Supernova step.

This step models the end of life of stars by being applied to a binary object and verifying its state. It performs the collapse prescription used to initialize the step in the respective star. Depending on the C and He cores the final state of the star is determined, from the formation of white dwarfs to electron-capture supernova, Fe core-collapse supernova, pair pulsation supernova and pair instability supernova.

class posydon.binary_evol.SN.step_SN.Couch20_corecollapse(turbulence_strength, path_engine_dataset, verbose)[source]

Bases: object

Compute SN final remnant mass, fallback fraction and stellar state.

This considers the nearest neighboor of the He core mass of the star, previous to the collapse. Considering a set of data for which the He core mass of the compact object progenitors before the collapse, the final remnant mass and final stellar state of the compact object is known.

Parameters

  • engine (string) – Engine for the supernova explosion, from the one where used in [1].

  • path_engine_dataset (string) – Path to the location of the data on initial and final states for each engine described in Sukhbold et al. 2016

Returns

  • m_rem (double) – Remnant mass of the compact object in M_sun.

  • f_fb (double) – Fallback mass of the compact object in M_sun.

  • state (string) – Finall state of the stellar remnant after the supernova.

References

1

Sukhbold, T., Ertl, T., Woosley, S. E., Brown, J. M., & Janka,

H. T. (2016). Core-collapse supernovae from 9 to 120 solar masses based on neutrino-powered explosions. The Astrophysical Journal, 821(1), 38. .. [2] Couch, S. M., Warren, M. L., & O’Connor, E. P. 2020, ApJ, 890, 127 Simulating Turbulence-aided Neutrino-driven Core-collapse Supernova Explosions in One Dimension

Initialize a Couch20_corecollapse instance.

class posydon.binary_evol.SN.step_SN.StepSN(mechanism='Patton&Sukhbold20-engine', engine='N20', PISN='Marchant+19', ECSN='Podsiadlowksi+04', max_neutrino_mass_loss=0.5, kick=True, kick_normalisation='one_over_mass', sigma_kick_CCSN_NS=265.0, sigma_kick_CCSN_BH=265.0, sigma_kick_ECSN=20.0, max_NS_mass=2.5, use_interp_values=True, use_profiles=True, use_core_masses=True, approx_at_he_depletion=False, verbose=False, **kwargs)[source]

Bases: object

The supernova step in POSYDON.

Keyword Arguments

  • mechanism (str) –

    Mechanism to perform the core-collapse on the star object and predict the supernova remnant outcome. Available options are:

    • ’Fryer+12-rapid’ : The rapid supernova-engine described in

    [1]

    • ’Fryer+12-delayed’ : The delayed supernova-engine described in

    [1]

    • ’direct’ : The pre-supernova mass of the starr is collapsed into the

    remnant baryonic mass.

    • ’direct_he_core’ : The pre-supernova He core mass of the starr is

    collapsed into the remnant baryonic mass.

    • ’Sukhbold+16-engine’ : Uses the results from [2]

    to describe the collapse of the star.

    • ’Patton&Sukhbold20-engine’: Uses the results from [5]

    to describe the collapse of the star.

    • ’Couch+20-engine’: Uses the results from [6]

    to describe the collapse of the star.

  • engine (str) –

    Engine used for supernova remnanrt outcome propierties for the Sukhbold+16-engineand and Patton&Sukhbold20-engine mechanisms. Available options:

    • ’N20’

  • PISN (str) –

    Prescrition to take on the pair-instability supernova. Avialable options:

    • ’Marchant+19’ : Descripes the pair-instability supernova as

    [3].

  • mass_central_BH (double) – Central mass collapsed automatically on black-holes formed by direct collapse.

  • max_neutrino_mass_loss (double) – Neutrino mass loss during the collapse of the proto neutron-star.

  • kick (bool) – If True, the kick velocities are computed corresponding to the supernova event, else no kicks are taking into account for any supernova outcome.

  • kick_normalisation (str) – Renormalise the kick by: ‘one_minus_fallback’ : (1-f_fb) ‘one_over_mass’ : 1.4/m_BH ‘zero’ : 0. ‘one’ : 1. ‘NS_one_minus_fallback_BH_one’: 1 for BH, (1-f_fb) for NS

  • ECSN (str) –

    Prescription to determine the production of an electron-capture supernova. Avialable options:

    • ’Tauris+15’: Determines the electron capture supernova in terms

    of the CO core mass at pre-supernova, taking the limits from [4].

  • sigma_kick_CCSN_NS (double) – Standard deviation for a Maxwellian distribution to compute the kick velocities from NSs formed by Fe core-collapse supernova.

  • sigma_kick_CCSN_BH (double) – Standard deviation for a Maxwellian distribution to compute the kick velocities from BHs formed by Fe core-collapse supernova.

