SIMBAD references

We estimated the upper limit masses of an extrasolar planetary system, υ And. Doppler observation of extrasolar planets through the radial velocity displacement of their host stars can determine only lower limits of planetary masses and inevitably involves uncertainties due to the unknown line-of-sight inclination of planetary orbits, 1/sini. However, this inherent uncertainty about mass determination may be compensated by long-term numerical integrations of planetary orbital motions. Our numerical integrations, though our description is limited to only two outer companions around υ And, intend to find any relation between the planetary masses and their dynamical timescales of instability. We integrate the planetary orbits for the Gyr time span with various initial conditions of masses and angle variables to investigate which kind of initial configuration produces stable orbits during the timescale of the υ And host star's age. According to numerical results starting from the Lick Observatory data set, the υ And planetary system is likely to remain stable over the timescale of its host star's age if sini≥0.7. In this case we may estimate that the upper limit masses of the υ And planets in our model are about 1/0.7∼1.43 times larger than their minimum (i.e., when sini=1). However, the instability timescale of the planetary system depends much on its initial orbital configuration due to its chaotic character. Another interesting feature in the orbital motion of the υ And planets is that the longitudes of pericenter of the outer two companions are likely to align, which stabilizes the system. Systems where this orbital alignment is not well achieved easily become unstable.