.. _mesa-web-intro: *************************** 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 ``_ * 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.