  • sigma_kick_ECSN (double) – Standard deviation for a Maxwellian distribution to compute the kick velocities from compact-object formed by electron-capture supernova.

  • max_NS_mass (double) – Maximum neutron-star mass.

  • use_interp_values (bool) – The outcome of core collpase was interpolated from a post processed MESA grid and stored in the star object in the mesa_step or detached_step (default). This option supports only default assumptions for all core collase mechanism.

  • use_profiles (bool) – Perfrome the core collpase given a MESA profile. To use this option a MESA profile must be stored in the star object which is provided by nearest neighbor interpolation in the mesa_step or (TODO) interpolated in the detached_step.

  • use_core_masses (bool) – This option uses the core masses at carbon depletion to determine the core collapse outcoume (classical population sythesis threatment).

  • approx_at_he_depletion (bool) – This option is relevant only for the mechanism Patton&Sukhbold20-engine. In case the core masses at he-depletion are not present in the star object, compute them from the history, else (approximation=True) approximate it from the core masses at C depletion.

  • verbose (bool) – If True, the messages will be prited in the console.

References

1

Fryer, C. L., Belczynski, K., Wiktorowicz, G., Dominik, M.,

Kalogera, V., & Holz, D. E. (2012). Compact remnant mass function: dependence on the explosion mechanism and metallicity. The Astrophysical Journal, 749(1), 91.

2

Sukhbold, T., Ertl, T., Woosley, S. E., Brown, J. M., & Janka,

H. T. (2016). Core-collapse supernovae from 9 to 120 solar masses based on neutrino-powered explosions. The Astrophysical Journal, 821(1), 38.

3

Marchant, P., Renzo, M., Farmer, R., Pappas, K. M., Taam, R. E.,

De Mink, S. E., & Kalogera, V. (2019). Pulsational pair-instability supernovae in very close binaries. The Astrophysical Journal, 882(1), 36.

4

Tauris, T. M., Langer, N., & Podsiadlowski, P. (2015).

Ultra-stripped supernovae: progenitors and fate. Monthly Notices of the Royal Astronomical Society, 451(2), 2123-2144.

..[5] Patton, R. A. & Sukhbold, T. 2020, MNRAS, 499, 2803. Towards a realistic explosion landscape for binary population synthesis

..[6] Couch, S. M., Warren, M. L., & O’Connor, E. P. 2020, ApJ, 890, 127. Simulating Turbulence-aided Neutrino-driven Core-collapse Supernova Explosions in One Dimension

Initialize a StepSN instance.

C_abundance_for_H_stars(CO_core_mass)[source]

Get the C abundance for a H-star given it’s CO core mass.

C_abundance_for_He_stars(CO_core_mass)[source]

Get the C abundance for a He-star given it’s CO core mass.

PISN_prescription(star)[source]

Compute baryonic remnant mass for the PPISN and PISN prescription.

Parameters

star (object) – Star object containing the star properties.

Returns

m_PISN – Maximum stellar mass in M_sun after the PPISN/PISN prescription.

Return type

double

Patton20_corecollapse(star, engine)[source]

Compute supernova final remnant mass and fallback fraction.

It uses the results from [1]. The prediction for the core-collapse outcome is performed using the C core mass and its C abundance. The criterion by [2] is used to determine the final outcome.

Parameters

star (obj) – Star object of a collapsing star containing the MESA profile.

Returns

  • m_rem (double) – Remnant mass of the compact object in M_sun.

  • f_fb (double) – Fallback mass of the compact object in M_sun.

References

1

Patton, R. A., & Sukhbold, T. (2020). MNRAS, 499(2), 2803-2816.

2

Ertl, T., Janka, H. T., Woosley, S. E., Sukhbold, T., & Ugliano, M. (2016). ApJ, 818(2), 124.

check()[source]

Check the internal integrity and the values of the parameters.

check_SN_type(m_core, m_He_core, m_star)[source]

Get the remnant mass, fallback frac., state & SN type of the SN.

collapse_star(star)[source]

Collapse the star object into a compact object.

This routine supports three options: 1. use_interp_values : True

The outcome of core collpase was interpolated from a post processed MESA grid and stored in the star object in the mesa_step or detached_step (default). This option supports only default assumptions for all core collase mechanism.

  1. use_profiles : False Perfrome the core collpase given a MESA profile. To use this option a MESA profile must be stored in the star object which is provided by nearest neighbor interpolation in the mesa_step or (TODO) interpolated in the detached_step.

  2. use_core_masses : False This option uses the core masses at carbon depletion to determine the core collapse outcoume (classical population sythesis threatment).

Parameters

star (object) – Star object containing the star properties.

Returns

  • m_rem (double) – Remnant mass of the compact object in M_sun. This quantity accounts for the mass loss thorugh neutrino.

