A hot Jupiter orbiting a 2-million-year-old solar-mass T Tauri star

Area of Science:

• Exoplanetary science
• Stellar astrophysics
• Planet formation and evolution

Background:

• Hot Jupiters are giant exoplanets orbiting close to their host stars.
• Their inward migration mechanism and timing (early in protoplanetary disks vs. later interactions) remain unclear.
• Detecting hot Jupiters around young stars is challenging due to intense stellar magnetic activity.

Purpose of the Study:

• To investigate the formation and migration of hot Jupiters around young stars.
• To determine if hot Jupiters can form and migrate inwards early in a star's life.
• To confirm the presence of a hot Jupiter around the young star V830 Tau.

Main Methods:

• Radial velocity measurements of the young star V830 Tau.
• Filtering of stellar magnetic activity signals from the radial velocity data.
• Analysis of the radial velocity signal to detect periodic variations indicative of a planet.

Main Results:

• A periodic radial velocity signal with a 4.93-day period was detected in V830 Tau, unrelated to its rotation.
• This signal, with a false-alarm probability < 0.03%, indicates a planet of 0.77 Jupiter masses.
• The planet orbits at 0.057 AU, confirming the presence of a hot Jupiter around a young star.

Conclusions:

• Hot Jupiters can form and migrate inwards very early in planetary system evolution, within two million years.
• Planet-disk interactions are a likely mechanism driving this rapid inward migration.
• This discovery provides crucial evidence for early hot Jupiter formation and migration scenarios.