一个原行星盘从它的出生包裹的发展
Dan M Watson1, C J Bohac, C Hull
1Department of Physics and Astronomy, University of Rochester, Rochester, New York 14627-0171, USA. dmw@pas.rochester.edu
Nature
|August 31, 2007
概括
天文学家观察了年轻的原星NGC 1333-IRAS 4B的水排放,揭示了形成原行星盘的细节. 这一发现提供了对年轻恒星物体周围行星形成早期阶段的见解.
科学领域:
- 天文学和天体物理学
- 恒星的形成和进化
- 外系行星科学 外系行星科学
背景情况:
- 0类原星是年轻恒星物体的早期阶段,对于理解原行星盘的形成至关重要.
- 之前的研究表明,NGC 1333-IRAS 4等原恒星内的更热,更密集的区域,但缺乏详细的观测.
- 毫米波长的观测显示了原恒星外中崩的动力学特征.
研究的目的:
- 在太阳系尺度上研究原多重系统NGC 1333-IRAS 4的核心结构.
- 检测和分析0类原星的嵌入区域内的气体组成.
- 观测一个原行星盘的早期发展.
主要方法:
- 在NGC 1333-IRAS 4B的中红外观测 (20-37微米).
- 对分子线排放的分析,特别是水 (H2O).
- 对观测到的排放进行建模,以推断气体特性和气体落入动态.
主要成果:
- 从NGC 1333-IRAS 4B中检测出一个丰富的H2O发射光谱.
- 排放源自极其密集和热的气体.
- 这些数据支持一个落入一个深深嵌入的,密集的磁盘的模型,表明原行星磁盘的发展.
- 这是30个样本中的唯一一个0类物体,显示了这种中红外线水辐射.
结论:
- 这些观测提供了围绕0类原星形成的原行星盘的直接证据.
- 独特的检测可能是由于有利的方向或代表一个短暂的进化阶段.
- 这项研究为行星形成的关键早期阶段提供了罕见的见解.
相关概念视频
02:06Conditions on Early Earth
Around 4 billion years ago, oceans began to condense on earth while volcanic eruptions released nitrogen, carbon dioxide, methane, ammonia, and hydrogen into the primordial atmosphere. However, organisms with the characteristics of life were not initially present on earth. Scientists have used experimentation to determine how organisms evolved that could grow, reproduce, and maintain an internal environment.
02:06Conditions on Early Earth
Around 4 billion years ago, oceans began to condense on earth while volcanic eruptions released nitrogen, carbon dioxide, methane, ammonia, and hydrogen into the primordial atmosphere. However, organisms with the characteristics of life were not initially present on earth. Scientists have used experimentation to determine how organisms evolved that could grow, reproduce, and maintain an internal environment.
01:10Kepler's First Law of Planetary Motion
In the early 17th century, German astronomer and mathematician Johannes Kepler postulated three laws for the motion of planets in the solar system. He formulated his first two laws based on the observations of his forebears, Nikolaus Copernicus and Tycho Brahe.
Polish astronomer Nikolaus Copernicus put forth a theory that stated a heliocentric model for the solar system. According to this heliocentric theory, all the planets, including Earth, orbit the Sun in circular orbits.
On the other hand,...
Polish astronomer Nikolaus Copernicus put forth a theory that stated a heliocentric model for the solar system. According to this heliocentric theory, all the planets, including Earth, orbit the Sun in circular orbits.
On the other hand,...
01:29Kepler's Second Law of Planetary Motion
In the early 17th century, German astronomer and mathematician Johannes Kepler postulated three laws for the motion of planets in the solar system. His first law states that all planets orbit the Sun in an elliptical orbit, with the Sun at one of the ellipse's foci. Therefore, the distance of a planet from the Sun varies throughout its revolution around the Sun.
While in an elliptical orbit, the total energy of the planet is conserved. Therefore, the planet slows down when it is at apogee and...
While in an elliptical orbit, the total energy of the planet is conserved. Therefore, the planet slows down when it is at apogee and...
01:18Kepler's Third Law of Planetary Motion
In the early 17th century, German astronomer and mathematician Johannes Kepler postulated three laws for the motion of planets in the solar system. In 1909, he formulated his first two laws based on the observations of his forebears, Nikolaus Copernicus and Tycho Brahe. However, in 1918, he published his third law of planetary motion, which gives a precise mathematical relationship between a planet's average distance from the Sun and the amount of time it takes to revolve around the Sun. It...
01:17Design Example: Calculating Safe Diameter for Wind-Exposed Disc
Assessing safety in wind-exposed installations is crucial to preventing potential failures. This example explores the calculation and design adjustments needed to mount a circular disc on a building facade, where wind forces are a primary concern. A 4-meter diameter disc was initially designed as an aesthetic feature facing winds at a velocity of 25 meters per second, with an air density of 1.25 kilograms per cubic meter. Given these conditions, the drag force on the disc was determined using...