Who was Bibha Chowdhuri? The question has found a new audience in recent years, as the pioneering Indian physicist's life has entered school textbooks and her name has been given to a star. Yet for much of her life, Chowdhuri worked in the shadows of Indian science, her contributions recognised far less widely than those of her male contemporaries.
Chowdhuri was one of India's earliest particle and cosmic-ray physicists, a scientist whose work took her from laboratories in Kolkata to high-altitude experiment stations in the Himalayas. Her most notable contribution was her work on the pi-meson, a subatomic particle whose discovery was central to the development of modern particle physics.
The story begins in the 1940s, when Chowdhuri worked with her mentor, physicist D. M. Bose, at the Bose Institute in Kolkata. Together, they set out to search for a particle predicted by Japanese physicist Hideki Yukawa, a particle thought to carry the force that holds the nucleus of an atom together. To find it, they needed to study cosmic rays, high-energy particles from space that rain down on Earth and leave tracks in specially prepared photographic plates.
Chowdhuri played an instrumental role in those experiments. She helped set up stations at Darjeeling, Sandakphu and in Tibet, at altitudes of around 7,000 feet, 12,000 feet and 14,500 feet respectively, where cosmic radiation is stronger and clearer. Emulsion plates were exposed to cosmic radiation at those stations for periods of 150 to 202 days, then transported back to the institute for examination.
Chowdhuri travelled between the stations, often on horseback, carrying the plates and examining the tracks left by cosmic-ray particles.
The work was painstaking and physically demanding. The plates had to be handled with care, the tracks measured and interpreted, and the results checked and rechecked. But it produced results. Chowdhuri and Bose published their findings in the journal Nature, reporting evidence of the pi-meson in cosmic-ray experiments. It was a significant achievement, placing Indian researchers at the forefront of a field that was then dominated by laboratories in Europe and America.
Yet recognition did not follow in the way it might have. The Nobel Prize for work on the pi-meson went to others, and Chowdhuri's role in the early experiments was not widely acknowledged at the time.
As the director of the Inter-University Centre for Astronomy and Astrophysics, Somak Raychaudhury, later put it, Chowdhuri discovered a new subatomic particle, the pi-meson, from experiments in Darjeeling with her mentor D. M. Bose, published her results in Nature, but did not get due recognition.
Accounts of her life in the NCERT textbook chapter devoted to her say that she was nominated for a Nobel Prize in 1950 by physicist Erwin Schrödinger, though the nomination was unsuccessful. Whether or not that nomination is the full story, it reflects the regard in which her talent was held by at least some of the leading physicists of her time. What is not in doubt is that she never received major awards during her lifetime, and continued her work regardless.
In 1949, on her return to India after further study, Chowdhuri became the first woman faculty member at the Tata Institute of Fundamental Research in Mumbai, personally selected by its founder, Homi J. Bhabha. It was a landmark appointment, breaking new ground for women in Indian science at a time when research institutions were almost entirely male.
Her career continued across India's leading research institutions. She worked at the Physical Research Laboratory in Ahmedabad, under the mentorship of Vikram Sarabhai, and at the Saha Institute of Nuclear Physics in Kolkata. She also worked on experiments at the Kolar Gold Fields, where deep underground laboratories offered a shielded environment for studying cosmic rays and subatomic particles.
Through decades of research, she remained committed to her field, publishing papers and attending seminars and conferences long after many of her contemporaries had retired.
She continued working in high-energy physics until close to the end of her life, collaborating with the Saha Institute, the Indian Association for the Cultivation of Science and the University of Calcutta, and using the Variable Energy Cyclotron Centre's particle accelerator. Her last paper was published in 1990, a year before her death in 1991. By then, her name had largely faded from public memory.
The revival of her reputation began with a star. In 2019, as part of its centenary celebrations, the Paris-based International Astronomical Union invited countries around the world to name a star and its exoplanet through a global contest called NameExoWorlds. India was allotted a yellow-white dwarf star in the constellation Sextans, about 340 light years away, known to astronomers as HD 86081, and its Jupiter-like exoplanet, HD 86081b.
Indian school and college students were invited to suggest names, and around 1,717 entries were received. A national committee, working with the Astronomical Society of India, shortlisted ten names for public voting, and the final entry was selected after voting by more than 5,000 people. On December 17, 2019, the International Astronomical Union announced that the star would be called Bibha, in honour of Bibha Chowdhuri, and its planet would be known as Santamasa.
The names were chosen with care. Bibha means "a beam of light" in Bengali, a fitting tribute to a physicist who studied the light of cosmic rays and whose work illuminated a new area of physics. Santamasa is a Sanskrit term meaning "clouded", reflecting the cloudy nature of the exoplanet's atmosphere. Together, the two names were intended to symbolise the physical and lighting conditions of the distant planetary system.
The honour was widely reported in India at the time, and it brought Chowdhuri's story to a new generation. Newspapers described her as an unsung Indian physicist, and commentators noted the poignancy of a scientist who had spent her life studying the sky now having her name written in it.
That new recognition has since entered the classroom. The NCERT Class 8 English textbook includes a chapter titled "Bibha Chowdhuri: The Beam of Light that Lit the Path for Women in Indian Science", which tells her story for school students. The chapter describes her as a scientist who was often on the cusp of greatness but remained in the shadows of her male counterparts, and presents her life as an example for young women considering careers in science.
The inclusion matters because it addresses a wider gap. Women remain underrepresented in senior positions in Indian science, and the history of the field has often overlooked the contributions of women researchers. By teaching Chowdhuri's story, the textbook offers students a different model: a woman who pursued difficult, field-based research, who worked across institutions, and who persisted without the awards and recognition that her work deserved.
Her story also speaks to the conditions under which early Indian science was done. The cosmic-ray experiments of the 1940s were carried out with limited resources, in remote locations, and with equipment that today would seem rudimentary. That Indian researchers could produce work published in Nature under those conditions is a measure of their ingenuity, and of Chowdhuri's own determination.
There is also a lesson in the delay. Chowdhuri died in 1991, her story largely untold. It took nearly three decades, and a global contest to name a star, for her name to reach a wide public. That gap between achievement and recognition is a familiar one for women in science, and it is part of why her story resonates today.
Today, the star Bibha shines in the constellation Sextans, invisible to the naked eye but present in the catalogues of astronomy. Its planet, Santamasa, orbits it in the dark. For those who know the story behind the names, they are more than astronomical labels. They are a belated acknowledgement of a physicist who spent her life looking upward, and who, in the end, became a star herself.
(Reporting based on Livemint and The Hindu.)