Mass measurements of infant planets orbiting the young star V1298 Tau

The infant star V1298 Tau, only about 20 million years old, hosts a system of four transiting planets. Determining the masses of these young worlds is essential for understanding how planetary systems form and evolve. Recent observations have provided updated mass constraints for these planets by monitoring the star over four and a half years to detect the subtle gravitational wobbles they induce on their host.

Researchers analyzed over 380 high-resolution spectra to measure the radial velocity of the star—the slight back-and-forth movement caused by the gravitational tug of orbiting planets. Because young stars are magnetically active and show high levels of surface variability, the team utilized advanced statistical techniques and simulations to filter out stellar noise from the signals.

The findings indicate that planets V1298 Tau b and V1298 Tau e have masses consistent with gas giants. These mass estimates are notably higher than previous calculations that relied solely on transit timing variations, which had suggested these worlds were extremely low-density or "super-puffy." For the two smaller planets, V1298 Tau c and V1298 Tau d, the study provides updated upper limits on their possible mass.

Key findings
- Masses for planets V1298 Tau b and V1298 Tau e were measured as being consistent with giant planets.
- New mass estimates for planets b and e are higher than those previously predicted by transit timing studies.
- Updated mass upper limits were established for the remaining two planets in the system, c and d.
- Advanced noise-filtering techniques were required to isolate planet signals from the intense magnetic activity of the young host star.

Scientific study

The GAPS programme at TNG LXXIX. New mass constraints for the infant planets in the V1298 Tau system through a long-term radial velocity monitoring with HARPS-N (external link)