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In astronomy or planetary science, the frost line, also known as the snow line or ice line, is the minimum distance from the central protostar of a solar nebula where the temperature is low enough for volatile compounds such as water, ammonia, methane, carbon dioxide and carbon monoxide to condense into solid grains, which will allow their accretion into planetesimals.
Also actiniform. Describing a collection of low-lying, radially structured clouds with distinct shapes (resembling leaves or wheels in satellite imagery), and typically organized in extensive mesoscale fields over marine environments. They are closely related to and sometimes considered a variant of stratocumulus clouds. actinometer A scientific instrument used to measure the heating power of ...
This glossary of astronomy is a list of definitions of terms and concepts relevant to astronomy and cosmology, their sub-disciplines, and related fields. Astronomy is concerned with the study of celestial objects and phenomena that originate outside the atmosphere of Earth. The field of astronomy features an extensive vocabulary and a ...
In geology, the frost line is the level down to which the soil will normally freeze each winter. By an analogy, the term is introduced in other areas. Frost line (astrophysics), a particular distance in the solar nebula from the central protosun where it is cool enough for hydrogen compounds such as water, ammonia, and methane to condense into solid ice grains.
The boundary of the region where ice could form in the early Solar System is known as the frost line (or snow line), and is located in the modern asteroid belt, between about 2.7 and 3.1 astronomical units (AU) from the Sun. [23] [24] It is therefore necessary that objects forming beyond the frost line–such as comets, trans-Neptunian objects ...
An additional difference is the composition of the planetesimals, which in the case of giant planets form beyond the so-called frost line and consist mainly of ice—the ice to rock ratio is about 4 to 1. [29] This enhances the mass of planetesimals fourfold.
Planetesimals beyond the frost line accumulated up to 4 M E within about 3 million years. [38] Today, the four giant planets comprise just under 99% of all the mass orbiting the Sun. [b] Theorists believe it is no accident that Jupiter lies just beyond the frost line. Because the frost line accumulated large amounts of water via evaporation ...
An artist's illustration giving a simple overview of the main regions of a protoplanetary disk, delineated by the soot and frost line, which for example has been observed around the star V883 Orionis. [15] The nebular hypothesis of solar system formation describes how protoplanetary disks are thought to evolve into planetary systems.