AI 中文总结
研究最小伸缩子引力（MDG）中的静态球对称白矮星，发现其最大质量低于广义相对论结果，引入自由边界配点法求解，给出λ_Φ的约束，为相关引力理论提供观测限制。
AI 中文摘要
我们研究最小伸缩子引力（MDG）中的静态、球对称白矮星，MDG是一个耦合常数α²=1/3固定、自由康普顿长度为λ_Φ的Brans-Dicke理论。求解完整的相对论结构方程后发现，对于任意λ_Φ，MDG白矮星严格属于钱德拉塞卡质量以下的天体：最大质量从广义相对论（GR）中的1.425倍太阳质量，降至λ_Φ=200km时的1.27倍太阳质量，再降至λ_Φ=500km时的1.09倍太阳质量。MDG对最大质量的降低比例对于物态方程具有鲁棒性。计入接近质量 shedding的刚体旋转后，与观测到的最大质量白矮星的一致性要求λ_Φ≲300km；独立的引力红移约束给出λ_Φ≲720km。由于伸缩子质量与密度无关，同一耦合会导致开普勒推断的GM_⊕出现百分级的高度依赖，可从太阳系侧对其进行约束。为解决该问题，我们引入了带有线性化外部Robin条件的自由边界配点法，该方法消除了打靶法的指数刚度，可在双精度下处理屏蔽区域。
英文摘要
We study static, spherically symmetric white dwarfs in minimal dilatonic gravity (MDG) -- a Brans-Dicke theory with fixed coupling $α^2=1/3 $ and free Compton length $λ_Φ$. Solving the full relativistic structure equations we find that MDG white dwarfs are strictly sub-Chandrasekhar for every $λ_Φ$: the maximum mass falls from $1.425\,M_\odot$ in GR to $1.27\,M_\odot$ at $200$ km and $1.09\,M_\odot$ at $500$ km. The ratio by which MDG reduces the maximum mass is robust against the equation of state. Including rigid rotation near mass shedding, consistency with the most massive observed white dwarfs restricts $λ_Φ \lesssim 300$ km. An independent gravitational-redshift bound gives $λ_Φ \lesssim 720$ km. Because the dilaton mass is density-independent the same coupling produces a percent-level altitude dependence of the Kepler-inferred $ GM_\oplus$, constraining it from the Solar-System side. To tackle the problem, we introduce a free-boundary collocation method with a linearized-exterior Robin condition that eliminates the exponential stiffness of shooting methods and gives access to the screened regime in double precision.
Comments14 pages, 6 figures, 5 tables
