Upsilon Andromedae c
| Exoplanet | List of exoplanets | |
|---|---|---|
 |
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| Parent star | ||
| Star | Upsilon Andromedae A | |
| Constellation | Andromeda | |
| Right ascension | (α) | 01h 36m 47.8s |
| Declination | (δ) | +41° 24′ 20″ |
| Apparent magnitude | (mV) | 4.09 |
| Distance | 44.0 ± 0.1 ly (13.49 ± 0.03 pc) |
|
| Spectral type | F8V | |
| Mass | (m) | 1.27 (± 0.12) M☉ |
| Radius | (r) | 1.480 (± 0.087) R☉ |
| Temperature | (T) | 6213 (± 44) K |
| Metallicity | [Fe/H] | 0.09 (± 0.06) |
| Age | 3.12 (± 0.2) Gyr | |
| Orbital elements | ||
| Semi-major axis | (a) | 0.830 ± 0.048 AU (~124.1 Gm) |
| ~61.5 mas | ||
| Periastron | (q) | 0.612 ± 0.054 AU (~91.6 Gm) |
| Apastron | (Q) | 1.047 ± 0.077 AU (~9.11 Gm) |
| Eccentricity | (e) | 0.260±0.079 |
| Orbital period | (P) | 241.26±0.64d (~0.66228y) |
| Inclination | (i) | 7.9 ± 1° |
| Argument of periastron |
(ω) | 245.5 ± 5.3° |
| Time of periastron | (T0) | 2,450,158.1 ± 4.5 JD |
| Semi-amplitude | (K) | 55.6 ± 1.7 m/s |
| Physical characteristics | ||
| Mass | (m) |
13.98+2.3 −5.3MJ |
| Discovery information | ||
| Discovery date | April 15, 1999 | |
| Discoverer(s) | Marcy et al. | |
| Discovery method | Radial velocity | |
| Discovery site |
California and Carnegie Planet Search  USA
|
|
| Discovery status | Published | |
| Other designations | ||
|
Samh, 50 Andromedae c, Upsilon Andromedae Ac
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| Database references | ||
| Extrasolar Planets Encyclopaedia |
data | |
| SIMBAD | data | |
| Exoplanet Archive | data | |
| Open Exoplanet Catalogue | data | |
Upsilon Andromedae c (υ Andromedae c, abbreviated Upsilon And c, υ And c), also named Samh, is an extrasolar planet orbiting the Sun-like star Upsilon Andromedae A every 241.2 days. Its discovery in April 1999 by Geoffrey Marcy and R. Paul Butler made this the first multiple-planet system to be discovered around a main-sequence star, and the first multiple-planet system known in a multiple star system. Upsilon Andromedae c is the second known planet in order of distance from its star.
In July 2014 the International Astronomical Union launched a process for giving proper names to certain exoplanets and their host stars. The process involved public nomination and voting for the new names. In December 2015, the IAU announced the winning name was Samh for this planet. The winning name was submitted by the Vega Astronomy Club of Morocco and honours the 11th Century astronomer Ibn al-Samh of Muslim Spain.
Like the majority of known extrasolar planets, Upsilon Andromedae c was detected by measuring variations in its star's radial velocity as a result of the planet's gravity. This was done by making precise measurements of the Doppler shift of the spectrum of Upsilon Andromedae A. At the time of discovery, Upsilon Andromedae A was already known to host one extrasolar planet, the hot Jupiter Upsilon Andromedae b, however by 1999 it was clear that the inner planet could not explain the velocity curve.
In 1999, astronomers at both San Francisco State University and the Harvard-Smithsonian Center for Astrophysics independently concluded that a three-planet model best fit the data. The two new planets were designated Upsilon Andromedae c and Upsilon Andromedae d.
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