Monday, January 21, 2008

Gl 451 AB

Star type
g A: G8VI
g B: M (Observations announced in 1998 suggest that sightings of this companion were actually observations of a new gargantuan class of stellar mass ejection associated recently with Sol-type stars of spectral class F8 to G8 called a "superflare" from the primary star itself .)

Distance from Earth
g 28.12 ly

Star Service No.
g NA

g A: Probably 3.24 Gyr but may be at least 5.4 billion years old based on chromospheric anaysis alone, but its halo subdwarf status would suggest that the star is at least 10 billion years old, having formed during a period of rapid collapse that lasted perhaps a billion years in the early history of the Milky Way galaxy prior the development of the galactic disk.
g B: NA

Diameter/Mass/Temp (xSol)
g A: 64%; 60.5%; NA
g B: NA; 15.4%; NA

Brightness (xSol)
g A: 17.2169%-19% (Emits enormous magnetic outbursts produce "superflares", aka coronal mass ejections, that release between 100 and 10 million times more energy than the largest flares ever observed on the sun, making them brighten briefly by up to 20 times. These superflares last from one hour to one week and increase the normal luminosity of a star as much as one thousand times. They occur, on average, about once per century.)
g B: 0.1428%

g A: Lower than Sol
g B: NA

Comparison to Sol
g A: See chart (similar to Sun)
g B: See chart (similar to Proxima)

Picture of star
g A: NA
g B: NA

Star system features
g NA

Known planets
g A: Given the low abundance of elements heavier than hydrogen, the star is more likely to have gas giants in cold outer orbits than rocky planets in close orbit.
g B: NA

Habitable zone
g A: Given the regular eruption of superflares, it is unlikely that Earth-type life could survive for long on any inner rocky planet (If Sol were to produce a large superflare, Earth's ozone layer would be destroyed, and ice on the daylight side of moons as far out as those of Jupiter or even Saturn would be melted, producing vast floodplains that refreeze after the flare subsides. ). The distance where an Earth-type planet would be comfortable with liquid water is only about 0.44 AU (around the orbit of Mercury).
g B: NA

Orbital map
g NA

View from star
g NA

Nearby stars
(Star systems with 10 light years)
g BD+36 2219 AB: 2.3 ly
g 61 Ursae Majoris (G8 Ve): 2.6 ly
g Chara (G0 V): 5.0
g Alula Australis 4? (C=G0-5 Ve): 5.4 ly
g G 122-49: 6.2 ly
g Ross 1003: 6.9 ly
g Gl 436 / AC+27 28217: 7.1 ly
g GJ 1138: 7.4 ly
g GJ 1134: 9.1 ly
g Beta Comae Berenices (B=G0 V): 10.0 ly

Map locating star system
g NA

Location in Earth sky
g In the southern part of Constellation Ursa Major, the Great Bear, which also encompasses the Big Dipper, northeast of Alula Borealis (Nu Ursae Majoris) and Alula Australis (Xi or Ksi Ursae Majoris)

Other names
g A: HR 4550; Hip 57939; HD 103095; BD+38 2285; SAO 62738; FK5 1307; G 122-51; G 148-18; LHS 44; LTT 13276; LFT 855; Gmb 1830; Groombridge 1830; NSV 5374
g B: CF Uma; CF Ursa Major; BD +38° 2285; YPC2745.00; CF Ursae Majoris

Sci-fi mentions
g NA

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