Target Description
    ==================
      XO-3 is a star with a detected substellar companion, XO-3 b, and
      is a target of the Extrasolar Planet Observation and CHaracterization
      (EPOCh) phase of the NASA EPOXI mission.  Other designations for this
      star are GSC 003727-01064 and 2MASS J04215269+5749018.  The star
      has the following astrometric and photometric properties:
 
        Spectral type        : F5V
        Apparent V Magnitude : 9.8
        Distance             : 260 (-/+23) pc
        Mass                 : 1.213 (-/+0.066) solar masses
        Radius               : 1.377 (-/+0.083) solar radii
        RA                   : 04 21 52.705 (FK5, epoch and equinox 2000)
        Dec                  : +57 49 01.89 (FK5, epoch and equinox 2000)
 
      The substellar companion XO-3 b was discovered in 2007 by the XO
      Project (XO).  The known properties of this extrasolar planet are:
 
        Mass               : 11.79 (-/+0.59) Jupiter masses
        Semi major axis    : 0.0454 (+/-0.00082) AU
        Orbital period     : 3.1915239 (-/+0.00023) days
        Eccentricity       : 0.26 (-/+0.017)
        Radius             : 1.217 (-/+0.073) Jupiter radii
        Inclination        : 84.2 (-/+0.54) deg
 
      The astrometric and photometric properties were taken from the
      3 March 2008 update for this planetary system in the Extrasolar
      Planets Encyclopedia.  The encyclopedia is maintained by the Paris
      Observatory and is available online at http://exoplanet.eu.  Please
      consult this web site for the most up-to-date properties.