Glossary

Stellar types

Acronym	Stellar phase
MS	Main Sequence
HG	Hertzsprung Gap
RGB	Red Giant Branch
cHeB	Core Helium Burning
AGB	Asymptotic Giant Branch
TPAGB	Thermally Pulsing Asymptotic Giant Branch
He-MS	Helium Main Sequence (naked helium stars only)
He-HG	Helium Hertzsprung Gap (naked helium stars only)
He-GB	Helium Giant Branch (naked helium stars only)

SSE-style file

Important

These files can only be created in the standalone mode of METISSE.

METISSE can produce two types of output files, one of them are SSE-style files. SSE-style output files are text files ending with .dat and are controlled by the write_output_to_file function in SSE_input_controls. These files have a file structure similar to the popular SSE code. They contain the below listed stellar parameters up to the maximum age. Time and age at hydrogen ZAMS are assumed to be zero at the beginning of the code.

Column Header	Description
time	Physical time [Myr]
age	Age of star [Myr]
mass	Current mass of the star [M]
core_mass	Mass of dominant core [M]
He_core	Mass of helium core [M]
CO_core	Mass of carbon-oxygen core [M]
log_L	Log of surface luminosity [L]
log_Teff	Log of effective temperature [K]
log_radius	Log of radius [R]
phase	SSE stellar type/phase

MIST-style file

MIST-style files, which end with .eep, are produced for debugging purposes. The file structure follows the same format used in the files from the MIST project. METISSE can write a mass-interpolated track to an output file with the same columns as input files, including a stellar phase column. This output file only contains data from ZAMS to the end of the nuclear-burning phases and does not include information about the remnant phase. It is controlled by the write_eep_file function in METISSE_input_controls.

Metallicity File

This file ends with _metallicity.inand contains information about the input tracks for a specific metallicity, including the path to the folder containing the EEP tracks, the metallicity value, and other relevant information and metadata. For more details see Metallicity controls.

Format files

The format file contains information on how to read files, such as header location, important EEPs, and certain column names. The path to a format file is provided through the metallicity file. For more details see Format controls.

Fortran namelists

Namelists offer a convenient method for inputting data into Fortran programs. Each entry within a namelist follows this structure:

name = value ! comment

Values are provided using typical Fortran syntax. SSE_input_controls, METISSE_input_controls, metallicity_controls and format_controls are Fortran namelists, so comments (anything after the exclamation mark symbol!) and whitespaces can be used freely. Characters are also case-insensitive. It is important to ensure that there is a blank line at the end of the file following the / symbol.

Note

Never modify any file directly inside the defaults folder.

Stellar tracks and stellar models

A stellar model represents the physical parameters of a star at a specific point in time. By calculating a series of stellar models from the star’s formation to the end of its nuclear-burning phase, we can determine the evolutionary history of the star, also known as its stellar track. In this documentation, we use “stellar track” to refer to a time sequence of stellar models. In contrast “set of stellar models” or “set of stellar tracks” refers to the evolutionary tracks of stars with different initial masses but the same metallicity.