中性子星 の 熱核 爆発 は,その 噴射 の 速さ を 明らか に する
Thomas D Russell1, Nathalie Degenaar2, Jakob van den Eijnden3,4
1Institute of Space Astrophysics and Cosmic Physics, INAF, Palermo, Italy. thomas.russell@inaf.it.
Nature
|March 28, 2024
まとめ
科学者は初めて ニュートロン星からのジェットの速度を測定しました これらのコンパクトジェットは ブラックホールのジェットよりも遅いので ジェットが発射される方法について 新たな洞察を与えてくれます
科学分野:
- 天体物理学
- 高エネルギー天体物理学
背景:
- 相対論的ジェットは 蓄積や大災害における 重要な現象です
- これらのジェット機の発射メカニズムは 未知のままです
- ニュートロン星のジェット速度を測定することで, 蓄積の流れや 恒星に固定された磁場を区別することができます.
研究 の 目的:
- ニュートロン星から発する 圧縮ジェットの速度を測るため
- ジェット特性に対する蓄積率の影響を調査する.
- 主要なジェット発射機構を理解するために
主な方法:
- I型X線爆発の後のジェット放射の明るいフレアを観察する.
- ジェットフレアと 増加した質量増加率の相関関係
- 観測したフレアを使って ジェット速度を測定する
主要な成果:
- I型X線爆発のすぐ後のジェット放射で 明確なフレアが観測された.
- 中性子星のコンパクトジェット速度を測定しました.
- これらのジェットは ブラックホールのジェットよりも 比較的遅いことが分かりました
結論:
- タイプIのX線爆発は一時的に 蓄積率を高め 観測可能なジェットフレアを誘発します
- 測定されたジェット速度は,ジェット打ち上げメカニズムを研究するための新しい方法を提供します.
- 中性子星のジェット速度は ブラックホールのジェットよりも遅いので 異なるパワーメカニズムを示唆しています
関連する概念動画
02:45Nuclear Fusion
19.6K
The process of converting very light nuclei into heavier nuclei is also accompanied by the conversion of mass into large amounts of energy, a process called fusion. The principal source of energy in the sun is a net fusion reaction in which four hydrogen nuclei fuse and ultimately produce one helium nucleus and two positrons.
A helium nucleus has a mass that is 0.7% less than that of four hydrogen nuclei; this lost mass is converted into energy during the fusion. This reaction produces about...
A helium nucleus has a mass that is 0.7% less than that of four hydrogen nuclei; this lost mass is converted into energy during the fusion. This reaction produces about...
19.6K
03:20Nuclear Transmutation
17.5K
Nuclear transmutation is the conversion of one nuclide into another. It can occur by the radioactive decay of a nucleus, or the reaction of a nucleus with another particle. The first manmade nucleus was produced in Ernest Rutherford’s laboratory in 1919 by a transmutation reaction, the bombardment of one type of nuclei with other nuclei or with neutrons. Rutherford bombarded nitrogen-14 atoms with high-speed α particles from a natural radioactive isotope of radium and observed...
17.5K
01:21Schwarzschild Radius and Event Horizon
2.0K
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...
2.0K
02:50Nuclear Fission
9.7K
Many heavier elements with smaller binding energies per nucleon can decompose into more stable elements that have intermediate mass numbers and larger binding energies per nucleon—that is, mass numbers and binding energies per nucleon that are closer to the “peak” of the binding energy graph near 56. Sometimes neutrons are also produced. This decomposition of a large nucleus into smaller pieces is called fission. The breaking is rather random with the formation of a large...
9.7K
03:18Nuclear Stability
18.8K
Protons and neutrons, collectively called nucleons, are packed together tightly in a nucleus. With a radius of about 10−15 meters, a nucleus is quite small compared to the radius of the entire atom, which is about 10−10 meters. Nuclei are extremely dense compared to bulk matter, averaging 1.8 × 1014 grams per cubic centimeter. If the earth’s density were equal to the average nuclear density, the earth’s radius would be only about 200 meters.
To hold positively charged protons together...
To hold positively charged protons together...
18.8K
01:23Atomic Nuclei: Nuclear Relaxation Processes
651
In the absence of an external magnetic field, nuclear spin states are degenerate and randomly oriented. When a magnetic field is applied, the spins begin to precess and orient themselves along (lower energy) or against (higher energy) the direction of the field. At equilibrium, a slight excess population of spins exists in the lower energy state. Because the direction of the magnetic field is fixed as the z-axis, the precessing magnetic moments are randomly oriented around the z-axis.
651