GLOBAL KNOWLEDGE ARK

Reference library

Foundations

Explore concepts, laws, equations and methods, with clear explanations of their use and sources. Choose an area of study or find a specific entry.

More filters

Reference entries

Showing 1021–1050 of 1709 reference entries

Earth & cosmosStellar radial velocity and companion-mass inference

In a Newtonian isolated two-body Keplerian model, the host star's line-of-sight orbital velocity has semi-amplitude K=(2πG/P)^(1/3) Mp sin i/[(Mstar+Mp)^(2/3)√(1−e²)].

MethodEarth & cosmosInitial mass functions and stellar population accounting

For a specified birth population, an initial mass function ξ(m) defines dN=ξ(m)dm on a stated initial-mass interval.

DefinitionEarth & cosmosWhite-dwarf mass–radius relation and ideal limiting mass

Cold noninteracting electron support and spherical Newtonian hydrostatic balance give a nonrelativistic n=3/2 polytrope with R proportional to μₑ^(−5/3)M^(−1/3).

ModelEarth & cosmosRotation-powered pulsars and spin-down inference

Neutron-star pulsars have rotating magnetized stellar remnants whose emission can sweep past the observer.

ModelEarth & cosmosCore collapse and thermonuclear stellar explosions

Core-collapse supernovae involve loss of support in an evolved stellar core, rapid contraction and an explosion whose energy transfer involves dense matter and neutrinos.

ModelEarth & cosmosAccretion energy, efficiency and angular-momentum transport

Matter moving inward in a gravitational field can release binding energy if energy is dissipated.

ModelEarth & cosmosEddington luminosity as a conditional force balance

For isotropic luminosity L and a constant flux-weighted opacity per mass κ, outward radiative acceleration is κL/(4πr²c).

ModelEarth & cosmosRoche geometry and binary mass transfer

In a circular two-point-mass binary's corotating frame, the effective potential per mass is Φ_eff=−GM₁/r₁−GM₂/r₂−Ω²(x²+y²)/2, with origin at the barycentre and Ω²=G(M₁+M₂)/a³.

ModelEarth & cosmosAccretion-powered galactic nuclei and observational inference

Active galactic nuclei can radiate strongly as matter accretes around a central supermassive black hole.

ModelEarth & cosmosPrimordial nuclear freeze-out and the deuterium bottleneck

In hot Big-Bang nucleosynthesis, neutron–proton conversion initially approaches chemical equilibrium.

ModelEarth & cosmosRecombination, last scattering and reionization

Atomic recombination binds many previously free electrons and lowers photon-scattering opacity.

ModelEarth & cosmosIonized hydrogen regions and the Strömgren photon budget

An ionization-bounded pure-hydrogen region in steady balance equates absorbed external ionizing photons to net recombinations: Q_H=∫α_B nₑnₚ dV.

ModelEarth & cosmosJeans instability of a local gas model

Linear perturbations in a uniform Newtonian gas model obey ω²=c_s²k²−4πGρ₀.

ModelEarth & cosmosThermal free–free radio emission

Electron–ion acceleration produces continuum emission without capture.

ModelEarth & cosmosSynchrotron emission and electron energy loss

A magnetically deflected electron radiates P=2σ_TcU_Bβ²γ²sin²α.

ModelEarth & cosmosThomson inverse-Compton electron loss

An electron in an isotropic soft-photon field loses net power P_IC=(4/3)σ_TcU_radβ²γ² in the Thomson limit.

ModelEarth & cosmosRepresentative stellar fusion isotope pathways

The ppI branch builds deuterium and helium-3 before combining two helium-3 nuclei.

ModelEarth & cosmosConserved fluxes across a normal gas shock

A steady planar normal shock conserves mass, momentum and total-enthalpy flux across its thin transition: [ρu]=[ρu²+P]=[ρu(h+u²/2)]=0.

