Center of Applied Space Technology and Microgravity (ZARM), University of Bremen, Am Fallturm, 28359 Bremen, Germany, EU.
Phys Rev Lett. 2015 Apr 17;114(15):151102. doi: 10.1103/PhysRevLett.114.151102. Epub 2015 Apr 15.
According to the no-hair theorem, static black holes are described by a Schwarzschild spacetime provided there are no other sources of the gravitational field. This requirement, however, is in astrophysical realistic scenarios often violated, e.g., if the black hole is part of a binary system or if it is surrounded by an accretion disk. In these cases, the black hole is distorted due to tidal forces. Nonetheless, the subsequent formulation of the no-hair theorem holds: The contribution of the distorted black hole to the multipole moments that describe the gravitational field close to infinity and, thus, all sources is that of a Schwarzschild black hole. It still has no hair. This implies that there is no multipole moment induced in the black hole and that its second Love numbers, which measure some aspects of the distortion, vanish as was already shown in approximations to general relativity. But here we prove this property for astrophysical relevant black holes in full general relativity.
根据无毛定理，如果没有其他引力场源，静态黑洞由施瓦西时空中描述。然而，在天体物理现实场景中，这一要求经常被违反，例如，如果黑洞是双星系统的一部分，或者如果它被吸积盘包围。在这些情况下，黑洞由于潮汐力而变形。尽管如此，随后的无毛定理的表述仍然成立：变形黑洞对描述无限远处引力场的多极矩的贡献，因此对所有源的贡献，都是施瓦西黑洞的贡献。它仍然没有毛发。这意味着黑洞不会产生多极矩，而它的第二个爱数值，用于衡量变形的某些方面，已经在广义相对论的近似中消失了。但是在这里，我们在全广义相对论中为天体物理相关的黑洞证明了这一性质。
