- 4230 - CENTAURS - discovered in asteroid belt. Centaurs are small planetary bodies that orbit between Jupiter and Neptune and have baffled astronomers for sharing characteristics with both asteroids and comets. Centaurs got their name after the mythical half-horse, half-human creatures called centaurs due to their dual characteristics
--------------------- 4230 - CENTAURS - discovered in asteroid belt
- James Webb Space
Telescope (JWST) has conducted a first-time detection of carbon dioxide in a
Centaur, this one designated “39P/Oterma”. A Centaur is a small planetary body
that orbits between Jupiter and Neptune and frequently crosses the orbits of
one or more of the gas giant planets within our solar system. While no Centaur
has been imaged up-close, they typically exhibit a combination of attributes
between comets and asteroids.
-
- While carbon
monoxide has been detected in two known centaurs, this 2023 discovery could
mark a turning point in how scientists understand the formation, evolution, and
composition of not only Centaurs, but of the early solar system.
-
- Centaurs are
important to study since they are fairly well-preserved objects in space that
can provide insight on the chemical composition and physical processes of the
early solar system.
-
- Centaur 39P/Oterma
was discovered on April 8, 1943, by Finnish astronomer, who was the first woman
to earn PhD in astronomy in Finland.
While 39P/Oterma has long been classified as an inactive comet, it
currently exhibits a Centaur-like orbit between Jupiter and Saturn, meaning it
doesn’t approach the Sun, and has a radius of approximately 1.55 miles.
-
- 39P/Oterma is what
we call an active centaur, a centaur that develops a coma and a tail like a
normal comet. Since they are active, we
can use spectroscopy to observe molecules in their coma to gain insights into
their composition.
-
- Investigations of
the characteristics of 39P/Oterma were made while it was orbiting close to its
perihelion (closest distance to the Sun) at 5.82 astronomical units (AU) from
the Sun in July 2022. For context, the perihelion of 39P/Oterma has gradually
increased since its discovery: 3.39 AU (1958), 5.47 AU (1983), and 5.71 AU
(2023), and is projected to reach 5.91 AU and 6.15 AU in 2042 and 2246.
-
- After analyzing the
JWST NIRSpec data, the researchers confirmed the first detection of carbon
dioxide in any Centaur, and the lowest amount of carbon dioxide ever detected
in any Centaur or comet. They also did not detect traces of water or carbon
monoxide, which are traditionally detected in Centaurs.
-
- The capabilities
of JWST are able to see low production rates of a relatively small object that
is very far away. And, though the
production rates are low, it shows a different chemical behavior from another
Centaur, 29P/SW1, seen at a similar distance (6 AU). This difference in
chemical behavior could be from the very different sizes of Centaurs 29P and
39P, or from having different orbital histories, or starting out with different
compositions.
-
- 39P/Oterma is an active centaur, a centaur that develops a
coma and a tail like a normal comet.
Since they are active, we can use spectroscopy to observe molecules in
their coma to gain insights into their composition.
-
- The finding of
carbon dioxide in a Centaur could be a gamechanger in terms of understanding
the compositions and characteristics of Centaurs, asteroids, and comets
throughout the solar system, along with potentially gaining better insight into
the formation and evolution of the solar system, overall.
-
-
November 21, 2023
CENTAURS -
discovered in asteroid belt
4230
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Tuesday, November 21, 2023 ---------------------------------
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