A giant planet transiting a 3-Myr protostar with a misaligned disk

Area of Science:

• Exoplanetary science
• Stellar and galactic astronomy

Background:

• Transiting planets around young stars (10-40 million years) are known, but planets around younger stars (<10 million years) have been elusive.
• Potential reasons for the elusiveness include incomplete planet formation or obscured views by protoplanetary disks.
• Warped or broken outer disks may allow for transiting planet visibility if inner disks are depleted.

Purpose of the Study:

• To report the discovery and characterization of a transiting planet around a very young pre-main-sequence star.
• To investigate the potential for observing planets in systems with misaligned disks.

Main Methods:

• Photometric observations to detect transits.
• Radial-velocity measurements to constrain the planet's mass.
• Analysis of stellar properties and disk inclination.

Main Results:

• Discovery of the transiting planet IRAS 04125+2902 b orbiting a 3-million-year-old star.
• The planet has a period of 8.83 days and a radius of 10.7 Earth radii.
• A 95% confidence upper mass limit of 90 Earth masses was determined, suggesting it could be a super-Earth or sub-Neptune precursor.

Conclusions:

• This discovery demonstrates the possibility of finding transiting planets around very young stars.
• The planet IRAS 04125+2902 b may represent an early stage in the formation of super-Earths and sub-Neptunes.
• The system exhibits disk-star misalignment, the origin of which requires further investigation.