Exploring the stellar rotation of early-type stars in the LAMOST medium-resolution survey

Context. Stellar rotation significantly shapes the evolution of massive stars, yet the interplay of mass and metallicity remains elusive, limiting our capacity to construct accurate stellar evolution models and to better estimate the impact of rotation on the chemical evolution of galaxies. Aims. Ou...

Full description

Saved in:
Bibliographic Details
Published in:Astronomy and astrophysics (Berlin) 2024-09, Vol.689
Main Authors: Sun, Weijia, Chiappini, Cristina
Format: Article
Language:English
Subjects:
A stars
Acceleration
Angular momentum
Angular velocity
Astronomical models
Chemical evolution
Galactic rotation
Galaxies
Magellanic clouds
Massive stars
Metallicity
Parameter identification
Star & galaxy formation
Star formation
Stellar evolution
Stellar models
Stellar rotation
Online Access:Get full text
Tags: Add Tag
No Tags, Be the first to tag this record!
Description
Summary:Context. Stellar rotation significantly shapes the evolution of massive stars, yet the interplay of mass and metallicity remains elusive, limiting our capacity to construct accurate stellar evolution models and to better estimate the impact of rotation on the chemical evolution of galaxies. Aims. Our goal is to investigate how mass and metallicity influence the rotational evolution of A-type stars on the main sequence (MS). We seek to identify deviations in rotational behaviors that could serve as new constraints for existing stellar models. Methods. Using the LAMOST Median-Resolution Survey Data Release 9, we derived stellar parameters for a population of 104 752 A-type stars. Our study focused on the evolution of surface rotational velocities and their dependence on mass and metallicity in 84 683 “normal” stars. Results. Normalizing surface rotational velocities to zero age main sequence (ZAMS) values revealed a prevailing evolutionary profile from 1.7 to 4.0 M⊙. This profile features an initial rapid acceleration until t/tMS = 0.25 ± 0.1 and potentially a second acceleration peak near t/tMS = 0.55 ± 0.1 for stars heavier than 2.5 M⊙, followed by a steady decline and a “hook” feature at the end. Surpassing theoretical expectations, the initial acceleration likely stems from a concentrated distribution of angular momentum at the ZAMS, resulting in a prolonged increase in speed. A transition phase for stars with 2.0 
ISSN:0004-6361
1432-0746
DOI:10.1051/0004-6361/202450628