活性小惑星 (101955) Bennuの表面からの粒子放出エピソード
D S Lauretta1, C W Hergenrother1, S R Chesley2
1Lunar and Planetary Laboratory, University of Arizona, Tucson, AZ, USA. lauretta@orex.lpl.arizona.edu chergen@lpl.arizona.edu.
まとめ
活発な小惑星は質量損失を示しています. OSIRIS-REx宇宙船によって観測された小惑星ベヌからの粒子放出は,それが活発な小惑星であることを確認し,放出機構の洞察を示しています.
科学分野:
- 地近天体に関する研究
- 小惑星と彗星の科学
- 惑星地質学
背景:
- 活発な小惑星は,継続的な質量損失を示す天体です.
- 小惑星 (101955) Bennuは,重要な科学的関心のあるサンプル返還ターゲットです.
- 小惑星の進化と危険性評価には 質量喪失メカニズムを理解することが重要です
研究 の 目的:
- 小惑星 (101955) Bennuからの粒子放出の証拠を提示する.
- 観測された射出事件と関連する粒子を特徴づける.
- 活性小惑星現象を誘発する 潜在的メカニズムを調査する
主な方法:
- OSIRIS-REx宇宙船からの画像を使用して,粒子放出イベントを検出および分析しました.
- 大事な事象の粒子速度,サイズ,エネルギーの推定値
- 引力的に結合されたエジェクトの軌跡と光学特性を決定した.
- 射出イベントの複数の物理的仮説を評価した.
主要な成果:
- (101955) ベヌは,重複した粒子の射出によって,活性小惑星であることが確認された.
- 源領域とエネルギーを含む最大の噴出イベントの定量化キーパラメータ.
- ベヌの重力によって一時的に軌道に乗った粒子を観測した.
- 粒子放出の 可能性のあるメカニズムを 特定した
結論:
- ベヌの活動は 活発な小惑星現象の ユニークなケーススタディを提供します
- 観測された噴出は,小さな天体の表面プロセスに洞察を与えます.
- 主要なエジェクションメカニズムを決定するためにさらなる研究が必要である.
関連する概念動画
Impact: Problem Solving
420
In an experiment conducted during a Mars mission, a rover propels a projectile with an initial velocity, and the projectile rebounds after colliding with the Martian surface. To ascertain the maximum height attained by the projectile after this collision, the known restitution coefficient and acceleration due to gravity are employed.
By designating the launch point as the origin and utilizing kinematic equations, the vertical component of the projectile's velocity at the point of impact is...
By designating the launch point as the origin and utilizing kinematic equations, the vertical component of the projectile's velocity at the point of impact is...
420
Impulse
21.2K
According to Newton’s second law of motion, the rate of change of the momentum of an object is the net external force acting on it. The total change in momentum between two timepoints thus depends on both the external force acting on it and the time over which it acts. Describing this mathematically, the total change of an object’s motion is proportional to the force vector and the time over which it is applied. This product is called impulse.
Additionally, it can be shown that the...
Additionally, it can be shown that the...
21.2K
Projectile Motion: Example
12.4K
The theory of projectile motion is very useful for players of several sports to improve their performance. For example, a javelin thrower needs to throw their javelin in such a way that it travels as far as possible. The javelin thrower takes a short run-up to increase the initial speed of the javelin. The range of a projectile is at its maximum at a 45° angle so javelin throwers try to angle their throw as close to 45° as possible.
When we speak of the range (R) of a projectile on...
When we speak of the range (R) of a projectile on...
12.4K
Projectile Motion
30.7K
An object thrown in the air follows a parabolic path under the influence of Earth's gravitational force. The motion of such an object is called projectile motion, and the object itself a projectile. The parabolic path followed by the projectile is called the trajectory. Some common examples of projectile motion are the launching of fireworks, a golf ball in the air, meteors entering the Earth's atmosphere, and the firing of bullets.
When an object falls under gravity and has no...
When an object falls under gravity and has no...
30.7K
Rocket Propulsion In Empty Space - II
3.3K
The motion of a rocket is governed by the conservation of momentum principle. A rocket's momentum changes by the same amount (with the opposite sign) as the ejected gases. As time goes by, the rocket's mass (which includes the mass of the remaining fuel) continuously decreases, and its velocity increases. Therefore, the principle of conservation of momentum is used to explain the dynamics of a rocket's motion. The ideal rocket equation gives the change in velocity that a rocket...
3.3K
Types of Collisions - II
9.5K
When two or more objects collide with each other, they can stick together to form one single composite object (after collision). The total mass of the object after the collision is the sum of the masses of the original objects, and it moves with a velocity dictated by the conservation of momentum. Although the system's total momentum remains constant, the kinetic energy decreases, and thus such a collision is an inelastic collision. Most of the collisions between objects in daily life are...
9.5K


