English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Global: Zendy Plus annual

Presents the access of premium content as premium feature

Premium Content

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Global: Zendy Plus monthly

Global: Zendy Tools annual

Global: Zendy Tools monthly

Global: Zendy Free Plan

Among the four known transneptunian dwarf planets, Haumea is an exotic, veryelongated, and fast rotating body. In contrast to the other dwarf planets, itssize, shape, albedo, and density are not well constrained. Here we reportresults of a multi-chord stellar occultation, observed on 2017 January 21.Secondary events observed around the main body are consistent with the presenceof a ring of opacity 0.5, width 70 km, and radius 2,287$_{-45}^{+75}$ km. TheCentaur Chariklo was the first body other than a giant planet to show a ringsystem and the Centaur Chiron was later found to possess something similar toChariklo's rings. Haumea is the first body outside the Centaur population witha ring. The ring is coplanar with both Haumea's equator and the orbit of itssatellite Hi'iaka. Its radius places close to the 3:1 mean motion resonancewith Haumea's spin period. The occultation by the main body provides aninstantaneous elliptical limb with axes 1,704 $\pm$ 4 km x 1,138 $\pm$ 26 km.Combined with rotational light-curves, it constrains Haumea's 3D orientationand its triaxial shape, which is inconsistent with a homogeneous body inhydrostatic equilibrium. Haumea's largest axis is at least 2,322 $\pm$ 60 km,larger than thought before. This implies an upper limit of 1,885 $\pm$ 80 kgm$^{-3}$ for Haumea's density, smaller and less puzzling than previousestimations, and a geometric albedo of 0.51 $\pm$ 0.02, also smaller thanprevious estimations. No global N$_2$ or CH$_4$ atmosphere with pressureslarger than 15 and 50 nbar (3-$\sigma$ limits), respectively, is detected.

The size, shape, density and ring of the dwarf planet Haumea from a stellar occultation