Lead researcher Sabina Sagynbayeva of Stony Brook University explained that many exoplanet studies assume stars are evenly bright disks. "But we know just by looking at our own Sun that stars are more complicated than that," she said. The new model estimates the number, location, and brightness of stellar spots, improving knowledge of both stars and their planets.
Transit light curves usually show smooth dips when planets block starlight. However, smaller peaks and troughs can signal dark surface features similar to sunspots. These variations affect planetary measurements such as size, orbit, and temperature. By incorporating stellar rotation into the analysis, Sagynbayeva's team refined how spot patterns are mapped.
The researchers tested the approach on TOI 3884 b, a gas giant five times Earth's size and 32 times its mass, orbiting a cool star about 141 light-years away in Virgo. Their results suggest the star has dense spot regions near its north pole, which tilts toward Earth.
Co-author Brett Morris of the Space Telescope Science Institute noted that distinguishing between star and planet signals is critical. "If we want to look for water in the atmospheres of planets around those stars - a key indicator of habitability - we better be very sure that we're not confusing the two," he said.
NASA's upcoming Pandora mission, part of the Astrophysics Pioneers Program, will use tools like this to study exoplanet atmospheres and stellar activity with multiwavelength observations. "While Pandora will study about 20 worlds, it will advance our ability to pick out which signals come from stars and which come from planets," said TESS project scientist Allison Youngblood.
Research Report:Polka-dotted Stars: A Hierarchical Model for Mapping Stellar Surfaces Using Occultation Light Curves and the Case of TOI-3884
Related Links
NASA/Goddard Space Flight Center
Lands Beyond Beyond - extra solar planets - news and science
Life Beyond Earth
| Subscribe Free To Our Daily Newsletters |
| Subscribe Free To Our Daily Newsletters |
