Veränderlichkeit von τ Andromedae

The Dwarf Nova Pq Andromedae

Apsidal Alignment in Upsilon Andromedae

One of the parameters fitted by Doppler radial velocity measurements of extrasolar planetary systems is ω, the argument of pericenter of a given planet’s orbit referenced to the plane of the sky. Curiously, the ω’s of the outer two planets orbiting Upsilon Andromedae are presently nearly identical: ∆ω ≡ ωD − ωC = 4. 8 ± 4. 8 (1σ). This observation is least surprising if planets C and D occupy o...

Habitability in the Upsilon Andromedae System

We investigate the habitability of the Upsilon Andromedae planetary system as it evolves from a hypothetical four-planet system into what is observed today. We initially considered a fourth planet at a distance of 4.76 AU from the central star. We simulated the dynamics of this system until the fourth planet was ejected due to gravitational interactions with the other planets. Results demonstra...

The Upsilon Andromedae System: Models and Stability

Radial velocity observations of the F8 V star υ Andromedae taken at Lick and at Whipple Observatories have revealed evidence of three periodicities in the line-ofsight velocity of the star. These periodicities have been interpreted as evidence for at least three low mass companions (LMCs) revolving around υ Andromedae. The mass and orbital parameters inferred for these companions raise question...

The Planetary System of Upsilon Andromedae

The bright F8 V solar-type star upsilon Andromedae has recently been reported to have a system of three planets of Jovian masses. In order to investigate the orbital stability and mutual gravitational interactions among these extrasolar planets, both forward and backward integrations from the latest observed orbital elements for all three planets' orbits have been performed under the coplanar a...