star
A star is an astronomical object comprising a luminous spheroid of plasma (physics), plasma held together by its gravity. The List of nearest stars and brown dwarfs, nearest star to Earth is the Sun. Many other stars are visible to the naked ...
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 origins of the e ...
of
Pisces
Pisces may refer to:
* Pisces, an obsolete (because of land vertebrates) taxonomic superclass including all fish
* Pisces (astrology), an astrological sign
* Pisces (constellation), a constellation
**Pisces Overdensity, an overdensity of stars in ...
. ''107 Piscium'' is the star's
Flamsteed designation
A Flamsteed designation is a combination of a number and constellation name that uniquely identifies most naked eye stars in the modern constellations visible from southern England. They are named for John Flamsteed who first used them while co ...
.
John Flamsteed
John Flamsteed (19 August 1646 – 31 December 1719) was an English astronomer and the first Astronomer Royal. His main achievements were the preparation of a 3,000-star catalogue, ''Catalogus Britannicus'', and a star atlas called ''Atlas Coe ...
numbered the stars of Pisces from 1 to 113, publishing his ''Catalogus Britannicus'' in 1725. He accidentally numbered 107 Piscium twice, as he also allocated it the designation of 2 Arietis. This star is faintly visible to the naked eye with an
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 ...
that has been measured varying between 5.14 and 5.26. However, that finding of variation was not confirmed by subsequent observations and is most likely spurious data. It is located at a distance of about away 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 ...
. 107 Piscium is drifting closer to the Sun with a
radial velocity
The radial velocity or line-of-sight velocity, also known as radial speed or range rate, of a target with respect to an observer is the temporal rate of change, rate of change of the distance or Slant range, range between the two points. It is e ...
of −33.6, and is predicted to come as close as in around 135,800 years.
This object is a
K-type main-sequence star
A K-type main-sequence star, also referred to as a K-type dwarf or an orange dwarf, is a main-sequence (hydrogen-burning) star of spectral type K and luminosity class V. These stars are intermediate in size between red M-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 K1V, indicating it is generating energy from
core
Core or cores may refer to:
Science and technology
* Core (anatomy), everything except the appendages
* Core (manufacturing), used in casting and molding
* Core (optical fiber), the signal-carrying portion of an optical fiber
* Core, the centra ...
hydrogen fusion
Stellar nucleosynthesis is the creation (nucleosynthesis) of chemical elements by nuclear fusion reactions within stars. Stellar nucleosynthesis has occurred since the original creation of hydrogen, helium and lithium during the Big Bang. As a ...
. It is somewhat older than the Sun—approximately 6 billion years old. The star has 86% of the mass and 82% of the radius of the Sun, but shines with only 46% of the Sun's luminosity. The
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 ...
of the star is . It is rotating slowly with a period of . The abundance of elements other than hydrogen and helium—the star's
metallicity
In astronomy, metallicity is the abundance of elements present in an object that are heavier than hydrogen and helium. Most of the normal physical matter in the Universe is either hydrogen or helium, and astronomers use the word ''"metals"'' as a ...
—is slightly lower than that of the Sun. The level of
chromospheric activity
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 ...
is similar to the Sun, and it shows a simple cycle of variation.
107 Piscium has been examined for the presence of an
infrared excess
An infrared excess is a measurement of an astronomical source, typically a star, that in their spectral energy distribution has a greater measured infrared flux than expected by assuming the star is a blackbody radiator. Infrared excesses are o ...
caused by
exozodiacal dust
Exozodiacal dust is 1–100 micrometre-sized grains of amorphous carbon and silicate dust that fill the plane of extrasolar planetary systems. It is the exoplanetary analog of zodiacal dust, the 1–100 micrometre-sized dust grains observed in ...
, but none was detected. The
habitable zone
In astronomy and astrobiology, the circumstellar habitable zone (CHZ), or simply the habitable zone, is the range of orbits around a star within which a planetary surface can support liquid water given sufficient atmospheric pressure.J. F. Kas ...
for this star, defined as the locations where liquid water could be present on an Earth-like planet, is at a radius of 0.52– (AU), where is the average distance from the Earth to the Sun.
In 1997, based on data collected 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 star was categorized as an astrometric binary with a period of . However, this result has not been not confirmed.