Transiting extrasolar planetary candidates in the Galactic bulge.

Area of Science:

• Astronomy and Astrophysics
• Exoplanetary Science

Background:

• Over 200 extrasolar planets detected via Doppler shifts and transits.
• Transit surveys typically focus on stars more massive than 0.75 solar masses (M☉).
• Short-period planets (1.2-2.5 days) are primarily found through transit surveys.

Purpose of the Study:

• To conduct a planetary transit search in a dense stellar field toward the Galactic bulge.
• To identify exoplanet candidates, particularly those with short orbital periods.
• To investigate the characteristics of planets orbiting low-mass stars.

Main Methods:

• Performed a transit survey in a rich stellar field.
• Analyzed transit data to identify potential exoplanet candidates.
• Utilized radial-velocity measurements to confirm planetary nature in select cases.

Main Results:

• Discovered 16 exoplanet candidates with orbital periods ranging from 0.4 to 4.2 days.
• Identified five candidates orbiting stars with masses between 0.44 and 0.75 M☉.
• Confirmed two candidates as planets using radial-velocity measurements.
• Found five ultra-short-period planets (orbital period < 1.0 day) around stars less massive than 0.88 M☉.

Conclusions:

• Introduced a new class of ultra-short-period planets orbiting low-mass stars.
• Hypothesized that planets near luminous stars may be destroyed by evaporation.
• Suggested that jovian planets might migrate to smaller radii around lower-mass stars.