2023/05/04 by Thea Faridani, Smadar Naoz, Faridani, Thea H. +5 · 3 citations
Physics and Astronomy · #Astronomy and Astrophysical Research #Earth and Planetary Astrophysics (astro-ph.EP) #FOS: Physical sciences #Scientific Research and Discoveries #Stellar, planetary, and galactic studies
paper · pdf · doi:10.48550/arxiv.2305.03104
openalex publication_date 2023/05/04 · openalex created_date 2023/05/10 · openalex updated_date 2026/08/01
Short and ultra-short planets are a peculiar type of exoplanets with periods as short as a few days or less. Although it is challenging to detect them, already several are observed with many additional candidates. If these planets have formation pathways to their longer period counterparts, they are predicted to reside in multi-planet systems. Thus, gravitational perturbation from potential planetary neighbors may affect their orbital configuration. However, due to their close proximity to their host star, they are also subjects to general relativity precession and torques from the stellar spin quadrupole moment (J2). Here we show that an evolving J2 due to magnetic braking, affects the magnitude and location of secular resonances of the short period planet in a multi-planet system. Thus, driving the short period planet into and out of a secular resonance, exciting the planet's eccentricity and inclination. The high inclination can hinder transit observation, and, in some cases, the high eccentricity may result in an unstable configuration. We propose that evolving J2 in a multi-planet system can be critical in understanding the detectability and stability of short-period planets.