相关实验视频
Updated: May 26, 2026

06:42
Magnetically Induced Rotating Rayleigh-Taylor Instability
Published on: March 3, 2017
红巨星中的快速核心旋转是由重力主导的混合模式揭示出来的
Paul G Beck1, Josefina Montalban, Thomas Kallinger
1Instituut voor Sterrenkunde, Katholieke Universiteit Leuven, 3001 Leuven, Belgium. paul.beck@ster.kuleuven.be
Nature
|December 14, 2011
概括
红巨星的核心的旋转速度比它们的表面更快. 这项研究使用恒星振荡模式揭示了旋转形状的急剧梯度,证实了关于恒星内部的理论预测.
科学领域:
- 天文学 天文学
- 恒星天体物理学 恒星天体物理学
- 天文地震学/天文地震学
背景情况:
- 红巨星是在核心耗尽后形成的,其特点是核心收缩和膨胀,冷却的外.
- 角度动量的保存预测这些恒星的核心旋转速度比外旋转快,得到间接证据的支持.
- 直接观察内部角动量分布是具有挑战性的.
研究的目的:
- 为了研究红巨星的内部旋转速度.
- 为了确定从表面到核心的角运动量分布.
- 为了测试恒星内部旋转的理论预测.
主要方法:
- 分析来自恒星振荡的"混合模式".
- 测量振荡模式的旋转频率分割.
- 与理论上的恒星进化和旋转模型进行比较.
主要成果:
- 在红巨星中观察到从恒星表面向核心的旋转率增加.
- 确定核心的旋转速度至少是表面的十倍.
- 在内部旋转配置文件中检测到一个的梯度.
结论:
- 这项研究提供了观察证据,证明红巨星中旋转速度明显更快的核心存在.
- 这一发现证实了理论上对的内部旋转梯度的预测.
- 星体地震学提供了一种强大的工具,可以探测难以接近的恒星内部属性.
相关概念视频
Gravitation Between Spherically Symmetric Masses
The gravitational potential energy between two spherically symmetric bodies can be calculated from the masses and the distance between the bodies, assuming that the center of mass is concentrated at the respective centers of the bodies.
Apparent Weight and the Earth's Rotation
Since all objects on the Earth's surface move through a circle every 24 hours, there must be a net centripetal force on each object, directed towards the center of that circle. The points of the north and south poles are the only exception to this rule.
For an object on the Earth's equator, the net centripetal force that accounts for its rotation is the Earth's pull towards its center, or the weight minus the normal force that prevents it from piercing into the Earth's surface. This force,...
For an object on the Earth's equator, the net centripetal force that accounts for its rotation is the Earth's pull towards its center, or the weight minus the normal force that prevents it from piercing into the Earth's surface. This force,...
Atomic Nuclei: Larmor Precession Frequency
The earth's gravitational field produces a 'twisting force' perpendicular to the angular momentum of a spinning mass (such as a spinning top) that causes the mass to 'wobble' around the gravitational field axis in a phenomenon called precession. Similarly, the magnetic moment (μ) of a spinning nucleus precesses due to an external magnetic field directed along the z-axis. The precession of the magnetic moment vector about the magnetic field is called Larmor precession, and the angular frequency...
Rotational Motion about a Fixed Axis
A rigid body's rotation around a fixed axis makes every point within it trace a circular path around a specific line or point. The term given to this type of spinning is defined by the angular position, symbolized by the angle θ. This angle is gauged from a static reference line to the revolving object. From this angular position, any variation is referred to as angular displacement, denoted by dθ. The extent of this displacement can be calculated in degrees, radians, or revolutions, where one...
Equation of Rotational Dynamics
Angular variables are introduced in rotational dynamics. Comparing the definitions of angular variables with the definitions of linear kinematic variables, it is seen that there is a mapping of the linear variables to the rotational ones. Linear displacement, velocity, and acceleration have their equivalents in rotational motion, which are angular displacement, angular velocity, and angular acceleration. Similar to the rotational variables, a mapping exists from Newton's second law of motion...
Kinematic Equations for Rotation
In mechanics, when one observes a rigid body in rotational motion with constant angular acceleration, it is possible to establish equations for its rotational kinematics. This process resembles how linear kinematics are dealt with in simpler motion studies.
For instance, imagine a point A on a rigid body engaged in circular motion. The translational velocity of this particular point can be calculated by taking the time derivatives of the displacement equation, which essentially measures the...
For instance, imagine a point A on a rigid body engaged in circular motion. The translational velocity of this particular point can be calculated by taking the time derivatives of the displacement equation, which essentially measures the...