ModelEarth & cosmosSolar wind and magnetospheric energy transfer

The solar wind carries charged particles, including protons and electrons, and solar magnetic field into interplanetary space.

ModelEarth & cosmosCosmic-ray composition and secondary-particle evidence

In charged-particle usage, cosmic rays include energetic nuclei and electrons from space.

Empirical findingEarth & cosmosClassical event horizon and Schwarzschild radius

A classical black-hole event horizon is a causal boundary: signals from its interior cannot reach distant future observers in the exterior.

DefinitionEarth & cosmosPoint-mass deflection and Einstein angular radius

A point mass in the weak-field geometric-optics limit deflects light by magnitude α̂=4GM/(c²b).

MethodEarth & cosmosPhoton–baryon acoustic structure in the CMB

Before recombination, scattering tightly coupled photons and baryons.

ModelBiologyCohort survival and net reproduction

A cohort life table follows individuals born together.

ModelBiologyEuler–Lotka growth and age structure

In a fixed density-independent age model, the growth factor λ satisfies Σ_{x≥1}λ^(−x)l_xm_x=1.

ModelBiologyLevins patch occupancy and persistence

A simple internally colonized metapopulation tracks the occupied fraction p of equivalent habitat patches.

ModelBiologyOccupancy and imperfect species detection

Failure to detect a species does not establish absence.

MethodBiologyIndividual-based rarefaction and richness sampling

For a collection containing N individuals with N_i in each observed species, the expected species count in a uniformly drawn subset of n individuals without replacement is E[S_n]=Σ_i[1−C(N−N_i,n)/C(N,n)].

MethodBiologyPerturbation, rescue and gene-function evidence

A genetic perturbation tests a causal prediction when the intended change and relevant phenotype are measured against appropriate controls.

MethodChemistryGreen chemistry design principles and lifecycle scope

Green chemistry evaluates product and process design to reduce hazardous inputs, releases and waste over a stated lifecycle.

Method
ModelSource checked

Core collapse and thermonuclear stellar explosions

Earth & cosmos

Core-collapse supernovae involve loss of support in an evolved stellar core, rapid contraction and an explosion whose energy transfer involves dense matter and neutrinos.

Key knowledge

Core-collapse supernovae involve loss of support in an evolved stellar core, rapid contraction and an explosion whose energy transfer involves dense matter and neutrinos. Electron capture can reduce electron support; photodisintegration can absorb energy. Type Ia supernovae instead arise from thermonuclear burning in a white-dwarf system. Spectral classification and physical mechanism are distinct: core-collapse events need not retain a hydrogen envelope, and no single binary progenitor channel accounts by definition for every Type Ia event.

Conditions and scope

  • Outcomes depend on core structure, composition, envelope loss, binary evolution and explosion dynamics. Not every collapsing star produces the same successful explosion or compact remnant.
  • Treat thermonuclear ignition and flame development as model-dependent; no universal Chandrasekhar-mass trigger, identical luminosity, fixed mass cutoff or complete neutrino-transport calculation is asserted.
Sources · 2

References

Sources retain their recorded scope. A source link alone does not establish verification of every statement.

  1. Stellar Structure and Evolution, §§13.1–13.3: spectral/physical classes, core support loss and white-dwarf thermonuclear burningOnno R. Pols — Utrecht UniversityReference guide · PDFucolick.orgRead source
  2. Astronomy2e23.3: supernova observations and neutrino evidenceAndrew Fraknoi, David Morrison and Sidney C. Wolff — OpenStaxReference guideopenstax.orgRead source

Evidence and review

Read Pols printed pp.189–191 and196–198 for classification, support loss, collapse energetics and thermonuclear mechanism, plus OpenStax actual neutrino-observation body. Retained qualitative distinct mechanisms and progenitor uncertainty; excluded source universal all-non-Ia-core-collapse and all-Ia-Chandrasekhar statements, old event counts and fixed observational rates.

