Estimates of mass and angular momentum in the oort cloud

Area of Science:

• Astronomy and Astrophysics
• Planetary Science

Background:

• The Oort cloud is a theoretical spherical cloud of comets surrounding the solar system.
• Estimating the mass and angular momentum of the Oort cloud is crucial for understanding solar system formation and evolution.
• Previous models often treated the Oort cloud as a uniform distribution of icy bodies.

Purpose of the Study:

• To estimate the unseen mass of cometary nuclei within the heliocentric distance range of 3 x 10^3 to 2 x 10^4 AU.
• To determine the mass and angular momentum of the Oort cloud.
• To compare the Oort cloud's mass and angular momentum with the early solar system and the current planetary system.

Main Methods:

• Modeling unseen mass distribution based on cometary nuclei.
• Assuming the Oort cloud as a rarefied halo surrounding a dense inner cometary cloud.
• Using Comet Halley's mass and albedo as a typical representation for cometary populations.

Main Results:

• Estimated mass of cometary nuclei between 3 x 10^3 and 2 x 10^4 AU is approximately 0.03 solar masses.
• Angular momentum in this region is estimated to be of the order of 10^52 to 10^53 g-cm^2/s.
• The Oort cloud may contain approximately 100 Earth masses (M⊕) with angular momentum potentially exceeding the current planetary system's by one order of magnitude.

Conclusions:

• The Oort cloud's mass is comparable to the total mass of the early solar system before volatile loss.
• The Oort cloud's angular momentum is significant, potentially rivaling that of the early planetary system.
• These findings provide new insights into the distribution of mass and angular momentum in the outer solar system.