Evolved stars hint to an external origin of enhanced metallicity in planet-hosting stars

Details Evolved stars hint to an external origin of enhanced metallicity in planet-hosting stars Evolved stars hint to an external origin of enhanced metallicity in planet-hosting stars

2007-07-05

arxiv.org/abs/0707.0788v1

Astronomy and Astrophysics

Astrophysics

A&A, in press

Scientific paper

10.1051/0004-6361:20077814

Exo-planets are preferentially found around high metallicity main sequence stars. We aim at investigating whether evolved stars share this property, and what this tells about planet formation. Statistical tools and the basic concepts of stellar evolution theory are applied to published results as well as our own radial velocity and chemical analyses of evolved stars. We show that the metal distributions of planet-hosting (P-H) dwarfs and giants are different, and that the latter do not favor metal-rich systems. Rather, these stars follow the same age-metallicity relation as the giants without planets in our sample. The straightforward explanation is to attribute the difference between dwarfs and giants to the much larger masses of giants' convective envelopes. If the metal excess on the main sequence is due to pollution, the effects of dilution naturally explains why it is not observed among evolved stars. Although we cannot exclude other explanations, the lack of any preference for metal-rich systems among P-H giants could be a strong indication of the accretion of metal-rich material. We discuss further tests, as well as some predictions and consequences of this hypothesis.

Affiliated with

Also associated with

No associations

Rating

Evolved stars hint to an external origin of enhanced metallicity in planet-hosting stars does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.

If you have personal experience with Evolved stars hint to an external origin of enhanced metallicity in planet-hosting stars, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Evolved stars hint to an external origin of enhanced metallicity in planet-hosting stars will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFWR-SCP-O-569086