Marochnik L S, Mukhin L M, Sagdeev R Z
Science. 1988 Oct 28;242(4878):547-50. doi: 10.1126/science.242.4878.547.
Estimates can be made of unseen mass (in the form of cometary nuclei) at the heliocentric distances between 3 x 10(3) and 2 x 10(4) astronomical units(AU) under the assumptions (i) that the Oort cloud is a rarefied halo surrounding the core (dense, inner cometary cloud) and (ii) that the mass and albedo of comet Halley is typical for comets both in the core and the Oort cloud populations. The mass appears to be approximately 0.03 solar masses, with angular momentum of the order of 10(52) to 10(53) g-cm(2)/s. This mass is of the order of the total mass of the planetary system before the loss of volatiles. This leads to an estimate of a mass M(o) approximately 100 M( plus sign in circle) (where M( plus sign in circle) is the mass of Earth) concentrated in the Oort cloud (r > 2 x 10(4) AU) with an angular momentum that may exceed the present angular momentum of the whole planetary system by one order of magnitude. The present angular momentum of the Oort cloud appears to be of the same order as the total angular momentum of the planetary system before the loss of volatiles.
在以下假设条件下，可以估算出在日心距离为3×10³至2×10⁴天文单位（AU）之间以彗核形式存在的不可见质量：（i）奥尔特云是围绕核心（致密的内彗星云）的稀薄晕；（ii）哈雷彗星的质量和反照率对于核心和奥尔特云群体中的彗星来说具有典型性。该质量似乎约为0.03个太阳质量，角动量约为10⁵²至10⁵³克·厘米²/秒。这个质量与行星系统在挥发物损失之前的总质量相当。这导致估计有一个质量Mₒ约为100M⊕（其中M⊕是地球的质量）集中在奥尔特云（r>2×10⁴AU）中，其角动量可能比整个行星系统目前的角动量超出一个数量级。奥尔特云目前的角动量似乎与行星系统在挥发物损失之前的总角动量处于同一量级。
