Pi1 Ursae Majoris
Encyclopedia
Pi¹ Ursae Majoris is a yellow G-type
main sequence dwarf
with a mean apparent magnitude
of +5.63. It is approximately 46.8 light years
from Earth
, and is a relatively young star with an age of about 200 million years. It is classified as a BY Draconis type
variable star
and its brightness varies by 0.08 magnitudes. In 1986, it became the first solar-type star to have the emission from an X-ray flare observed. Based upon its space velocity
components, this star is a member of the Ursa Major moving group
of stars that share a common motion through space.
An excess of infrared
radiation has been detected from this system, which suggests the presence of a debris disk
. The best fit to the data indicates that there is a ring of fine debris out to a radius of about 0.4 AU
, consisting of 0.25 μm grains of amorphous silicates or crystalline forsterite. There may also be a wider ring of larger (10 μm) grains out to a distance of 16 AU.
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...
main sequence dwarf
Main sequence
The main sequence is a continuous and distinctive band of stars that appears on plots of stellar color versus brightness. These color-magnitude plots are known as Hertzsprung–Russell diagrams after their co-developers, Ejnar Hertzsprung and Henry Norris Russell...
with a mean apparent magnitude
Apparent magnitude
The apparent magnitude of a celestial body is a measure of its brightness as seen by an observer on Earth, adjusted to the value it would have in the absence of the atmosphere...
of +5.63. It is approximately 46.8 light years
Light Years
Light Years is the seventh studio album by Australian recording artist Kylie Minogue. It was released on 25 September 2000 by Parlophone and Mushroom Records. The album's style was indicative of her return to "mainstream pop dance tunes"....
from Earth
Earth
Earth is the third planet from the Sun, and the densest and fifth-largest of the eight planets in the Solar System. It is also the largest of the Solar System's four terrestrial planets...
, and is a relatively young star with an age of about 200 million years. It is classified as a BY Draconis type
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...
variable star
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...
and its brightness varies by 0.08 magnitudes. In 1986, it became the first solar-type star to have the emission from an X-ray flare observed. Based upon its space velocity
Space velocity
Space velocity may be about,* Space velocity , the velocity of a star in the Galactic coordinate system.* Space velocity , the relation between volumetric flow and reactor volume in a chemical reactor....
components, this star is a member of the Ursa Major moving group
Ursa Major Moving Group
The Ursa Major Moving Group, also known as Collinder 285 or Ursa Major association, is a nearby stellar moving group, a set of stars with common velocities in space and thought to have a common origin. Its core is located roughly 80 light years away...
of stars that share a common motion through space.
An excess of 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...
radiation has been detected from this system, which suggests the presence of a 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...
. The best fit to the data indicates that there is a ring of fine debris out to a radius of about 0.4 AU
Astronomical unit
An astronomical unit is a unit of length equal to about or approximately the mean Earth–Sun distance....
, consisting of 0.25 μm grains of amorphous silicates or crystalline forsterite. There may also be a wider ring of larger (10 μm) grains out to a distance of 16 AU.