Tidally locked rotation of the dwarf planet (136199) Eris discovered via long-term ground-based and space photometry

DOI: 
10.1051/0004-6361/202245234
Publication date: 
15/01/2023
Main author: 
Szakáts, R.
IAA authors: 
Ortiz, J. L.;Morales, N.;Santos-Sanz, P.;Duffard, R.
Authors: 
Szakáts, R.;Kiss, Cs.;Ortiz, J. L.;Morales, N.;Pál, A.;Müller, T. G.;Greiner, J.;Santos-Sanz, P.;Marton, G.;Duffard, R.;Sági, P.;Forgács-Dajka, E.
Journal: 
Astronomy and Astrophysics
Publication type: 
Article
Volume: 
669
Pages: 
L3
Abstract: 
The rotational states of the members in the dwarf planet-satellite systems in the trans-Neptunian region are determined by formation conditions and the tidal interaction between the components. These rotational characteristics serve as prime tracers of their evolution. A number of authors have claimed a very broad range of values for the rotation period for the dwarf planet Eris, ranging from a few hours to a rotation that is (nearly) synchronous with the orbital period (15.8 d) of its satellite, Dysnomia. In this Letter, we present new light curve data for Eris, taken with ∼1-2 m-class ground based telescopes and with the TESS and Gaia space telescopes. The TESS data did not provide a well-defined light curve period, but it could be used to constrain light curve variations to a maximum possible light curve amplitude of Δm ≤ 0.03 mag (1-σ) for P ≤ 24 h periods. Both the combined ground-based data and Gaia measurements unambiguously point to a light curve period equal to the orbital period of Dysnomia, P = 15.8 d, with a light curve amplitude of Δm ≈ 0.03 mag, indicating that the rotation of Eris is tidally locked. Assuming that Dysnomia has a collisional origin, calculations with a simple tidal evolution model show that Dysnomia must be relatively massive (mass ratio of q = 0.01-0.03) and large (radius of R<SUB>s</SUB> ≥ 300 km) to have the potential to slow Eris down to a synchronised rotation. These simulations also indicate that (assuming tidal parameters usually considered for trans-Neptunian objects) the density of Dysnomia should be 1.8-2.4 g cm<SUP>−3</SUP>. This is an exceptionally high value among similarly sized trans-Neptunian objects, setting important constraints on their formation conditions. <P />Full Tables A.1., A.2., A.4 are only available at the CDS via anonymous ftp to <A href="http://cdsarc.cds.unistra.fr">cdsarc.cds.unistra.fr</A> (ftp://130.79.128.5) or via <A href="https://cdsarc.cds.unistra.fr/viz-bin/cat/J/A+A/669/L3">https://cdsarc.cds.unistra.fr/viz-bin/cat/J/A+A/669/L3</A>
Database: 
ADS
SCOPUS
URL: 
https://ui.adsabs.harvard.edu/#abs/2023A&A...669L...3S/abstract
ADS Bibcode: 
2023A&A...669L...3S
Keywords: 
Kuiper belt objects: individual: (136199) Eris;methods: observational;techniques: photometric;Astrophysics - Earth and Planetary Astrophysics