70 Ophiuchi AB

Star type
g A: K0-1 Ve
g B: K5-6 Ve

Distance from Earth
g 16.6 ly

Star Service No.
g NA

Age
g A: 3.998 billion years
g B: 5.441 billion years

Diameter/Mass/Temp (xSol)
g A: 89%; 92%; 5290 K
g B: 73%; 70%; 4250 K

Brightness (xSol)
g A: 49%
g B: 8.4% to 9%

Metallicity
g A: 30% to 100% (probably about 73%)
g B: 73%

Comparison to Sol
g See illustration (stars are similar to Alpha Centauri B and GJ205)

Picture of star
g A and B: See picture
g A: See picture

Star system features
g Stars A and B have a relatively wide separation, on average by a semi-major axis of 23.2 AUs (4.554") in a highly elliptical orbit (e= 0.499) that takes 83.38 years to complete. The distance separating the two stars varies from 11.4 and 34.8 AUs; they are always separated from each other by roughly the orbital distance of Saturn in the Solar System. Lastly, the inclination of the orbit is 121.2° from the perspective of an observer on Earth. The last close approach was in 1984, the next greatest separation will be in 2028.
g Future: System is near its closest approach to the Sun, the distance shortening to 15 light years 75,000 years from now

Known planets
g A: None
g B: None

Habitable zone
g A: The orbital distance where an Earth-type planet would have liquid water is centered around 0.68 AU, near the Venus-Sun distance in the Solar System, where a planet's period would be about 228 days or almost two thirds of an Earth year; probability of a habitable planet is 5.7%
g B: Orbital distance where an Earth-type planet would have liquid water is centered around 0.30 AU, or three fourths of Mercury's orbital distance in the Solar System, where the orbital period would be over 77 days; probability of a habitable planet is less than 0.1%

Orbital map
g See map

View from star
g A: See sky map
g A: Artist’s interpretation of the 70 Ophiuchi system seen from a hypothetical moon-like world orbiting about the primary sun. The secondary, orange colored sun (70 Ophiuchi B) is seen in the distance to the upper right.
g B: NA (but virtually identical to Star A)

Nearby stars
(Star systems with 10 light years)
g Ross 652 A/Van Biesbroeck's: 6.1 ly
g Hip 85605: 6.7 ly
g Wolf 630 A-C: 6.7 ly
g Altair: 7.8 ly
g BD-12 4523 AB: 7.9 ly
g Wolf 629 AB: 8.2 ly
g BD-03 4233: 9.1 ly
g BD+02 3312: 9.3 ly
g Ross 154: 9.3 ly
g G 154-44: 9.9 ly

Map locating star system
g See stellar map

Location in Earth sky
g In the northeastern part of Constellation Ophiuchus, the Serpent Holder, east of Gamma Ophiuchi

Other names
g Gliese 702 AB
g A: HD 165341
g A: HIP 88601
g A: LHS 458
g A-B: 70 Oph AB
g A: HR 6752
g A-B: Gl 702 AB
g A: SAO 123107
g A: ADS 11046 A
g A: Struve 2272 A
g B: LHS 459
g B: Gl 702 B
g B: ADS 11046 B
g B: Struve 2272 B

Sci-fi mentions
g Dune and other novels in the Dune universe by Frank Herbert. Sikun is the third planet from 70 Ophiuchi.
g The Ophiuchi Hotline, novel by John Varley. Humanity survives with the aid of a technology derived from information in the Ophiuchi Hotline, a radio signal apparently beamed from the star 70 Ophiuchi.
g Frontier: Elite II and Frontier: First Encounters, computer games. This system has a mining and heavy industry based economy. For a mining system, its population of hundreds of thousands of people is impressive

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