Caltech Ph.D Student Viraj Karambelkar Selected for NASA Hubble Fellowship Program
- The Pune native’s research focuses on the study of time-domain and multi-messenger astronomy.
Viraj Karambelkar, a Ph.D student in the Astrophysics Department at California Institute of Technology (Caltech), is among 24 candidates selected for the highly competitive NASA Hubble Fellowship Program (NHFP). He was selected for his proposal titled “The Anthropology of Merging Stars.”
NASA says the fellowship “fosters excellence and leadership in astrophysics by supporting exceptionally promising and innovative early-career astrophysicists.” Each fellowship provides the awardee up to three years of support at a U.S. institution. Over 650 applications were received for the 2025 fellowships, NASA said.
“The 2025 class of the NASA Hubble Fellowship Program is comprised of outstanding NASA Astrophysics researchers,” said Shawn Domagal-Goldman, acting director of the Astrophysics Division at NASA Headquarters in Washington. “This class of competitively selected fellows will inspire future generations through the products of their research, and by sharing the results of that work with the public. Their efforts will help NASA continue its worldwide leadership in space-based astrophysics research.”
Karambelkar grew up in Pune and completed his bachelor’s in engineering physics and mathematics from the Indian Institute of Technology Bombay in 2019. He is currently a graduate student at the California Institute of Technology (Caltech), working with Mansi Kasliwal, and will complete his Ph.D this year.
His Ph.D research has “centered on improving our understanding of merging stars, merging white dwarfs, and merging neutron stars.” NASA said. Using a range of optical and infrared time-domain surveys, he has conducted systematic searches for the explosive, variable, and dusty outcomes of these cosmic mergers, leveraging them as probes of stellar processes, gravitational wave sources, and cosmic dust. He developed the transient-detection pipeline for the new infrared Wide-Field Infrared Transient Explorer (WINTER) surveyor at Palomar Observatory, and has led observing programs with the James Webb Space Telescope and the Hubble Space Telescope.
As a Hubble Fellow, Karambelkar will use “the exciting landscape of upcoming surveys,” including the Vera C. Rubin Observatory, NASA’s SPHEREx mission, and the Nancy Grace Roman Space Telescope, “to vastly expand the limited sample of stellar mergers and study them in unprecedented detail,” NASA said. His work will focus on using these discoveries to constrain the evolution of binary stars that eventually become gravitational wave sources, and quantify the impact of these mergers on the cosmic dust budget.