有效半径
有效半径（
）是一个星系辐射出系统总光度一半的半径。假设一个星系，有内在的球队称或者至少在天球平面上看见的圆对称。另外，半光度的轮廓或等光强线可以适用在球或圆不对称的天体。
是非常重要的尺度，在佛科留斯![\sqrt[4] R](/uploads/202501/10/6d014f0942cddb3ffb67a23df5be2cfb5343.png)
定律，它描述物体表面具体光度下降与半径的函数：
![I(R) = I_e \cdot e^{-7.67 \left( \sqrt[4]{\frac R {R_e}} - 1 \right)}](/uploads/202501/10/2cbdc8b3aecb5e158f2b371f2fbb0bb85343.png)
此处
是表面在
. At 
的亮度，
因此，中央的表面光度大约是
。
Effective radius
中文百科
英语百科
Effective radius 有效半径
The effective radius (
) of a galaxy is the radius at which half of the total light of the system is emitted. This assumes the galaxy has either intrinsic spherical symmetry or is at least circularly symmetric as viewed in the plane of the sky. Alternatively, a half-light contour, or isophote, may be used for spherically and circularly asymmetric objects.
- Effective competition的意思
- effective component的意思
- effective component of current的意思
- effective compression ratio的意思
- effective computable的意思
- effective concentration的意思
- effective concentration of network chains的意思
- effective conductance的意思
- effective conductant的意思
- effective conductivity的意思
- effective confining pressure的意思
- effective confusion area的意思
- effective conjugate的意思
- effective constant的意思
- effective constituent的意思
- effective constraint length的意思
- effective consuming power的意思
- effective consumption的意思
- effective contact的意思
- effective contact area的意思
- effective contour的意思
- effective control的意思
- effective control over all planned investment in fixed assets的意思
- effective convergence的意思
- Effective convexity的意思