The SingleStar object

The Single Star object contains the current and past states of the star. Only parameters in the STARPROPERTIES list are stored in the history. The current parameter value of the star object is accessed as, e.g. star.mass while its past history with star.mass_history.

To use SingleStar object import it using:

from posydon.binary_evol.singlestar import SingleStar

Creating a SingleStar object

STARPROPERTIES

The star properties are defined as follows

STARPROPERTIES

Properties	Descriptions
state	The state of the star, see state options.
metallicity	Fractional metal content (Z) of the star.
mass	Stellar mass in M_sun.
log_R	log10 stellar radius in R_sun.
log_L	log10 surface stellar luminosity in L_sun.
mdot	Stellar mass-loss rate in Msun/yr.
lg_wind_mdot	log10 stellar wind mass-loss rate in Msun/yr.
he_core_mass	Helium core mass in M_sun.
he_core_radius	Helium core radius in R_sun.
c_core_mass	Carbon core mass in M_sun.
c_core_radius	Carbon core mass in M_sun.
o_core_mass	Oxygen core mass in M_sun.
o_core_radius	Oxygen core radius in R_sun.
center_h1	Hydrogen central mass fraction abundance.
center_he4	Helium central mass fraction abundance.
center_c12	Carbon central mass fraction abundance.
center_n14	Nitrogen central mass fraction abundance.
center_o16	Oxygen central mass fraction abundance.
surface_h1	Hydrogen surface mass fraction abundance.
surface_he4	Helium surface mass fraction abundance.
surface_c12	Carbon surface mass fraction abundance.
surface_n14	Nitrogen surface mass fraction abundance.
surface_o16	Oxygen surface mass fraction abundance.
log_LH	log10 total thermal power from PP and CNO, excluding neutrinos devided by L_sun.
log_LHe	log10 total thermal power from triple-alpha, excluding neutrinos devided by L_sun.
log_LZ	log10 total burning power excluding LH and LHe and photodisintegrations devided by L_sun.
log_Lnuc	log10 total nuclear reaction luminosity (LH + LHe LZ) in L_sun.
c12_c12	log10 total luminosity for c12_c12 reaction in L_sun.
surf_avg_omega_div_omega_crit	Average surface omega divided by critical omega.
total_moment_of_inertia	Total moment of inertia in g*cm^2.
log_total_angular_momentum	log10 total angular momentum of the star g*cm^2*s^-1
spin	Angular momentum of the star in g*cm^2*s^-1 or dimensionless BH spin.
profile	Stellar profile from MESA. [not current supported for the initial-final interpolator]

Additional scalar properties are added during the evolution depending on which steps the star has undergone. These properties are not stored in the history.

TODO: add missing properties

State options

Star states are defined on their relative position on the HR diagram as follows:

State

State	Description
PreMS	The star is on the pre-main-sequence phase.
MS	The star is in the Main Sequence phase.
PostMS	The star is in the post Main Sequence phase.
HeMS	The star is at the beginning of the He burning phase.
PostHeMS	The star is evolving through the beginning of the He burning phase.
WD	The star is a White Dwarf.
NS	The star is a Neutron Star.
BH	The star is a Black Hole.

TODO: update the states to POSYDON v2.0.0

Basic example

The simplest method is to provide kwargs of the initial stellar parameters.

kwargs = {'state' : 'MS',
          'mass' : 10.0,
          'metallicity' : 0.014}
SingleStar(**kwargs)

Now, the SingleStar object is ready to be used.