Intemission: MESA-Web Intro

Overview

What is MESA?

MESA (Modules for Experiments in Stellar Astrophysics) is a stellar evolution code — a sophisticated piece of software for simulating the structure and evolution of stars on computers. It is developed by a team of researchers (including Rich) under an open-source license, meaning that anyone can use it for free and modify it as their needs dictate. Currently, MESA is in use by more than 1,000 scientists worldwide (see here for a map of where they are); Rich uses it extensively when creating stellar models for analysis in his handouts.

What is MESA-Web?

Installing and running MESA isn’t a straightforward task; its a complex piece of software, and requires a fair bit of computer expertise to use (see here if you want to try it yourself!). Accordingly, to help new users get acquainted with MESA, Frank Timmes and Carl Fields (at Arizona State University) created a web-based interface to MESA, called MESA-Web. This interface allows you to set up various parameters (e.g., the stellar mass) and then submit a calculation to a computer running MESA.

A First Calculation

To run your first MESA-Web calculation, follow these steps:

  • Visit the MESA-Web page at http://mesa-web.asu.edu/

  • Set the Initial Mass field to 1.0 (i.e., a model for the Sun)

  • Change the Variance Control Target parameter (in the Temporal (Time) Resolution - Global section) to 1d-3

  • Change the Quantity parameter (in the Custom Stopping Condition section) to max age (in years)

  • Change the Value field (in the Custom Stopping Condition section) to 2e10

  • Enter a valid email address in the Email Address field

  • Press the submit button, and cross your fingers!

It will take a day or two for the calculation to complete. When it does, you’ll receive an email containing a link to a Zip archive. Download this Zip archive and unpack it into the astro_310 folder you created after installing Anaconda.