   #copyright

47 Ursae Majoris c

2007 Schools Wikipedia Selection. Related subjects: Space (Astronomy)

   CAPTION: 47 Ursae Majoris c

     Extrasolar planet    Lists of extrasolar planets
                      Parent star
   Star                   47 Ursae Majoris
   Constellation          Ursa Major
   Right ascension    (α) 10^h 59^m 28.0^s
   Declination        (δ) +40° 25′ 49″
   Spectral type          G1V
                   Orbital elements
   Semimajor axis     (a) 3.79 ± 0.24 AU
   Eccentricity       (e) 0.00 ± 0.12
   Orbital period     (P) 2594 ± 90 d
   Inclination        (i)  ?°
   Longitude of
   periastron         (ω) 127 ± 56°
   Time of periastron (τ) 2,451,360 ± 500 JD
               Physical characteristics
   Mass               (m) >0.79 ± 0.13 M[J]
   Radius             (r)  ? R[J]
   Density            (ρ)  ? kg/ m^3
   Temperature        (T)  ? K
                 Discovery information
   Discovery date         2002
   Discoverer(s)          Fischer, Butler,
                          Marcy, et al.
   Detection method       Doppler Spectroscopy
   Discovery status       Confirmed

   47 Ursae Majoris c is an extrasolar planet orbiting the Sun-like star
   47 Ursae Majoris, making one orbital revolution every 2,594 days. The
   planet was discovered in 2002 and has a mass at least 79% that of
   Jupiter. 47 Ursae Majoris is the outermost known planet in its
   planetary system.

Discovery

   Like the majority of known extrasolar planets, 47 Ursae Majoris c was
   discovered by detecting changes in its star's radial velocity caused by
   the planet's gravity. This was done by measuring the Doppler shift of
   the star's spectrum.

   At the time of discovery, 47 Ursae Majoris was already known to host
   one extrasolar planet, designated 47 Ursae Majoris b. Further
   measurements of the radial velocity revealed another periodicity in the
   data unaccounted for by the first planet. This periodicity could be
   fitted by assuming a second planet, designated 47 Ursae Majoris c
   existed in the system with an orbital period close to 7 years.
   Observations of the photosphere of 47 Ursae Majoris suggest that the
   periodicity could not be explained by stellar activity, making the
   planet interpretation more likely. The planet was announced in 2002.

Orbit and mass

   47 Ursae Majoris c orbits further out than the previously-known planet
   47 Ursae Majoris b, at a distance comparable to that of the outer
   asteroid belt in our solar system. It is slightly less massive than
   Jupiter. The orbital eccentricity is not well constrained, but it is
   likely to be low. The planet is located close to the 5:2 orbital
   resonance with 47 Ursae Majoris b, a similar configuration to Jupiter
   and Saturn in our solar system. In addition, the ratio of the masses of
   47 Ursae Majoris b and c is similar to the mass ratio of Jupiter and
   Saturn.

   A limitation of the radial velocity method used to detect 47 Ursae
   Majoris c is that only a lower limit on the planet's mass can be
   obtained. This lower limit is 0.792 times the mass of Jupiter.
   Stability considerations suggest that the true mass of the planet is
   likely to lie close to this lower limit.

Characteristics

   Since 47 Ursae Majoris c was detected indirectly, properties such as
   its radius, composition and temperature are unknown. Based on its high
   mass, the planet is likely to be a gas giant with no solid surface.

   Retrieved from " http://en.wikipedia.org/wiki/47_Ursae_Majoris_c"
   This reference article is mainly selected from the English Wikipedia
   with only minor checks and changes (see www.wikipedia.org for details
   of authors and sources) and is available under the GNU Free
   Documentation License. See also our Disclaimer.
