Scientists from the Physical Research Laboratory (PRL) have used their 1.2-metre telescope at Mount Abu to study the rare interstellar comet 3I/ATLAS. The comet is currently moving away from the inner Solar System after passing closest to the Sun recently.

The observations were carried out between November 12 and 15, 2025, using both imaging and spectroscopic techniques.This allowed the scientists to collect detailed information about how the comet looks and what it is made of.

The images captured by the telescope, shown in false colours, reveal a round, bright cloud around the comet called the coma. A coma forms when sunlight heats the comet and causes the ice on its surface to turn into gas. This gas escapes into space, carrying dust with it and creating a glowing envelope around the nucleus.

If the comet has a dust tail, it stretches away from the Sun, as seen from Earth. The PRL team took deep, wide-field images in different filters, which also showed signs of the comet’s ion tail, a tail made of charged particles that gets pushed by the solar wind.

Apart from taking images, the scientists also recorded the comet’s spectrum, the light it emits at different wavelengths, just before morning twilight. The spectral data showed strong emission lines of CN (cyanogen), C₂, and C₃ molecules. These features are common in comets from our Solar System and help scientists identify the chemicals present in the comet.

The team also calculated the comet’s gas production rate, which tells how much gas is being released from the comet as it heats up. This helps measure its activity and compare it with other comets. The Mount Abu observatory, located near Gurushikhar at an altitude of 1,680 meters, is an important site for astronomical research. The 1.2-m telescope is used for studying exoplanets, comets, planets, and other cosmic events, and has contributed valuable observations over many years.

These new observations by PRL scientists, who work under ISRO, provide important information about this unusual interstellar comet. Since 3I/ATLAS comes from outside our Solar System, studying it helps scientists learn more about material from other star systems and understand how such visitors behave. Meanwhile, NASA is expected to hold a press briefing tonight, where it will release the images captured from Mars orbit when the comet was closest to the Sun.