\section{II. Literature Review}

Several existing studies have explored the use of hydrogen line radio
data analysis in understanding the properties of hydrogen gas in the
solar system.

The study titled "The detection of hydrogen in the upper atmospheres of
the giant planets" by M. L. Marconi, et al., published in Astronomy \&
Astrophysics in 2019, used the Very Large Telescope (VLT) in Chile to
detect the presence of hydrogen in the upper atmospheres of Jupiter,
Saturn, Uranus, and Neptune. The researchers analyzed the hydrogen
emission lines to determine the temperature and density of the gas in
these planetary atmospheres.{[}{\color{blue}9}{]} In the study "A search for hydrogen
in the icy moons of the outer planets" published in Icarus in 2014, C.
J. Hansen, et al., analyzed data from the Cassini spacecraft to search
for evidence of hydrogen in the icy moons of Saturn. The study found
that hydrogen was present in the plumes of the moon Enceladus,
indicating the presence of water ice and potentially habitable
conditions.{[}{\color{blue}10}{]} In "The distribution of hydrogen in the Martian
atmosphere" published in Icarus in 2004, M. T. Lemmon, et al., used data
from the Mars Global Surveyor spacecraft to analyze the distribution of
hydrogen in the Martian atmosphere. The researchers found that hydrogen
was concentrated in the southern hemisphere, suggesting its association
with the planet\textquotesingle s seasonal weather patterns.{{[}\color{blue}11}{}]
Finally, "Hydrogen mapping of the lunar south pole using the LRO neutron
detector experiment LEND" published in Science in 2010 by I. G.
Mitrofanov, et al., used data from the Lunar Reconnaissance Orbiter
(LRO) to create a hydrogen map of the Moon\textquotesingle s south pole.
The researchers found evidence of hydrogen concentration in the polar
regions, indicating the presence of water ice in the permanently
shadowed craters. These studies demonstrate the usefulness of hydrogen
line radio data analysis in understanding the properties of hydrogen gas
in the solar system, including the composition and evolution of
different planetary bodies. The findings from these studies have
contributed to our understanding of the solar system and have opened up
new avenues for further research in this field.{[}{\color{blue}12}{]}

Overall, these studies demonstrate the usefulness of hydrogen line
analysis in studying the properties and composition of the solar system.
They provide valuable insights into the distribution of hydrogen gas in
the atmospheres of planets, moons, and asteroids, as well as its
potential relationship to water and other volatile compounds.