Farewell to KITP Massive Stars May 31 2017, 14:21

Earlier this month I returned from the Massive Stars program at the Kavli Institute for Theoretical Physics. Speaking personally, the program was a huge success; I met many awesome people, got involved in a number of new projects, and decided that I Rather Like the West Coast! Here's a sample of some of the papers which will emerge from this incredible experience:

• Angular momentum transport by heat-driven g-modes in slowly pulsating B stars (with Jacqueline Goldstein and Ellen Zweibel; submitted to MNRAS)
• The Tayler Instability in the Anelastic Approximation (with Jacqueline Goldstein and Ellen Zweibel; to be submitted to MNRAS)
• Super-Eddington stellar winds: unifying radiative-enthalpy vs. flux-driven models (with Stan Owocki and Eliot Quataert; to be submitted to MNRAS)
• A paper on pulsation instabilities in supersoft sources (with Bill Wolf and Lars Bildsten; in preparation)
• A paper on new MESA capabilities (with Anne Thoul and the rest of the MESA team; in preparation)

Now that I'm back in Madison, I'm scrambling to get all these papers out the door — and to push ahead with releasing version 5.0 of GYRE, which is long overdue.

Massive stars come to KITP Feb 26 2017, 18:52

I'm out in Santa Barbara for the next 11 weeks, helping to organize (and participate in) the Massive Stars program occurring at the Kavli Institute for Theoretical Physics. I'm hoping this time away from Madison will give me a chance to reboot mad star and write about some of the cool stuff I've been working on over the past couple of years.

In addition to meeting and working with some of the world's greatest stellar astrophysicists (including my old boss and buddy Stan Owocki), I hope to achieve at least some of the following goals:

• Finish writing the new user guide for GYRE, so I can finally get release 5.0 officially out of the door.
• Create new releases of the MESA SDK (and Mad SDK), amongst other things bringing the gfortran compiler up to date.
• Get my YARG code working again, so I can finish up a project on massive star wind polarization that I started years ago with Nick Mast (now a grad student at Minnesota).
• Complete a too-long-in-the-works paper with Jacqueline Goldstein and Ellen Zweibel, demonstrating that heat-driven g modes can rapidly alter the internal rotation profiles of slowly pulsating B stars.
• Hang out with Bill Paxton (the living one, not the sadly departed one) and other MESA developers, to work on the next release of the code.

By the way, the picture is a jar of my double-trouble habanero jelly. I made a batch last week, and brought it with me. One jar is promised to Frank Timmes, the others will likely be used (in anger!) as prizes for program participants.

Weekly Update Sep 2 2016, 07:36

I've let madstar lapse for a while. What have I been up to? Here's an update of my activity for the week ending September 2, 2016:

• Re-worked simulations of wave angular momentum in slowly-pulsating B (SPB) stars. Originally, I was appyling the wave torque through a prescribed dOmega/dt. However, if the moment of inertia of the star changes during the torquing process, then it's not guaranteed that the total angular momentum of the star remain zero (as it should, for wave transport). So, it's better to apply the torque through a prescribed dj/dt — and that's what I'm doing, using MESA's other_torque hook. Hopefully, this is the final tweak to the simulations, and I can get the project written up quickly.

• Cooked up and canned batches of sungold tomato relish (recipe here) and habanero/ghost pepper jelly (recipe here; replace jalapeños with habaneros, one ghost pepper and yellow bell peppers). Both damn tasty!

• Visited the Learning Games Network on Science Drive, to discuss the upcoming test of their At Play in the Cosmos game. I'm teaching two sections of Astronomy 103 this semester (400 students total), and we'll be trying out the game as a tool to learn introductory astronomy.

New MESA movies Oct 8 2013, 09:06

Yesterday I uploaded a new set of stellar evolution movies, based on models calculated using MESA. Although still a work-in-progress, these are a big improvement on my old EZ-Web movies, and I hope eventually to build up a complete library showing stars' evolution from cradle to grave.

Dispatches from the Code Front Sep 19 2013, 10:41

I thought I'd post some news on the code development front. So, in brief:

• GYRE is now up to version 2.1.1. A recent improvements is the ability to write text-format output files (by popular demand from MESA Summer School participants!).
• The instrument paper discussing GYRE (Townsend & Teitler 2013) is working its way through MNRAS's publication system. It should be out in a week or two; a preprint is available here.
• The MESA Software Development Kit has seen a few recent updates, which address missing library issues on Linux platforms.
• Nick Hill has a cool working prototype of a code suite for doing spectroscopic modeling on GPUs. This incorporates the GRASSY spectral synthesis code I've been working on, plus the new GLaDOS code Nick wrote, which uses OpenGL to model astrophysical surfaces (e.g., stellar photospheres).
• Chris Bard is making excellent progress on a new arbitrary-field rigid field hydrodynamics (ARFHD) code, and we should be seeing results soon. The code is a generalization of the RFHD code described in Townsend et al. (2007) to allow non-dipole field topologies.
• EZ-Web now supports writing output files in CGS units rather than the usual SI units (much to the relief of Astronomers everywhere!).