Noted theoretical astrophysicist and a Padma Shri awardee, Professor Thanu Padmanabhan died due to cardiac arrest in Pune on Friday, a former colleague said. He was 64.

Padmanabhan suffered a cardiac arrest and was rushed to a hospital, where he died during treatment, sources said. Padmanabhan is survived by his wife and daughter. A distinguished professor at the Inter-University Centre for Astronomy and Astrophysics (IUCAA), Padmanabhan had conducted research on gravitation, structure formation in the universe and quantum gravity.

He wrote over 300 papers in international journals and also authored several books. "Today is one of the saddest days in the history of the Inter-University Centre for Astronomy & Astrophysics and the Indian scientific community. Professor Thanu Padmanabhan, a distinguished professor at IUCAA, passed away this morning as a result of a cardiac arrest," Somak Raychaudhury, director of IUCAA, said in a social media post.

The Kerala State Council for Science, Technology and Environment had recently awarded Padmanabhan the 'Kerala Sasthra Puraskaram', a lifetime achievement award. "Padmanabhan (known as Paddy to us all) leaves behind his wife and daughter, both distinguished astrophysicists, innumerable friends, admirers, colleagues, students and his monumental legacy of research in many fields of Physics and Astrophysics, and his incomparable textbooks and books of science for the general public," Raychaudhury said in the post.

K Vijay Raghavan, Principal Scientific Adviser to the Government of India, said in a tweet, “Shocked to hear of the passing of Professor Thanu Padmanabhan. His research linking general relativity and thermodynamics in new ways, and in other areas, has been widely recognized. Scholar, communicator, extraordinary scientist, friend to many. He will be much missed.”