In a significant astronomical event, Indian scientists have observed the mysterious interstellar comet 3I/ATLAS. This observation was made by scientists from the Physical Research Laboratory (PRL), part of ISRO, using their 1.2-metre telescope at Mount Abu. The comet, which is the third known interstellar comet to enter our solar system, was discovered by the ATLAS survey in July 2025.
Currently, it is moving away from the inner solar system on a hyperbolic path and will never return, making these observations crucial.
The observations were conducted between November 12 and 15, 2025, utilising both imaging and spectroscopic modes. This enabled detailed data collection on the comet's structure and composition. The telescope images, displayed in false colour, revealed a bright circular halo of gas and dust around the comet's nucleus, known as the coma.
The coma forms through sublimation, where the sun's heat turns the ice on the comet's nucleus into vapour, releasing gas and dust into space. These observations have provided insights into the activity of this interstellar body.
Comet 3I/ATLAS is of particular interest to scientists because it originates from another star system. Its 3,500-year-old ice and unusual chemistry offer rare evidence about the matter formed outside our sun.
The telescope also captured the comet's dust tail, extending away from the sun, and its ion tail, made of ionised gas pushed by the solar wind. Deep wide-field and multiband images showed these features in detail. The PRL team also collected spectral data showing molecular bands like CN, C2, and C3, which are also found in comets from our solar system.
These emission features help identify the comet's chemical makeup. Researchers calculated the gas release rate, or 'production rate', measuring the comet's activity.
The Mount Abu observatory, located near Gurushikhar at an altitude of 1,680 metres, is designed for astronomical research, including exoplanet hunting and solar system studies. This observation has added valuable knowledge about interstellar objects and their characteristics.