| Name: Himadri Sekhar Das |
| Affiliation: Assam University, Silchar |
| Conference ID: ASI2026_513 |
| Title: Photometry, Spectroscopy, and Polarimetry of the Interstellar Comet 3I/ATLAS |
| Abstract Type: Invited |
| Abstract Category: Sun, Solar System, Exoplanets, and Astrobiology |
| Author(s) and Co-Author(s) with Affiliation: Himadri Sekhar Das(Assam University, Silchar-788011, India), Biki Prasad(Assam University, Silchar-788011, India), Bhaskarjyoti Barman(Assam University, Silchar-788011, India), Monoswini Chakravorty(Assam University, Silchar-788011, India), Nambram Niroda Devi(Assam University, Silchar-788011, India), Bhaskar Goswami(Assam University, Silchar-788011, India), Sanchali Nath Mazumdar(Assam University, Silchar-788011, India), Biman Jyoti Medhi(Gauhati University, Guwahati-781014, India), Jeewan Chandra Pandey(ARIES, Nainital-263002, India) |
| Abstract: Comet 3I/ATLAS is only the third interstellar object discovered within our solar system. Previously, 1I/Oumuamua and 2I/Borisov were the first two such objects seen in our solar system. When we find one of these “visitor” comets, it provides us with an opportunity to study material formed in an extrasolar planetary system. This gives us an opportunity to directly observe how comets form in other areas of the universe, beyond our solar system, and also provides insight into the material that exists around distant stars.
We present multi-wavelength observations of comet 3I/ATLAS obtained during December 2025 from ARIES, Nainital. Linear polarimetric observations in the R filter were conducted on December 8-10 using the AIMPOL instrument mounted on the 1-m Sampurnanand Telescope in Nainital. These measurements provide insight into the physical properties and composition of dust particles in the coma. Subsequently, complementary optical photometric observations in the Rp filter and NIR photometry in JHK filters were obtained on December 15 using the 3.6-m Devasthal Optical Telescope. Near-infrared spectroscopic observations spanning the 0.55–2.54 μm wavelength range enable the investigation of molecular emissions and dust continuum properties. We will report the results obtained from this coordinated campaign.
The combined use of polarimetry, photometry, and spectroscopy in this coordinated observational effort provides an extensive characterization of the compositional and physical characteristics of 3I/ATLAS. This approach has produced constraints on the gas production rate, dust scattering, and overall activity of this interstellar object. In addition, a comparative study of 3I/ATLAS with comets from our solar system will provide insight into potential similarities and differences in composition and structure between these two types of objects. Thus, an increased understanding of both planet formation and cometary evolution can be achieved by comparing 3I/ATLAS with other cometary bodies throughout the galaxy. |
