Polar Motion Dynamics on Slow-Rotating Venus: Signatures of Mantle Flow

Kód výsledku v IS VaVaI

<a href="https://www.isvavai.cz/riv?ss=detail&h=RIV%2F00216208%3A11320%2F25%3A10508369" target="_blank" >RIV/00216208:11320/25:10508369 - isvavai.cz</a>

Výsledek na webu

<a href="https://verso.is.cuni.cz/pub/verso.fpl?fname=obd_publikace_handle&handle=m-GBttTpCX" target="_blank" >https://verso.is.cuni.cz/pub/verso.fpl?fname=obd_publikace_handle&handle=m-GBttTpCX</a>

DOI - Digital Object Identifier

<a href="http://dx.doi.org/10.1029/2025AV001976" target="_blank" >10.1029/2025AV001976</a>

Jazyk výsledku

angličtina

Název v původním jazyce

Polar Motion Dynamics on Slow-Rotating Venus: Signatures of Mantle Flow

Popis výsledku v původním jazyce

With its 1 day lasting 243 days on Earth, Venus is the slowest-spinning planet in the Solar System and its rotational bulge is anomalously small. A rotational bulge stabilizes the orientation of planets. Having only a tiny stabilizer, the rotational pole of Venus has been expected to separate from the figure pole in response to mantle flow, which has been used to explain why both poles are observed to be 0.5 degrees apart. Here, we couple 3D mantle-convection simulations and polar motion dynamics to explore how mantle flow, and in particular surface mobilization, drives Venus&apos;s polar motion. We provide a predictive framework for polar motion on slow rotators and show that the spin/figure pole separation (or offset) follows a simple law: it scales with the figure-axis drift rate times the planet&apos;s Chandler period. Contrary to prior expectations, stronger internal loading does not amplify the offset, and the mantle-driven polar motion is smooth rather than wobbly, more similar to that of fast rotators. In models matching Venus&apos;s geoid, figure-axis drift rates reach only up to a few degrees/Myr, too slow compared to ca. 60 degrees/Myr that is needed to match the observed offset. We therefore exclude mantle convection as the cause of Venus&apos; spin and figure poles separation, and suggest that atmospheric and solid tides are not balanced instead.

Název v anglickém jazyce

Polar Motion Dynamics on Slow-Rotating Venus: Signatures of Mantle Flow

Popis výsledku anglicky

With its 1 day lasting 243 days on Earth, Venus is the slowest-spinning planet in the Solar System and its rotational bulge is anomalously small. A rotational bulge stabilizes the orientation of planets. Having only a tiny stabilizer, the rotational pole of Venus has been expected to separate from the figure pole in response to mantle flow, which has been used to explain why both poles are observed to be 0.5 degrees apart. Here, we couple 3D mantle-convection simulations and polar motion dynamics to explore how mantle flow, and in particular surface mobilization, drives Venus&apos;s polar motion. We provide a predictive framework for polar motion on slow rotators and show that the spin/figure pole separation (or offset) follows a simple law: it scales with the figure-axis drift rate times the planet&apos;s Chandler period. Contrary to prior expectations, stronger internal loading does not amplify the offset, and the mantle-driven polar motion is smooth rather than wobbly, more similar to that of fast rotators. In models matching Venus&apos;s geoid, figure-axis drift rates reach only up to a few degrees/Myr, too slow compared to ca. 60 degrees/Myr that is needed to match the observed offset. We therefore exclude mantle convection as the cause of Venus&apos; spin and figure poles separation, and suggest that atmospheric and solid tides are not balanced instead.

Druh

J_imp - Článek v periodiku v databázi Web of Science

CEP obor

—

OECD FORD obor

10500 - Earth and related environmental sciences

Projekt

<a href="/cs/project/GA22-20388S" target="_blank" >GA22-20388S: Vývoj vnějších slupek ledových měsíců z pohledu numerického modelování</a><br>

Návaznosti

P - Projekt vyzkumu a vyvoje financovany z verejnych zdroju (s odkazem do CEP)

Rok uplatnění

2025

Kód důvěrnosti údajů

S - Úplné a pravdivé údaje o projektu nepodléhají ochraně podle zvláštních právních předpisů

Název periodika

AGU Advances

ISSN

2576-604X

e-ISSN

2576-604X

Svazek periodika

6

Číslo periodika v rámci svazku

6

Stát vydavatele periodika

US - Spojené státy americké

Počet stran výsledku

13

Strana od-do

e2025AV001976

Kód UT WoS článku

001631420100001

EID výsledku v databázi Scopus

2-s2.0-105024096842