  • state (string) – New state of the star object.

compute_m_rembar(star, m_PISN)[source]

Compute supernova remnant barionic mass.

We follow the selected electron-capture and core-collapse mechanisms to get the remnant baryonic mass.

Parameters

  • star (object) – Star object containing the star properties.

  • m_PISN (double) – Maximum stellar mass in M_sun after the PPISN/PISN prescription.

Returns

  • m_rembar (double) – Barioninc mass of the remnant after the supernova in M_sun. This quantity does NOT take into account any neutrino lost, this will be taken into account in collapse_star().

  • f_fb (double) – Mass fraction falling back onto the compact object created in the supernova. The maximum value is 1 and means that all the barionic mass is collapsing to form the compact object.

  • state (string) – Finall state of the stellar remnant after the supernova.

generate_kick(star, sigma)[source]

Draw a kick from a Maxwellian distribution.

We follow Hobbs G., Lorimer D. R., Lyne A. G., Kramer M., 2005, MNRAS, 360, 974 and choose sigma = 265 km/s

We rescale the kicks by 1 - f_fb as in Eq. 21 of Fryer, C. L., Belczynski, K., Wiktorowicz, G., Dominik, M., Kalogera, V., & Holz, D. E. (2012), ApJ, 749(1), 91.

Parameters

star (object) – Star object containing the star properties.

Returns

Vkick – Natal orbital kick in km/s.

Return type

double

get_CO_core_params(star, approximation=False)[source]

Get the CO core mass and C abundance at the pre-supernova phase.

If the two parameters are available in the star’s profile, perform the Patton&Sukhbold,20 core-collapse.

If the CO core mass is available but not the C abundance then the latter is computed from the formulas at Patton&Sukhbold,20.

Parameters
starobj

Star object of a collapsing star containing the MESA profile.

approximationbool

In case the core masses at he-depletion are not present in the star object, compute them from the history default behaviour, else (approximation=True) approximate it from the core masses at C depletion.

CO_core_massfloat

Mass of the CO core at He depletion == C core ignition.

C_core_abundancefloat

C abundance of the CO core He depletion == C core ignition.

get_M4_mu4_Patton20(CO_core_mass, C_core_abundance)[source]

Get the M4 and mu4 using Patton+20.

orbital_kick(binary)[source]

Do the orbital kick.

This function computes the supernova step of the binary object. It checks which binary_state riched the core collapse flag, either CC1 or CC2, and run the step accordingly updating the binary object.

Geometry: The collapsing helium star, here M_he_star, lies on the origin of the coordinate system moving in direction of positive y axis. The companion, here M_companion, lies on the negative X axis and Z-axis completes right-handed coordinate system. See Fig 1 in Kalogera 1996 for a coordinate system drawing.

phi :

Angle between z-axis and projection of kick onto x-z plane.

theta :

Angle between pre- supernova star velocity relative to the companion (i.e. along the positive y axis) and the kick velocity.

tilt :

The angle between pre- and post- supenova orbial planes. This is equal to the angle between the relative velocity of the helium star to the companion just before the explosion (see Vr) and the projection of the relative velocy just after the explosion onto the y-z plane.

mean_anomaly:

is the mean anomaly, i.e the fraction of an elliptical orbit’s period that has elapsed since the orbiting body passed periapsis, expressed as an angle.

Parameters

binary (object) – Binary object containing the binary properties and the two star objects.

References

1

Kalogera, V. 1996, ApJ, 471, 352

2

Wong, T.-W., Valsecchi, F., Fragos, T., & Kalogera, V. 2012, ApJ, 747, 111

class posydon.binary_evol.SN.step_SN.Sukhbold16_corecollapse(engine, path_engine_dataset, verbose)[source]

Bases: object

Compute supernova final remnant mass, fallback fraction and CO type.

This consider the nearest neighboor of the He core mass of the star, previous to the collapse. Considering a set of data for which the He core mass of the compact object projenitos previous the collapse, the final remnant mass and final stellar state of the compact object is known.

Parameters

  • engine (string) – Engine for the supernova explosion, from the one where used in [1].

  • path_engine_dataset (string) – Path to the location of the data on initial and final states for each engine described in Sukhbold et al. 2016

Returns

  • m_rem (double) – Remnant mass of the compact object in M_sun.

  • f_fb (double) – Fallback mass of the compact object in M_sun.

  • state (string) – Finall state of the stellar remnant after the supernova.

References

1

Sukhbold, T., Ertl, T., Woosley, S. E., Brown, J. M., & Janka,

H. T. (2016). Core-collapse supernovae from 9 to 120 solar masses based on neutrino-powered explosions. The Astrophysical Journal, 821(1), 38.

Initialize a Sukhbold16_corecollapse instance.