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
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
Canis Minor
Canis Minor is a small constellation in the northern celestial hemisphere. In the second century, it was included as an asterism, or pattern, of two stars in Ptolemy's 48 constellations, and it is counted among the 88 modern constellation ...
. It has the
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. ...
G Canis Minoris, the
Gould designation Gould designations for stars are similar to Flamsteed designations in the way that they number stars within a constellation in increasing order of right ascension. Each star is assigned an integer (starting at 1), followed by " G. " (or occasionall ...
50 G. Canis Minoris, and has the HR 3145 identifier from the ''
Bright Star Catalogue
The Bright Star Catalogue, also known as the Yale Catalogue of Bright Stars, Yale Bright Star Catalogue, or just YBS, is a star catalogue that lists all stars of stellar magnitude 6.5 or brighter, which is roughly every star visible to the na ...
''. When first catalogued it was in the
Puppis
Puppis is a constellation in the southern sky. Puppis, the Latin translation of "poop deck", was originally part of an over-large constellation Argo Navis (the ship of Jason and the Argonauts), which centuries after its initial description, was ...
constellation and was designated "13 Puppis", but it subsequently migrated to Canis Minor. Bode gave it the
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. ...
of Lambda Canis Minoris.
Properties
This star has an orange hue and is bright enough to be faintly visible to the naked eye on a dark night, having 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 ...
of +4.39. It is located at a distance of approximately 254
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 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 ...
based on
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 ...
, and is drifting further away 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 +71.6 km/s. The star is considered a member of the
thin disk
The thin disk is a structural component of spiral and S0-type galaxies, composed of stars, gas and dust. It is the main non-centre (e.g. galactic bulge) density, of such matter. That of the Milky Way is thought to have a scale height of around i ...
population. It has one known
exoplanet
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 ...
companion.
The
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 HD 66141 is K2IIIbFe-0.5:, which indicates an
evolved
Evolution is change in the heritable characteristics of biological populations over successive generations. These characteristics are the expressions of genes, which are passed on from parent to offspring during reproduction. Variation t ...
giant star
A giant star is a star with substantially larger radius and luminosity than a main sequence, main-sequence (or ''dwarf'') star of the same effective temperature, surface temperature.Giant star, entry in ''Astronomy Encyclopedia'', ed. Patrick Moo ...
with a mild underabundance of iron. It is an estimated nine billion years old with 0.98 times the
mass of the Sun
The solar mass () is a standard unit of mass in astronomy, equal to approximately . It is often used to indicate the masses of other stars, as well as stellar clusters, nebulae, galaxies and black holes. It is approximately equal to the mass ...
and has expanded to 21 times the Sun's radius. Over 2003 to 2012 a
starspot
Starspots are stellar phenomena, so-named by analogy with sunspots.
Spots as small as sunspots have not been detected on other stars, as they would cause undetectably small fluctuations in brightness. The commonly observed starspots are in gene ...
was periodically dimming its light. The star is radiating 166 times the
luminosity of the Sun
The solar luminosity (), is a unit of radiant flux (power emitted in the form of photons) conventionally used by astronomers to measure the luminosity of stars, galaxies and other celestial objects in terms of the output of the Sun.
One nominal s ...
from its
photosphere
The photosphere is a star's outer shell from which light is radiated.
The term itself is derived from Ancient Greek roots, φῶς, φωτός/''phos, photos'' meaning "light" and σφαῖρα/''sphaira'' meaning "sphere", in reference to it ...
at an
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 4,328 K.
A magnitude 10.32
visual companion
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 ...
was reported by J. Glaisher in 1842. As of 2015, it was located at 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 along a
position angle
In astronomy, position angle (usually abbreviated PA) is the convention for measuring angles on the sky. The International Astronomical Union defines it as the angle measured relative to the north celestial pole (NCP), turning positive into the d ...
of 315°.
Planetary system
From December 2003 to January 2012, the team B.-C. Lee, I. Han, and M.-G. Park observed "HD 66141" with "the fiber-fed Bohyunsan Observatory Echelle Spectrograph (BOES) at Bohyunsan Optical Astronomy Observatory (BOAO)".
In 2012, a long-period, wide-orbiting
planet
A planet is a large, rounded astronomical body that is neither a star nor its remnant. The best available theory of planet formation is the nebular hypothesis, which posits that an interstellar cloud collapses out of a nebula to create a you ...
was deduced by
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 ...