ELFT HÍRADÓ

[vidakris AT konkoly.hu]

Szemináriumi meghívó / Invitation to a seminar
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CSFK CSI SZEMINÁRIUM / KONKOLY OBSERVATORY SEMINAR

Date: Mar 23, 2023 (Thursday) 14:00


Róbert Szakáts (Konkoly Observatory, CSFK, Hungary)
Tidally locked rotation of the dwarf planet (136199) Eris discovered via 
long-term ground-based and space photometry


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 o
 rbital 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 Rs ≥ 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-3. This is an 
exceptionally high value among similarly sized trans-Neptunian objects, 
setting important constraints on their formation conditions.


The seminar will be held live in the Detre hall with audience, but also 
streamed online via Zoom. If you are unable to attend the presentation in 
person, you can join us via this link
https://us06web.zoom.us/j/82806911982?pwd=SVZpT0syQ1J6dHBvSkF4N2dXNEQ0dz09
or the meeting ID: 828 0691 1982 and passcode: 206265



Everyone is welcome!

Krisztián Vida, Ramon Brasser
organizers
https://konkoly.hu/szeminar/szeminarium.shtml