Synchronous Rotation in the (120347) Salacia-Actaea System
Authors:
- Cameron CollyerCCCameron Collyer
- Jose Luis OrtizJOJose Luis Ortiz
- Bryan J. HollerBHBryan J. Holler
- Benjamin ProudfootBPBenjamin Proudfoot
- Nicolas MoralesNMNicolas Morales
- Rafael MoralesRMRafael Morales
- Susan BenecchiSBSusan Benecchi
- Flavia L. RommelFRFlavia L. Rommel
- Will GrundyWGWill Grundy
- Darin RagozzineDRDarin Ragozzine
Preprint
Abstract
We report on roughly 16 years of photometric monitoring of the transneptunian binary system (120347) Salacia-Actaea which provides significant evidence that Salacia and Actaea are tidally locked to the mutual orbital period in a fully synchronous configuration. The orbit of Actaea is updated, followed by a Lomb-Scargle periodogram analysis of the ground-based photometry which reveals a synodic period similar to the orbital period and a peak-to-peak lightcurve amplitude of δm = 0.0900 {\pm} 0.0036 mag (1σ uncertainty). Incorporating archival HST photometry that resolves each component, we argue that the periodicity in the unresolved data is driven by a longitudinally varying surface morphology on Salacia, and derive a sidereal rotation period that is within 1σ of the mutual orbital period. A rudimentary tidal evolution model is invoked that suggests synchronization occurred within 1.1 Gyr after Actaea was captured/formed.Keywords
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