Observational projects
I am currently involved with three observational projects.


Extremely large 18O abundance in HdC stars
A search for N in extremely metal-poor stars
MIRIAD
Other

Extremely large 18O abundance in HdC stars

The PI of this project is Geoff Clayton (Louisiana State University). He and his team discovered a really bizarre 18O abundance in a Hydrogen-deficient Carbon (HdC) star (ApJ Letter). I tried to come up with at least some ideas for what the stellar evolution origin for such a thing could be. Accourding to the initial data the HdC star HD 137613 has 16O / 18O \leq 1. In terms of stellar nucleosynthesis this is extremely extreme, and extremely hard to understand. So, what do you do? Of course, get more data. So we have Gemini time now to search for more crazy stars like this ... until it becomes a real problem.

A search for N in extremely metal-poor stars

With so many C-rich EMP stars around, and at least for the s-process rich CEMP-s stars we believe these are in fact mass-transfer binaries, shouldn't there be some N-rich EMP stars around? We (PI: Jennifer Johnson (Ohio State) with Beers, Christlieb, and myself) are trying to find out where the NEMP stars are and why we don't see more. Jennifer obtained data from several runs at Kitt Peak and CTIO.

MIRIAD

Spitzer MIPS IR imaging of dust shells around evolved AGB stars. (MIRIAD), GOP 20258, 2005, PI: Angela Speck (University of Missouri). First data taken, first models computed ...

Other

I am involved in a radial velocity campaign of EMP stars (PI: Sara Lucatello) using the VLT, as well as with projects using HST and XMM-Newton (PI: Klaus Werner).
Falk Herwig, Last update: Thu 19 Jan 2017 07:22:25 PST , WWW home