Japanese astronomers observed the nucleus of a dying comet
(NASA / JPL-Caltech / GSSR)
Japanese astronomers observed the comet P/2016 BA14 (PANSTARRS) with the Subaru telescope during its approach to Earth.
They concluded that one of the possible endings of the life of periodic comets may be an inactive small body covered with large grains of phyllosilicates and organic matter. The article was published in Icarus.
Comets are small bodies of the solar system, rich in frozen volatiles, they can tell a lot about the composition of the matter from which our planetary system was formed.
Observations of periodic comets that repeatedly come close to the Sun demonstrate the constant physical and chemical evolution of their nuclei.
To distinguish the initial properties of cometary nuclei from those that appear after encounters with our star, scientists need to clearly understand the effect of solar heating on cometary nuclei, and this requires large amounts of observational data.
Now a group of astronomers led by Takafumi Ootsubo from the National Astronomical Observatory of Japan published the results of observations of the periodic comet P/2016 BA14 (PANSTARRS), which belongs to the Jupiter family and flew 3.6 million kilometers from Earth.
30 hours earlier, astronomers carried out observations of it in the infrared wavelengths using the COMICS (Cooled Mid-infrared Camera and Spectrometer) instrument mounted on the 8.2-meter Subaru ground-based telescope.
Observations carried out with the help of other telescopes, showed that the rate of formation of gas and dust by the nucleus was extremely low even near the point of perihelion, located at a distance of 1.012 astronomical units from the Sun.
This indicated that comet P/2016 BA14 could almost completely deplete its reserves of volatiles. In addition, its orbit of was noted to be similar to that of 252P/LINEAR, indicating that both comets could be fragments of a larger body.
Both of these theories need to be tested with new observational data.
An analysis of observational data from the Subaru telescope showed that the effective diameter of the P/2016 BA14 core is 0.8 ± 0.2 kilometers, and its surface temperature is 343 Kelvin.
Observations did not reveal dehydrated particles of minerals, such as olivine and pyroxene, on the surface of the core, but indicated the presence of large grains of phyllosilicates, such as chlorite, clinochlore and serpentine, and organic matter.
This means that the surface of the comet's nucleus could have been heated to at least 600 kelvin during past encounters with the Sun or the nucleus initially contained many grains of dehydroxylated phyllosilicates.
If such minerals are found in the future in the coma of comet 252P/LINEAR, this will indicate the relationship of the two comets.
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