Comet 238P / Read

1. ----------------------------

Title - https://en.wikipedia.org/wiki/238P/Read

Extracts - 238P/Read (P/2005 U1) is a main-belt comet, discovered in 2005 by astronomer Michael Read. It has an orbit within the asteroid belt and has displayed the coma of a traditional comet. It fits the definition of an Encke-type comet.

Observations of 238P when it was inactive in 2007 suggests that it has a small nucleus only about 0.6 km in diameter. Its next perihelion will be in Jan 2028.

The comet was observed by JWST during the 2022 perihelion and it was found spectrographicaly that its coma was composed of water vapor & lacked significant CO2.

2. ----------------------------

Title - Comet 238P / Read & main-belt asteroids

By - Cosmos blog, ISAS-JAXA

Extracts - The article starts off with the traditional view that asteroids & comets have distinct composition & place of origin, that asteroids are rocky bodies from the inner solar system & comets are icy bodies from from the outer solar system [ This is a ancient, outdated, wrong & unscientific view, in defiance of evidence & fails to meet the standards of scientific method. ]

"The samples from such a small body with the intermediate characteristics of the comet and asteroid (Jupiter family comets with low cometary activity) are essential in understanding the physical and chemical differences between asteroids and comets and the origin of the Solar System."

- Shimaki Yuri, senior scientist at ISAS-JAXA

[ This suggests that the physical and chemical differences between asteroids and comets are not clearly understood. ]

"It is certain that the material that made up the present-day Ryugu previously existed in icy bodies soon after the formation of the Solar System. If these icy bodies are recognized as comets, then we can say that Ryugu must once have been a comet. The question is then when the ice was lost from the icy body. These observations show that at least some asteroids located in the asteroid belt still contain ice."

This transport between the outer and inner Solar System may not only have influenced the composition of the planets, but also delivered the ingredients needed to make the young Earth habitable, says Associate Professor Furukawa Yoshihiro from Tohoku University.

Looking at the near-infrared reflectance spectrum from the surface of this object (Comet 238P/Read), it resembles the spectrum from certain types of asteroid that are abundant in this region. It is thought that these similar asteroids could therefore have a similar composition & behaviour to this main-belt comet (suggesting that main-belt asteroids with similar spectra also do not contain carbon monoxide or carbon dioxide and that similar cometary activity can be triggered in them).

[ Meaning : there is no difference between comet 238P & other main belt asteroids, based on the reflectance spectrum. This suggests a similar composition. ]

The main-belt comets are small bodies in asteroid-like orbits that show cometary activities. 

Small bodies in comet-like orbits that do not show cometary activities are called extinct comets.

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