2026-10-10 · Independent AI editorial review: All44 exact root-authored compact records, equations/variable units/conditions and140 origin edges accepted after independently reading final6/18 with bounded primary bodies and matching prior38/122 scientific fingerprints unchanged. Exact claim/edge review is distinct from combined inventory scope and separate CLE26 approval; no entire cited books or old-corpus experimental revalidation is asserted. Receipt: cosmos-completion-independent-content-and-inventory-review.1.

Related reference entries

Explore relationships within this area of study and its connections to other areas.

Showing 1–6 of 6 relationships

Scientific relationships · 6 / 6

The relationship type describes the connection. Its linked statements, sources and conditions define the scope.

  1. Related to
    Relationship sources · 2

    Linked statements

    • Core-collapse supernovae involve loss of support in an evolved stellar core, rapid contraction and an explosion whose energy transfer involves dense matter and neutrinos. Electron capture can reduce electron support; photodisintegration can absorb energy. Type Ia supernovae instead arise from thermonuclear burning in a white-dwarf system. Spectral classification and physical mechanism are distinct: core-collapse events need not retain a hydrogen envelope, and no single binary progenitor channel accounts by definition for every Type Ia event.

    Electron support and thermonuclear ignition must be distinguished.

  2. Related to
    Relationship sources · 2

    Linked statements

    • Core-collapse supernovae involve loss of support in an evolved stellar core, rapid contraction and an explosion whose energy transfer involves dense matter and neutrinos. Electron capture can reduce electron support; photodisintegration can absorb energy. Type Ia supernovae instead arise from thermonuclear burning in a white-dwarf system. Spectral classification and physical mechanism are distinct: core-collapse events need not retain a hydrogen envelope, and no single binary progenitor channel accounts by definition for every Type Ia event.

    Nuclear transformations affect energy and element production.

  3. Related to
    Relationship sources · 2

    Linked statements

    • Core-collapse supernovae involve loss of support in an evolved stellar core, rapid contraction and an explosion whose energy transfer involves dense matter and neutrinos. Electron capture can reduce electron support; photodisintegration can absorb energy. Type Ia supernovae instead arise from thermonuclear burning in a white-dwarf system. Spectral classification and physical mechanism are distinct: core-collapse events need not retain a hydrogen envelope, and no single binary progenitor channel accounts by definition for every Type Ia event.

    Collapse and explosion affect the resulting compact object.

  4. Related to
    Relationship sources · 3

    Linked statements

    • In a circular two-point-mass binary's corotating frame, the effective potential per mass is Φ_eff=−GM₁/r₁−GM₂/r₂−Ω²(x²+y²)/2, with origin at the barycentre and Ω²=G(M₁+M₂)/a³. Its equipotentials approximate the shape of a synchronized hydrostatic donor. Filling the donor's critical Roche lobe permits flow toward the companion through the inner neck; companion winds provide another supply route. Transfer changes mass and angular momentum, so isolated-star evolution can fail.

    Binary supply changes possible thermonuclear progenitor conditions.

  5. Related to
    Relationship sources · 2

    Linked statements

    • In charged-particle usage, cosmic rays include energetic nuclei and electrons from space. Magnetic deflection can obscure their arrival-direction connection to sources. Interactions of nuclei with interstellar matter produce fragments called secondaries; measured primary/secondary abundances constrain propagation jointly with reaction cross sections and transport models.

    Remnant environments are candidate acceleration settings, not unique source identifications.

  6. Related to
    Relationship sources · 1

    Linked statements

    • Core-collapse models couple dense-matter EOS, fluid motion and flavor/energy-dependent neutrino radiation. Boltzmann and moment closures approximate different angular information; a ray-by-ray approximation does not solve arbitrary lateral transport.

    Conceptual association supported by the recorded research scope; this relation does not assert a proven derivation or mandatory prerequisite.

Entry detailsPermanent link to this entry ↗
Record identity
uni-cosmos-supernova-mechanisms
Revision
core.1
Structured reference record
University core expansion