Create accountLogin

Recent searches

No recent searches

Search options

Only available when logged in.
veganism.social is one of the many independent Mastodon servers you can use to participate in the fediverse.
Veganism Social is a welcoming space on the internet for vegans to connect and engage with the broader decentralized social media community.

Administered by:

Server stats:

265
active users

veganism.social: AboutStatusProfiles directoryPrivacy policy

Mastodon: AboutGet the appKeyboard shortcutsView source codev4.4.0-alpha.5

#rotation

1 post1 participant1 post today
Public
Mikko Tuomi

Characterising the stellar differential #rotation based on largest-spot statistics from ground-based #photometry.

We model the statistics of the dominating #spots of two young and active Solar-type stars, V889 Her and LQ Hya, in order to obtain information on the underlying spot distribution, rotation of the #star, as well as the orientation of the stellar axis of spin.

#astronomy #astrophysics
arxiv.org/abs/2410.06076

arXiv.orgCharacterising the stellar differential rotation based on largest-spot statistics from ground-based photometryStellar spot distribution has consequences on the observable periodic signals in long-time baseline ground-based photometry. We model the statistics of the dominating spots of two young and active Solar-type stars, V889 Her and LQ Hya, in order to obtain information on the underlying spot distribution, rotation of the star, as well as the orientation of the stellar axis of spin. By calculating estimates for spot-induced periodicities in independent subsets of photometric data, we obtain statistics based on the dominating spots in each subset, giving rise to largest-spot statistics accounting for stellar geometry and rotation, including differential rotation. Our simple statistical models are able to reproduce the observed distribution of photometric signals rather well. This also enables us to estimate the dependence of angular velocity of the spots as a function of latitude. Our results indicate that V889 Her has a non-monotonic differential rotation curve with a maximum angular velocity between latitudes of 37-40 deg and lower angular velocity at the pole than the equator. Our results for LQ Hya indicate that the star rotates much like a rigid body. Furthermore, the results imply that the monotonic Solar differential rotation curve may not be a universal model for other solar-type stars. The non-monotonicity of the differential rotation of V889 Her is commonly produced in magnetohydrodynamic simulations, which indicates that our results are realistic from a theoretical perspective.
Public
Mikko Tuomi

The sun rotates the fastest at the equator, whereas the #rotation rate slows down at higher latitudes and is the slowest at the polar regions.

But a nearby sun-like star—V889 Herculis, some 115 light years away in the constellation of Hercules—rotates the fastest at a latitude of about 40 degrees, while both the equator and polar regions rotate more slowly.

Such a behavior has never been observed for any #star, and we have no idea what is going on.

#astronomy
phys.org/news/2024-07-astronom

Phys.org · Astronomers find anomalies in star V889 Herculis's rotationBy Johanna Pellinen
VegansExploreLive feeds
About