BENGALURU: The Indian Space Research Organisation’s (ISRO’s) Physical Research Laboratory (PRL) scientists on Wednesday took a close look at the mysterious interstellar comet 3I-Atlas that is currently cruising through the inner planets of the Solar System towards the Sun.

They have shared details of the recent findings about 3I/Atlas, including its tail.

The observations were made with the PRL’s 1.2m telescope. The comet is currently on its way out of the inner solar system after the perihelion passage – the point in its elliptical orbit closest to the sun.

The images captured showed a near-circular coma, the researchers noted. “The coma is the large, glowing atmosphere of gas and dust that forms around its nucleus as it gets closer to the Sun.

It is created when the Sun’s heat causes the frozen ices on the nucleus to vaporize, or sublimate (rate of release), releasing gas and dust that form a large, diffuse cloud. In the present observing geometry, the dust tail, if present, would be pointing away from the Sun behind the comet as seen from the Earth, while deep wide field multi-band images may show the ion tail.”

Apart from imaging, scientists also acquired a spectrum of the light from the comet, before the start of morning twilight. The result shows prominent emission features commonly seen in Solar system comets – the CN, C2 and C3 bands in the shorter wavelength side of the spectrum, they said.

Researchers said the rate of release of gas from the nucleus into the coma is referred to as the production rate. This is a measure of the comet’s activity level. The production rate varies throughout the comet’s orbit and is driven by factors like distance from the sun and the comet’s internal composition.

“But in case of 3I/ATLAS, the production rates for the prominent bands (emissions pertaining to the constituent molecules) were computed with limiting values around 1025 molecules/second,” they said.