Anomalously fast core and envelope rotation in red giants

Fuente: arXiv
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Autori principali: Dhanpal, Siddharth, Benomar, Othman, Hanasoge, Shravan, Fuller, Jim
Natura: Preprint
Pubblicazione: 2025
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author Dhanpal, Siddharth
Benomar, Othman
Hanasoge, Shravan
Fuller, Jim
author_facet Dhanpal, Siddharth
Benomar, Othman
Hanasoge, Shravan
Fuller, Jim
contents Red giants undergo dramatic and complex structural transformations as they evolve. Angular momentum is transported between the core and envelope during this epoch, a poorly understood process. Here, we infer envelope and core rotation rates from Kepler observations of $\sim$1517 red giants. While many measurements are consistent with the existing studies, our investigation reveals systematic changes in the envelope-to-core rotation ratio and we report the discovery of anomalies such as clump stars with rapidly rotating cores, and red giants with envelopes rotating faster than their cores. We propose binary interactions as a possible mechanism by which some of these cores and envelopes are spun up. These results pose challenges to current theoretical expectations and can have major implications for compact remnants born from stellar cores.
format Preprint
id arxiv_https___arxiv_org_abs_2506_06415
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Anomalously fast core and envelope rotation in red giants
Dhanpal, Siddharth
Benomar, Othman
Hanasoge, Shravan
Fuller, Jim
Solar and Stellar Astrophysics
Red giants undergo dramatic and complex structural transformations as they evolve. Angular momentum is transported between the core and envelope during this epoch, a poorly understood process. Here, we infer envelope and core rotation rates from Kepler observations of $\sim$1517 red giants. While many measurements are consistent with the existing studies, our investigation reveals systematic changes in the envelope-to-core rotation ratio and we report the discovery of anomalies such as clump stars with rapidly rotating cores, and red giants with envelopes rotating faster than their cores. We propose binary interactions as a possible mechanism by which some of these cores and envelopes are spun up. These results pose challenges to current theoretical expectations and can have major implications for compact remnants born from stellar cores.
title Anomalously fast core and envelope rotation in red giants
topic Solar and Stellar Astrophysics
url https://arxiv.org/abs/2506.06415