid of plasma (physics), plasma held together by Self-gravitation, self-gravity. The List of nearest stars and brown dwarfs, nearest star to Earth is the Sun. Many other stars are visible to the naked eye at night sk ...
approximately 30 light-year
A light-year, alternatively spelled light year (ly or lyr), is a unit of length used to express astronomical distances and is equal to exactly , which is approximately 9.46 trillion km or 5.88 trillion mi. As defined by the International Astr ...
s away in the 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 first constellati ...
of Cetus
Cetus () is a constellation, sometimes called 'the whale' in English. The Cetus (mythology), 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- ...
.
Bayer used the designations κ Ceti and g Tauri for the same star. g Tauri is now no longer used.
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 confirmed detection of an exoplanet was in 1992 around a pulsar, and the first detection around a main-sequence star was in 1995. A different planet, first detect ...
s confirmed to be orbiting the star, Kappa1 Ceti is considered a good candidate to contain terrestrial planet
A terrestrial planet, tellurian 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 ...
s, like the Earth
Earth is the third planet from the Sun and the only astronomical object known to Planetary habitability, harbor life. This is enabled by Earth being an ocean world, the only one in the Solar System sustaining liquid surface water. Almost all ...
. The system is a candidate 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 ...
, but has not been confirmed.
Description
Kappa1 Ceti has a spectrm of G5Vv, classifying it as a G dwarf that fuses hydrogen into helium on its core
Core or cores may refer to:
Science and technology
* Core (anatomy), everything except the appendages
* Core (laboratory), a highly specialized shared research resource
* Core (manufacturing), used in casting and molding
* Core (optical fiber ...
. Since 1943, the spectrum
A spectrum (: spectra or spectrums) is a set of related ideas, objects, or properties whose features overlap such that they blend to form a continuum. The word ''spectrum'' was first used scientifically in optics to describe the rainbow of co ...
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 centre of the Solar System. It is a massive, nearly perfect sphere of hot plasma, heated to incandescence by nuclear fusion reactions in its core, radiating the energy from its surface mainly as visible light a ...
, with 95% of the Sun's radius and 88 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 young star; its age is estimated to be between 300 and 400 million years. 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
A coronal mass ejection (CME) is a significant ejection of plasma mass from the Sun's corona into the heliosphere. CMEs are often associated with solar flares and other forms of solar activity, but a broadly accepted theoretical understanding ...
) 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 Ceti 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 Ceti, 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 of stars.
See also
*List of star systems within 25–30 light-years
This is a list of star systems within 25–30 light-years of Earth. List
See also
* List of nearest stars
* List of star systems within 20–25 light-years
* List of star systems within 30–35 light-years
* Lists of stars
* List of nearest ...
* List of nearest G-type stars
References
External links
* * * {{DEFAULTSORT:Kappa1 Ceti G-type main-sequence stars Ceti, 96 Cetus Ceti, Kappa1 Durchmusterung objects Ceti, 96 0137 020630 015457 0996