Upsilon Andromedae AB

Star type

g A: F8 V
g B: M4.5 V

Distance from Earth
g 43.93 ly

Star Service No.
g NA

Age
g A: A bit younger than Sol
g B: NA

Diameter/Mass/Temp (xSol)
g A: NA; 120%; NA
g B: NA; 20% ; NA

Brightness (xSol)
g A: 365%
g B: NA

Metallicity
g A: NA
g B: NA

Comparison to Sol
g A: NA
g B: NA

Picture of star
g A: See artist's illustration at upper right; planet Ad is in the illustration's upper left corner (illustration courtesy of NASA, ESA, and A. Feild (STScI))
g B: NA

Star system features
g NA

Known planets
g A: Planet “Upsilon Andromedae Ab” is a hot Jupiter; it circles sun once every 4.6 days, is tidally locked; outer atmosphere is circulating much faster than interior atmosphere; temp difference between hot and cold sides is 2550 F. Two other Jupiter-type planets are farther out then “Ab”; their orbits are at a steep angle to each other. There are hints that a fourth planet, “Ae”, orbits the star much farther out.
g B: NA

Habitable zones
g A: The giant planets with wacky orbits likely affect any Earth-like planets in the same system. A smaller planet might fluctuate between being habitable and being inhospitable to life because of the forces exerted by the neighboring giant planets with eccentric orbits. These forces could cause the orbit of the smaller planet to repeatedly elongate and then become circular again in as little as 1,000 years, causing significant temperature variations. For part of the time, liquid water could exist on the surface, but at others it would boil off. For an Earth-like planet at the outer edge of its habitable zone, the alteration in orbit could take it too far from its star, leading to planetary glaciations. In addition, the smaller planet's geological properties likely would change over very long timescales, cycling in and out of intense volcanism and earthquake stages. Tidal forces also would fix the planet’s rotation period, and as the orbit becomes more elongated the length of day would change significantly - almost day to day.
g B: NA

Orbital map

g A: Orbits of two planets (Ac and Ad) are inclined by 30 degrees with respect to each other, which as of 2010 as not been seen in any other planetary system; see illustration at right for comparison of our solar system and the Upsilon Andromedae System in the polar view. (llustration courtesy of NASA, ESA, and A. Feild (STScI))
g B: NA

View from stars
g NA

Nearby stars
(Star systems with 10 light years)
g NA

Map locating star system
g NA

Location in Earth sky
g In constellation Andromeda

Other names
g A: Ups And; HR 458
g B: NA

Sci-fi mentions
g A: Home system of the hostile alien species the Narrat in “Ace of Aces” novel by Chris Berman
g B: NA

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