Pulsational (L/M threshold) mass loss and new angular momentum loss prescription

online-docs/pages/User guide/Program options/program-options-list-defaults.rst

@@ -207,6 +207,15 @@ Default = ZERO
 Recombination energy density (erg g−1). |br|
 Default = :math:`1.5 \times 10^{13}`
 
+**common-envelope-second-stage-beta** |br|
+The fraction of the mass lost during the second stage of a 2-stage common envelope that is accreted. |br|
+Default = 0
+
+**--common-envelope-second-stage-gamma-prescription** |br|
+The specific angular momentum prescription for mass lost during the second stage of a 2-stage common envelope event. |br|
+Options: { JEANS, ISOTROPIC, CIRCUMBINARY, KLENCKI_LINEAR, MACLEOD_LINEAR, ARBITRARY, MIN } |br|
+Default = ISOTROPIC
+
 **--common-envelope-slope-kruckow** |br|
 Slope for the Kruckow lambda (see Kruckow et al. 2016 as implemented by Vigna-Gomez et al. 2018). |br|
 Default = −0.833333
@@ -894,7 +903,7 @@ Default = THERMAL
 
 **--mass-transfer-angular-momentum-loss-prescription** |br|
 Mass Transfer Angular Momentum Loss prescription. |br|
-Options: { JEANS, ISOTROPIC, CIRCUMBINARY, KLENCKI_LINEAR, MACLEOD_LINEAR, ARBITRARY } |br|
+Options: { JEANS, ISOTROPIC, CIRCUMBINARY, KLENCKI_LINEAR, MACLEOD_LINEAR, ARBITRARY, MIN } |br|
 Default = ISOTROPIC
 
 **--mass-transfer-fa** |br|
@@ -1571,7 +1580,7 @@ Go to :ref:`the top of this page <options-props-top>` for the full alphabetical
 --common-envelope-lambda-nanjing-use_rejuvenated-mass, --common-envelope-allow-main-sequence-survive, --common-envelope-allow-radiative-envelope-survive, 
 --common-envelope-allow-immediate-RLOF-post-CE-survive, --common-envelope-mass-accretion-prescription, --common-envelope-mass-accretion-constant, 
 --common-envelope-mass-accretion-min, --common-envelope-mass-accretion-max, --common-envelope-recombination-energy-density, --maximum-mass-donor-nandez-ivanova, 
---revised-energy-formalism-nandez-ivanova
+--revised-energy-formalism-nandez-ivanova, common-envelope-second-stage-beta, common-envelope-second-stage-gamma-prescription
 
 :ref:`Back to Top <options-props-top>`
 

src/BaseBinaryStar.cpp

@@ -1864,6 +1864,8 @@ double BaseBinaryStar::CalculateGammaAngularMomentumLoss_Static(const double p_D
         case MT_ANGULAR_MOMENTUM_LOSS_PRESCRIPTION::JEANS                : gamma = p_AccretorMass / p_DonorMass; break;             // vicinity of the donor 
 
         case MT_ANGULAR_MOMENTUM_LOSS_PRESCRIPTION::ISOTROPIC_RE_EMISSION: gamma = p_DonorMass / p_AccretorMass; break;             // vicinity of the accretor
+
+        case MT_ANGULAR_MOMENTUM_LOSS_PRESCRIPTION::MIN:                   gamma = std::min(p_AccretorMass / p_DonorMass, p_DonorMass / p_AccretorMass); break; // the smaller of isotropic re-emission and Jeans mode mass loss
 
         case MT_ANGULAR_MOMENTUM_LOSS_PRESCRIPTION::ARBITRARY            : gamma = OPTIONS->MassTransferJloss(); break;
 
@@ -2179,6 +2181,15 @@ void BaseBinaryStar::CalculateMassTransfer(const double p_Dt) {
                 massDiffDonor     = -envMassDonor;
                 isEnvelopeRemoved = true;
             }
+            if (m_MassTransferTimescale == MT_TIMESCALE::THERMAL && OPTIONS->ExpelConvectiveEnvelopeAboveLuminosityThreshold() && m_Donor->DetermineEnvelopeType() == ENVELOPE::CONVECTIVE) {
+                // check if pulsations remove envelope in the middle of mass transfer; if so, only remove envelope up to that point during mass transfer, leave pulsation itself to next time step
+                double massPulsation    = m_Donor->Luminosity() / PPOW(10.0, OPTIONS->LuminosityToMassThreshold());     // mass at which the pulsation threshold would be passed, log_10 (L/M) = LuminosityToMassThreshold, assumes unchanged L
+                if(massPulsation > m_Donor->CoreMass()) {
+                    massDiffDonor = massPulsation - m_Donor->Mass();
+                    isEnvelopeRemoved = false;
+                }
+            }
+
             else
                 massDiffDonor = -massDiffDonor;                                                                                 // set mass difference
         }
@@ -2626,7 +2637,7 @@ void BaseBinaryStar::ResolveMassChanges() {
     // assume the entire envelope was lost on timescales long relative to the orbit
     if (m_Star1->EnvelopeJustExpelledByPulsations() || m_Star2->EnvelopeJustExpelledByPulsations()) {
         // update separation in response to pulsational mass loss
-        m_SemiMajorAxis /= (2.0 - ((m_Star1->MassPrev() + m_Star2->MassPrev()) / (m_Star1->Mass() + m_Star2->Mass())));
+        m_SemiMajorAxis *= ((m_Star1->MassPrev() + m_Star2->MassPrev()) / (m_Star1->Mass() + m_Star2->Mass())); // conserve a*M
         m_Star1->ResetEnvelopeExpulsationByPulsations();
         m_Star2->ResetEnvelopeExpulsationByPulsations();
     }

