2016/10/14 by Danielle M. Hastings, Darin Ragozzine, Daniel C. Fabrycky +9 · 1 citation
Mathematics · Physics and Astronomy · #Astro and Planetary Science #Astronomy #Astrophysics #Dwarf planet #Geometry #Mathematics #Orbital period #Photometry (optics) #Physics #Planet #Planetary Science and Exploration #Rotation (mathematics) #Rotation period #Spin (aerodynamics) #Stellar, planetary, and galactic studies #Tidal locking #astro-ph.EP
paper · pdf · doi:10.3847/0004-6256/152/6/195
published as 2016 AJ 152 195 · 21 pages with 6 figures, to be published in The Astronomical Journal
arxiv created 2016/10/14 · openalex publication_date 2016/11/28 · arxiv updated 2017/01/12 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/05
ABSTRACT Hi’iaka is the larger outer satellite of the dwarf planet Haumea. Using relative photometry from the Hubble Space Telescope and Magellan and a phase dispersion minimization analysis, we have identified the rotation period of Hi’iaka to be ∼9.8 hr (double peaked). This is ∼120 times faster than its orbital period, creating new questions about the formation of this system and possible tidal evolution. The rapid rotation suggests that Hi’iaka could have a significant obliquity and spin precession that could be visible in light curves within a few years. We then turn to an investigation of what we learn about the (currently unclear) formation of the Haumea system and family based on this unexpectedly rapid rotation rate. We explore the importance of the initial semimajor axis and rotation period in tidal evolution theory and find that they strongly influence the time required to despin to synchronous rotation, relevant to understanding a wide variety of satellite and binary systems. We find that despinning tides do not necessarily lead to synchronous spin periods for Hi’iaka, even if it formed near the Roche limit. Therefore, the short rotation period of Hi’iaka does not rule out significant tidal evolution. Hi’iaka’s spin period is also consistent with formation near its current location and spin-up due to Haumea-centric impactors.