Nicholas Sorabella’s Research Could Aid in Discovery of Black Holes

Nick Sorabella Image by Brooke Coupal
Nicholas Sorabella examines the sky with a telescope inside the UML Schueller Observatory.

By Brooke Coupal

Nicholas Sorabella ’21 is helping others unlock the mysteries of the universe.

The physics Ph.D. student is developing an easily accessible tool that could lead to discoveries of black holes, neutron stars and white dwarfs. Sorabella’s research caught the attention of NASA, which recently awarded him a grant worth more than $47,000 through its FINESST (Future Investigators in NASA Earth and Space Science and Technology) program.

“One of NASA’s main missions is the understanding of the universe,” says Antonino Cucchiara, the lead program scientist for FINESST’s Astrophysics Division. “Nicholas’ work will be monumental in our advancement not only of the science but also because it will provide a powerful tool that will enable new discoveries after the grant is over.”

The highly competitive grant program accepted 10% of applicants in the Astrophysics Division this year, Cucchiara says.

“The grant lets me focus entirely on my research for my last year as a Ph.D. student,” Sorabella says. “And it’s an honor to have the NASA logo behind it.”

Helping Everyday People Become Astronomers

After Sorabella was accepted into UMass Lowell’s physics graduate program, Assoc. Prof. Silas Laycock invited him to campus to talk about astronomy. Laycock told Sorabella about a puzzling binary system called IC 10 X-1, which consists of a black hole and a massive star. Scientists have been stumped trying to accurately calculate the mass of the pair.

“All the standard methods for measuring the masses of the star and the black hole had given a very strange result, which we thought couldn’t possibly be right for various technical reasons,” Laycock says.

Interested in finding a way to calculate the actual masses of the objects, Sorabella began to investigate. He learned of well-developed mathematics for a phenomenon known as gravitational self-lensing, in which a black hole acts as a magnifying glass when passing in front of a star, causing the star to appear brighter from our perspective. This lensing is a manifestation of Einstein's general theory of relativity.

“That was very intriguing to me,” Sorabella says. “From there, I started writing a computer code that could model this effect.”

Sorabella’s model can be used to discover black holes and additional gravitational self-lensing objects such as neutron stars and white dwarfs. Data from NASA’s Kepler Space Telescope and Transiting Exoplanet Survey Satellite on light curves, which show the brightness of a star over time, can be input into his code. Peaks in the light curve could indicate that a black hole, neutron star or white dwarf, all of which are dense objects, passed in front of another star, intensifying its brightness. From these peaks, the model can then give estimates of the dense object’s mass, radius and other parameters.

  • Nicholas Sorabella further explains his research in this UML Student Research & Community Engagement Symposium video.

Over the years, Sorabella, who got a master’s degree in physics from UML in 2021, has developed the code to model other astrophysical effects, including Doppler boosting, where a star appears brighter or dimmer depending on its orbital motion around a dense object, and ellipsoidal variations, where a dense object distorts the shape and brightness of the star.

Sorabella originally developed his code in the software system Mathematica but switched it over to the programming language Python with the help of recent alum Liam Neely ’23. 

“Python is the fastest growing programming language and it’s considered the most accessible because it’s free [unlike Mathematica], and it’s not too difficult to learn,” Sorabella says.

Nick Sorabella and Silas Laycock Image by Brooke Coupal
Assoc. Prof. Silas Laycock, right, encouraged Nicholas Sorabella, left, to apply to the NASA FINESST program.

Upon completion, he plans to launch his code on the hosting platform GitHub, along with tutorials on how to use it. He has named his tool the Self-lensing Model Involving Limb-darkened Ellipsoidals or SMILE for short. Last spring, Sorabella was named a Kennedy College of Sciences graduate winner in the Student Research & Community Engagement Symposium for his presentation on SMILE.

“I want the code to be publicly available and friendly,” he says. “SMILE is an easy-to-use tool designed for someone who has very little coding knowledge.”

Sorbella is enthusiastic about making astrophysics more accessible to others.

“This tool gives citizen scientists the opportunity to find potential black holes and other compact objects,” he says.

Laycock, who serves as Sorabella’s Ph.D. advisor, says he’s proud of the work Sorabella is doing.

“Nick is not just interested in astronomy. He’s somebody who’s really willing to do the leg work,” he says. “He has a great career in astrophysics ahead of him.”