HD 12039
Encyclopedia
HD 12039 is a variable star
in the constellation
of Cetus
. It is categorized as a BY Draconis variable
, and has a stellar classification
that is similar to our own Sun
.
Recently a debris field was discovered in orbit around this star using infrared
observations by the Spitzer telescope
. This debris is thought to be an asteroid
belt. The measured temperature of the debris is 110°K, which places it in an orbit between 4 and 6 AU
from the star, or about the same distance where Jupiter
orbits our Sun. This debris disk
may have been created by the breakup of a single, 100 km diameter planetesimal
through a collision. The star system does not show any excess emission at 70 μm, indicating it does not have a cold outer dust disk.
The star was examined for the presence of an extrasolar planet
with a mass in the range 2-10 Jupiter masses and an orbital distance of 3-15.5 AU
. Instead, a close stellar companion was likely discovered. This object is separated from the primary by 0.15 arcseconds, making it unlikely to be a background object.
This star has been proposed as a member of the Tucana-Horoglium Association (T-WA), a stream of young stars with a common motion through space. The T-WA association is about 30 million years old. However, this star has an estimated age of only 7.5−8 million years. The space velocity components of this star are U = −0.6, V = −16.3 and W = 5.0 km/s. It is orbiting the Milky Way
galaxy with an orbital eccentricity
of 0.06, with a distance that varies from 7.11−8.01 kpc of the galactic core. The inclination
of its orbit carries it as far as 90 parsecs above the galactic plane.
Variable star
A star is classified as variable if its apparent magnitude as seen from Earth changes over time, whether the changes are due to variations in the star's actual luminosity, or to variations in the amount of the star's light that is blocked from reaching Earth...
in the constellation
Constellation
In modern astronomy, a constellation is an internationally defined area of the celestial sphere. These areas are grouped around asterisms, patterns formed by prominent stars within apparent proximity to one another on Earth's night sky....
of Cetus
Cetus
Cetus is a constellation. Its name refers to Cetus, a sea monster in Greek mythology, although it is often called 'the whale' today. Cetus is located in the region of the sky that contains other water-related constellations such as Aquarius, Pisces, and Eridanus.-Ecliptic:Although Cetus is not...
. It is categorized as a BY Draconis variable
BY Draconis variable
BY Draconis variables are main sequence variable stars of late spectral types, usually K or M. The name comes from the archetype for this category of variable star system, BY Draconis. They exhibit variations in their luminosity due to rotation of the star coupled with star spots, and other...
, and has a stellar classification
Stellar classification
In astronomy, stellar classification is a classification of stars based on their spectral characteristics. The spectral class of a star is a designated class of a star describing the ionization of its chromosphere, what atomic excitations are most prominent in the light, giving an objective measure...
that is similar to our own Sun
Sun
The Sun is the star at the center of the Solar System. It is almost perfectly spherical and consists of hot plasma interwoven with magnetic fields...
.
Recently a debris field was discovered in orbit around this star using infrared
Infrared
Infrared light is electromagnetic radiation with a wavelength longer than that of visible light, measured from the nominal edge of visible red light at 0.74 micrometres , and extending conventionally to 300 µm...
observations by the Spitzer telescope
Spitzer Space Telescope
The Spitzer Space Telescope , formerly the Space Infrared Telescope Facility is an infrared space observatory launched in 2003...
. This debris is thought to be an asteroid
Asteroid
Asteroids are a class of small Solar System bodies in orbit around the Sun. They have also been called planetoids, especially the larger ones...
belt. The measured temperature of the debris is 110°K, which places it in an orbit between 4 and 6 AU
Astronomical unit
An astronomical unit is a unit of length equal to about or approximately the mean Earth–Sun distance....
from the star, or about the same distance where Jupiter
Jupiter
Jupiter is the fifth planet from the Sun and the largest planet within the Solar System. It is a gas giant with mass one-thousandth that of the Sun but is two and a half times the mass of all the other planets in our Solar System combined. Jupiter is classified as a gas giant along with Saturn,...
orbits our Sun. This debris disk
Debris disk
A debris disk is a circumstellar disk of dust and debris in orbit around a star. Sometimes these disks contain prominent rings, as seen in the image of Fomalhaut on the right. Debris disks have been found around both evolved and young stars, as well as at least one debris disk in orbit around a...
may have been created by the breakup of a single, 100 km diameter planetesimal
Planetesimal
Planetesimals are solid objects thought to exist in protoplanetary disks and in debris disks.A widely accepted theory of planet formation, the so-called planetesimal hypothesis of Viktor Safronov, states that planets form out of cosmic dust grains that collide and stick to form larger and larger...
through a collision. The star system does not show any excess emission at 70 μm, indicating it does not have a cold outer dust disk.
The star was examined for the presence of an extrasolar planet
Extrasolar planet
An extrasolar planet, or exoplanet, is a planet outside the Solar System. A total of such planets have been identified as of . It is now known that a substantial fraction of stars have planets, including perhaps half of all Sun-like stars...
with a mass in the range 2-10 Jupiter masses and an orbital distance of 3-15.5 AU
Astronomical unit
An astronomical unit is a unit of length equal to about or approximately the mean Earth–Sun distance....
. Instead, a close stellar companion was likely discovered. This object is separated from the primary by 0.15 arcseconds, making it unlikely to be a background object.
This star has been proposed as a member of the Tucana-Horoglium Association (T-WA), a stream of young stars with a common motion through space. The T-WA association is about 30 million years old. However, this star has an estimated age of only 7.5−8 million years. The space velocity components of this star are U = −0.6, V = −16.3 and W = 5.0 km/s. It is orbiting the Milky Way
Milky Way
The Milky Way is the galaxy that contains the Solar System. This name derives from its appearance as a dim un-resolved "milky" glowing band arching across the night sky...
galaxy with an orbital eccentricity
Orbital eccentricity
The orbital eccentricity of an astronomical body is the amount by which its orbit deviates from a perfect circle, where 0 is perfectly circular, and 1.0 is a parabola, and no longer a closed orbit...
of 0.06, with a distance that varies from 7.11−8.01 kpc of the galactic core. The inclination
Inclination
Inclination in general is the angle between a reference plane and another plane or axis of direction.-Orbits:The inclination is one of the six orbital parameters describing the shape and orientation of a celestial orbit...
of its orbit carries it as far as 90 parsecs above the galactic plane.