HD 28185 and new Hipparcos data reduction: bad news?

View previous topic View next topic Go down

HD 28185 and new Hipparcos data reduction: bad news?

Post by Lazarus on 15th July 2008, 4:20 pm

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 mas
Absolute 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...)
avatar
Lazarus
dG star
dG star

Number of posts : 2805
Registration date : 2008-06-12

View user profile

Back to top Go down

Re: HD 28185 and new Hipparcos data reduction: bad news?

Post by Lazarus on 12th October 2008, 1:16 pm

Apparently the catalogue on the CDS website was faulty and has now been fixed. Here we go again...

HD 28185: new new parallax = 23.62 0.87 mas
Absolute magnitude = 4.68 0.08
Luminosity = 1.15 0.08 solar
Habitable zone inner = 1.01 0.04 AU
Habitable zone outer = 1.23 0.05 AU

Makes prospects somewhat better for habitable moons.
avatar
Lazarus
dG star
dG star

Number of posts : 2805
Registration date : 2008-06-12

View user profile

Back to top Go down

Re: HD 28185 and new Hipparcos data reduction: bad news?

Post by Darkness nova on 12th October 2008, 5:48 pm

Well at least it's still barely within the habitable zone so maybe it's moons would be more like hot desert world or....?

Darkness nova
Asteroid
Asteroid

Number of posts : 69
Location : Octans
Registration date : 2008-06-12

View user profile

Back to top Go down

Re: HD 28185 and new Hipparcos data reduction: bad news?

Post by Lazarus on 31st October 2008, 9:39 am

Minitti et al. (2008) use the old Hipparcos parallax but peg the mass of HD 28185 as 1.24 solar masses, which puts the orbit of the planet at 1.1 AU. This works out as being in the habitable zone for both old and new parallaxes.
avatar
Lazarus
dG star
dG star

Number of posts : 2805
Registration date : 2008-06-12

View user profile

Back to top Go down

Re: HD 28185 and new Hipparcos data reduction: bad news?

Post by Sponsored content


Sponsored content


Back to top Go down

View previous topic View next topic Back to top


 
Permissions in this forum:
You cannot reply to topics in this forum