src/changelog.h

@@ -1703,10 +1703,15 @@
 //                                          - Fixed HeSDs not being recorded in the Supernovae logs (mentioned in issue 1350).
 //  03.29.04  IM - April 19, 2026       - Enhancement:
 //                                          - Corrected the M&M NS remnant mass prescription to never return a remnant mass larger than the CO core mass (see issue #1468)
-//  03.29.05  AG - May 26, 2026          - Defect repair:
-//                                       - Fix for generalized issue #1378: reinstate "false" fallback option for SN kick angle options (mistakenly changed to "true" in v03.00.00)
+//  03.29.05  AG - May 26, 2026         - Defect repair:
+//                                          - Fix for generalized issue #1378: reinstate "false" fallback option for SN kick angle options (mistakenly changed to "true" in v03.00.00)
 //  03.29.06  DH - September 23, 2026    - Defect repair:
 //                                       - Fix for issue #1484: reversed interpolation factors for mass transfer stability with Ge's model q_crit, in MainSequence and HeMS
+//  03.30.00  IM - Sep 23, 2026         - Enhancement:
+//                                          - Include the possibility of pulsational (L/M threshold) mass loss in the middle of a thermal-timescale mass transfer episode that removes entire envelope
+//                                          - Add option (MIN) to lose specific angular momentum during non-conservative mass transfer that is the smaller of isotropic re-emission and Jeans mode mass loss
+//                                      - Defect repair:
+//                                          - Corrected orbital separation re-computation following pulsational (L/M threshold) mass loss
 //
 // Version string format is MM.mm.rr, where
 //
@@ -1717,7 +1722,7 @@
 // if MM is incremented, set mm and rr to 00, even if defect repairs and minor enhancements were also made
 // if mm is incremented, set rr to 00, even if defect repairs were also made
 
-const std::string VERSION_STRING = "03.29.06";
+const std::string VERSION_STRING = "03.30.00";
 
 
 # endif // __changelog_h__

src/typedefs.h

@@ -651,14 +651,15 @@ const COMPASUnorderedMap<MT_ACCRETION_EFFICIENCY_PRESCRIPTION, std::string> MT_A
 };
 
 // mass transfer angular momentum loss prescriptions
-enum class MT_ANGULAR_MOMENTUM_LOSS_PRESCRIPTION: int { JEANS, ISOTROPIC_RE_EMISSION, CIRCUMBINARY_RING, MACLEOD_LINEAR, KLENCKI_LINEAR, ARBITRARY };
+enum class MT_ANGULAR_MOMENTUM_LOSS_PRESCRIPTION: int { JEANS, ISOTROPIC_RE_EMISSION, CIRCUMBINARY_RING, MACLEOD_LINEAR, KLENCKI_LINEAR, ARBITRARY, MIN };
 const COMPASUnorderedMap<MT_ANGULAR_MOMENTUM_LOSS_PRESCRIPTION, std::string> MT_ANGULAR_MOMENTUM_LOSS_PRESCRIPTION_LABEL = {
     { MT_ANGULAR_MOMENTUM_LOSS_PRESCRIPTION::JEANS,                 "JEANS" },
     { MT_ANGULAR_MOMENTUM_LOSS_PRESCRIPTION::ISOTROPIC_RE_EMISSION, "ISOTROPIC" },
     { MT_ANGULAR_MOMENTUM_LOSS_PRESCRIPTION::CIRCUMBINARY_RING,     "CIRCUMBINARY" },
     { MT_ANGULAR_MOMENTUM_LOSS_PRESCRIPTION::MACLEOD_LINEAR,        "MACLEOD_LINEAR" },
     { MT_ANGULAR_MOMENTUM_LOSS_PRESCRIPTION::KLENCKI_LINEAR,        "KLENCKI_LINEAR" },
-    { MT_ANGULAR_MOMENTUM_LOSS_PRESCRIPTION::ARBITRARY,             "ARBITRARY" }
+    { MT_ANGULAR_MOMENTUM_LOSS_PRESCRIPTION::ARBITRARY,             "ARBITRARY" },
+    { MT_ANGULAR_MOMENTUM_LOSS_PRESCRIPTION::MIN,                   "MIN" }
 };
 
 // mass transfer cases