11 Ursae Minoris is a single star located approximately 410 light years away in the northern

circumpolar constellation A circumpolar star is a star that, as viewed from a given latitude on Earth, never sets below the horizon due to its apparent proximity to one of the celestial poles. Circumpolar stars are therefore visible from said location toward the nearest po ...

Ursa Minor Ursa Minor (Latin: 'Lesser Bear', contrasting with Ursa Major), also known as the Little Bear, is a constellation located in the far northern sky. As with the Great Bear, the tail of the Little Bear may also be seen as the handle of a ladle, ...

. The star is visible to the naked eye as a faint, orange-hued star 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 ...

of 5.15. It is moving closer to the Earth with a heliocentric radial velocity of −17.5 km/s. This is an aging K-type

giant star A giant star is a star with substantially larger radius and luminosity than a main-sequence (or ''dwarf'') star of the same surface temperature.Giant star, entry in ''Astronomy Encyclopedia'', ed. Patrick Moore, New York: Oxford University Press ...

with a stellar classification of K4 III. It is 1.2 billion years old with twice the mass of the Sun. As a consequence of exhausting the hydrogen at its

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 ...

, the star has expanded to 28 times the Sun's radius. It is radiating 258 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 ...

from its swollen photosphere at an effective temperature of 4,358 K. 11 Ursae Minoris is sometimes named ''Pherkard'' or ''Pherkad Minor'', the later name to distinguish it from ''Pherkad'' (Major) which is γ Ursae minoris. It has also been designated as γ¹ Ursae minoris, in which case the brighter Pherkad is called γ² Ursae minoris, but these names are rarely used. ''11 Ursae Minoris'' is the

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 ...

. 11 Ursae minoris has a detected planet discovered in August 2009.

Planetary system

11 Ursae minoris b was discovered during a radial velocity survey of 62 K type Red giant stars using the 2m Alfred Jensch telescope of the Thuringian State Observatory in

Germany Germany,, officially the Federal Republic of Germany, is a country in Central Europe. It is the second most populous country in Europe after Russia, and the most populous member state of the European Union. Germany is situated betwe ...

References

External links

* {{Sky, 15, 17, 05.8886, +, 71, 49, 26.044, 389.8 K-type giants Planetary systems with one confirmed planet Ursa Minor (constellation) BD+72 0678 Ursae Minoris, 11 136726 074793 5714

Planetary system

See also

References

External links