There's a new reduction of the Hipparcos catalogue available online
here... I wondered if this would result in a change in the habitable status of the planet HD 28185...
Working with visual magnitudes only (this is probably ok, since the Sun and HD 28185 have similar spectral types)
Taking Sol's habitable zone as 0.95-1.15 AU (
from here)
Apparent magnitude = 7.81 (
SIMBAD)
HD 28185: old parallax = 25.28 ± 1.08 mas Absolute magnitude = 4.82 ± 0.09
Luminosity = 1.01 ± 0.04 solar
Habitable zone inner = 0.95 ± 0.04 AU
Habitable zone outer = 1.16 ± 0.05 AU
HD 28185: new parallax = 21.97 ± 0.87 masAbsolute magnitude = 4.52 ± 0.09
Luminosity = 1.33 ± 0.11 solar
Habitable zone inner = 1.10 ± 0.04 AU
Habitable zone outer = 1.33 ± 0.05 AU
Semimajor axis of planet = 1.031 ± 0.060 AU (
Catalog of Nearby Exoplanets)
Looking like a dangerously close call here...
(Of course, this probably will also affect the mass estimate for the star, which will in turn affect the semimajor axis, so...)