関連する実験動画
Updated: May 4, 2026

06:48
Surface Mapping of Earth-like Exoplanets using Single Point Light Curves
Published on: May 10, 2020
3.0K
ネプテュンの5つの不規則な衛星の発見
Matthew J Holman1, J J Kavelaars, Tommy Grav
1Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, Massachusetts 02138, USA. mholman@cfa.harvard.edu
Nature
|August 20, 2004
まとめ
天文学者は,海王星を周回する5つの新しい不規則な衛星を発見しました. これらの微弱で捕捉された衛星は,海王星に関する私たちの理解を広げています.
科学分野:
- 惑星科学は惑星科学である.
- 天文学 天文学
- 太陽系ダイナミクス 太陽系ダイナミクス
背景:
- 巨大惑星には,定期的な月と不定期的な月がある.
- ネプテュンの不規則な衛星であるトリトンとネレイドは,異常な特徴を示しています.
- トリトンの逆行軌道とネレイドの高度な奇心性は,複雑な捕獲の歴史を示唆しています.
研究 の 目的:
- ネプテュンの不規則な衛星システムの組成を調べるために.
- ネプテュンの新しい不規則な衛星を発見し,特徴づけること.
- 衛星の捕捉と巨大惑星の周りの軌道動態のモデルを精査する.
主な方法:
- 先進的な望遠鏡を用いた深空画像調査.
- フォトメトリック分析により,表面の大きさと色を決定する.
- 繰り返された観測による軌道決定.
主要な成果:
- ネプテュンの5つの新しい不規則な衛星の発見.
- 2つの進行軌道と3つの逆行軌道が特定されました.
- 月は薄弱 (m(R) = 24.2-25.4) で,直径は30〜50キロメートルと推定されています.
- これらの発見は,これまで考えられていたよりも複雑な捕獲プロセスを示唆しています.
結論:
- ネプテュンの不規則な月系は,これまで知られていたよりも広大です.
- 新しく発見された衛星は,おそらく海王星によって捕らえられた.
- これらの衛星の捕捉メカニズムと進化の歴史を理解するためにさらなる研究が必要です.
関連する概念動画
Newman Projections
16.9K
Different notations are used to represent the three-dimensional structure of molecules on two-dimensional surfaces. One of the most commonly used representations is the dash-wedge formula. The dashed wedges, solid wedges, and the plane lines indicate the groups situated behind the plane, coming out of the plane, and in the plane, respectively.
The organic molecules rotate across the single bonds leading to numerous temporary three-dimensional structures of varying energy known as...
The organic molecules rotate across the single bonds leading to numerous temporary three-dimensional structures of varying energy known as...
16.9K
Circular Orbits and Critical Velocity for Satellites
2.9K
The Moon orbits around the Earth. In turn, the Earth (and other planets) orbit the Sun. The space directly above our atmosphere is filled with artificial satellites in orbit. One can examine the circular orbit, the simplest kind of orbit, to understand the relationship between the speed and the period of planets and satellites with respect to their positions and the bodies that they orbit.
Nicolaus Copernicus (1473-1543) first suggested that the Earth and all other planets orbit the Sun in...
Nicolaus Copernicus (1473-1543) first suggested that the Earth and all other planets orbit the Sun in...
2.9K
Kepler's First Law of Planetary Motion
4.9K
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,...
4.9K
Kepler's Second Law of Planetary Motion
4.7K
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...
4.7K
Kepler's Third Law of Planetary Motion
3.6K
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...
3.6K
Gravitation
8.4K
In the years before Newton, a general belief prevailed that different laws governed objects in the sky than objects on Earth. When Kepler wrote down the three laws of planetary motion, explaining in detail the geometrical properties of the planetary orbits around the Sun, there was no immediate idea to discern their connection with more fundamental laws. It was Isaac Newton who, in 1665–66, figured out the connection between planetary motion, the motion of the moon around the Earth, and...
8.4K

