関連する実験動画
Updated: Apr 27, 2026
06:48
Surface Mapping of Earth-like Exoplanets using Single Point Light Curves
Published on: May 10, 2020
3.0K
エクソプラネット検出. M矮星 Gliese 581 の居住可能なゾーンにある惑星として仮装した恒星の活動
Paul Robertson1, Suvrath Mahadevan2, Michael Endl3
1Department of Astronomy and Astrophysics, The Pennsylvania State University, University Park, PA 16802, USA. Center for Exoplanets and Habitable Worlds, The Pennsylvania State University, University Park, PA 16802, USA. pmr19@psu.edu.
Science (New York, N.Y.)
|July 5, 2014
まとめ
以前は居住可能なゾーンにあると考えられていた惑星GJ 581dは,おそらく存在しない. 恒星の活動分析は,その信号が人工物であり,GJ 581gのような他の系外惑星の検出に影響を及ぼすことを示唆しています.
科学分野:
- 天文学と天体物理学について
- 惑星外科学とは,惑星外科学です.
- スターラ・アクティビティ スターラ・アクティビティ
背景:
- M型矮星であるGliese 581には4つの惑星があり,GJ 581dとGJ 581gは潜在的に居住可能なゾーンの系外惑星と考えられていた.
- GJ 581dとGJ 581gの存在と特徴は,軌道離心率と恒星の活動に関する仮定の影響を受け,議論の対象となっている.
研究 の 目的:
- 星の活動を分析することによって,グリーゼ581の周りの惑星信号を再評価する.
- GJ 581d信号の真の性質とその他の検出された系外惑星への影響を決定する.
主な方法:
- 星の自転周期を測定するためにHα線を用いた恒星活動の分析.
- 恒星汚染を特定し,修正するために,放射速度データとHα調節の相関.
- 惑星の信号を評価するために活動修正後に放射速度データを再分析する.
主要な成果:
- グリーゼ581の恒星回転周期は130±2日であった.
- 恒星の活動に対する補正により,GJ 581dの信号は標準偏差1.5に大幅に減少しました.
- 分析により,GJ 581dは恒星の活動による人工物である可能性が明らかになり,GJ 581gの誤った検出にもつながった.
結論:
- 外惑星GJ 581dは,本物の惑星信号として存在していないようです.
- 恒星の活動は,系外惑星の信号を模倣またはマスクする重要な要因であり,潜在的な誤解につながる可能性があります.
- 恒星活動の正確な補正は,特に活発なM矮星周辺の,信頼性の高い系外惑星の検出と特徴づけに不可欠です.
関連する概念動画
01:10Kepler's First Law of Planetary Motion
4.8K
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,...
4.8K
01:29Kepler'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
01:18Kepler'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
01:10Detection of Black Holes
1.7K
Although black holes were theoretically postulated in the 1920s, they remained outside the domain of observational astronomy until the 1970s.
Their closest cousins are neutron stars, which are composed almost entirely of neutrons packed against each other, making them extremely dense. A neutron star has the same mass as the Sun but its diameter is only a few kilometers. Therefore, the escape velocity from their surface is close to the speed of light.
Not until the 1960s, when the first neutron...
Their closest cousins are neutron stars, which are composed almost entirely of neutrons packed against each other, making them extremely dense. A neutron star has the same mass as the Sun but its diameter is only a few kilometers. Therefore, the escape velocity from their surface is close to the speed of light.
Not until the 1960s, when the first neutron...
1.7K
01:24Acceleration due to Gravity on Other Planets
3.4K
The gravitational acceleration of an object near the Earth's surface is called the acceleration due to gravity. It can be measured by conducting simple experiments on Earth. However, such an experiment is impossible to conduct on the surface of other planets.
Astronomical observations are thus used to measure the acceleration due to gravity on other planets. This can be determined by observing the effect of a planet's gravity on objects close to it. The crucial factor that helps in this...
Astronomical observations are thus used to measure the acceleration due to gravity on other planets. This can be determined by observing the effect of a planet's gravity on objects close to it. The crucial factor that helps in this...
3.4K
01:21Schwarzschild Radius and Event Horizon
2.2K
No object with a finite mass can travel faster than the speed of light in a vacuum. This fact has an interesting consequence in the domain of extremely high gravitational fields.
The minimum speed required to launch a projectile from the surface of an object to which it is gravitationally bound so that it eventually escapes the object’s gravitational field is called the escape velocity. The escape velocity is independent of the mass of the object. Merging the idea of escape...
The minimum speed required to launch a projectile from the surface of an object to which it is gravitationally bound so that it eventually escapes the object’s gravitational field is called the escape velocity. The escape velocity is independent of the mass of the object. Merging the idea of escape...
2.2K