White-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).
Key knowledge
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). As electron momenta become relativistic, the pressure approaches K_URρ^(4/3), an n=3 polytrope whose mass is independent of central density. Its ideal limiting mass is M_Ch=4π ω₃[K_UR/(πG)]^(3/2), proportional to μₑ^(−2). This is a limiting electron-support model, not a universal initial stellar-mass threshold.
Values and equations
K_UR=ℏc(3π²)^(1/3)/[4(μₑm_u)^(4/3)]; M_Ch=4π ω₃[K_UR/(πG)]^(3/2)
- K_UR
- constant in P=K_URρ^(4/3) Pa (kg m⁻³)^(−4/3)
- μₑ,ω₃
- mean mass per electron in m_u units and Lane–Emden mass factor 1
- m_u,M_Ch
- atomic mass constant and ideal limiting mass kg
- ℏ
- reduced Planck constant J s
- c
- vacuum light speed m s⁻¹
- G
- gravitational constant m³ kg⁻¹ s⁻²
Conditions and scope
- Define μₑ=ρ/(nₑm_u), with m_u the atomic mass constant, fixed composition, zero surface pressure and negligible rotation, thermal, magnetic and nonideal terms. ω₃=−ξ₁²θ′(ξ₁) for the regular n=3 Lane–Emden solution's first zero.
- General relativity, Coulomb interactions, electron capture, composition and finite-temperature structure alter real stability. Reaching an approximate mass alone specifies neither a unique explosion mechanism nor neutron-star support.
Sources · 2
References
Sources retain their recorded scope. A source link alone does not establish verification of every statement.
Evidence and review
Read Pols printed pp.49–50 and170–171, actual mass–radius/limiting-mass equations and noninteracting/Coulomb/electron-capture limits; read MIT problem3's explicit μₑ and n=3/2 versus3 setup. Derived composition powers by substituting nₑ=ρ/(μₑm_u) into the reviewed electron-pressure and Lane–Emden scales. No dated observational upper bound or universal source initial-mass assertion adopted.
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.
Entry details
Permanent link to this entry ↗- Record identity
- uni-cosmos-white-dwarf-support-limit
- Revision
- core.1
- Structured reference record
- University core expansion