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Limiting Magnitude: 10.7
Universal Time: 18.10.2007 10:04:57
Local Time: 18.10.2007 20:04:57
Name: Nunki
Catalogue number: HIP92855
Object type: Multiple Star
Bayer: Sigma
Flamsteed/other: 34
HIP number: 92855
TYC number: TYC6868-1829-1
Rises: Today at 09:54:17
Transit: Today at 17:26:53
Sets: Tomorrow at 00:59:30
Constellation name: Sagittarius
Constellation common name: The Archer
Constellation possessive form: Sagittarii
Azimuth: 277° 29.207'
Altitude: 54° 53.153'
RA (JNow): 18h 55.757m
Dec (JNow): -26° 17.314'
RA (J2000): 18h 55.266m
Dec (J2000): -26° 17.810'
Distance from observer: 224.94 ly
Distance from Sun: 224.94 ly
Proper motion RA: 0.0136 arcsec/ year
Proper motion Dec: -0.0524 arcsec/ year
Variability: tiny, < 0.06 Mag
Radius: 7.5 solar radii
Double/multiple: binary, > 10" sep
Apparent magnitude: 2.03
Absolute magnitude: -2.16 (visual)
Temperature: 12865 Kelvin
B-V colour: -0.13
Luminosity: 1392 suns
Description: Nunki is a main sequence star, a star that burns hydrogen in its core. Every star spends most of its lifetime as a main sequence star. The properties of a main sequence star are determined completely by its mass, which can range from 1/20 the mass of the sun up to 50 times the mass of the sun. The more massive a star is, the hotter and brighter it will be, and the shorter it will live. A star's temperature also determines its colour. The hottest stars appear blue. Slightly cooler stars appear white or yellow, and the coolest stars appear orange or red. Our sun is slightly hotter and more massive than the average star on the main sequence.Nunki is both a variable star and one member of a multiple star system. It is possible that this star is an ‘eclipsing variable’. Eclipsing variables are members of a double star system which pass directly in front of their companion stars during their orbit. When this happens, light from the companion star is blocked, and the binary star appears fainter to observers on Earth. The most famous eclipsing binary is Algol, nicknamed ‘the Demon Star’ for its spooky changes in brightness.
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