関連する実験動画
Updated: Jun 23, 2026

16:20
Hyperpolarized Xenon for NMR and MRI Applications
Published on: September 6, 2012
ラジオパルサー/X線バイナリリンク
Anne M Archibald1, Ingrid H Stairs, Scott M Ransom
1Department of Physics, McGill University, 3600 Rue University, Montréal, Quebec, H3A 2T8, Canada. aarchiba@physics.mcgill.ca
まとめ
研究者らは,バイナリ系にある近くの無線ミリ秒パルサー (MSP) を検出した. この発見は,パルサーが最近,低質量X線バイナリ (LMXB) 段階から移行したことを示唆しており,現在の蓄積円盤の欠如によって示されています.
科学分野:
- 天文学と天体物理学について
- コンパクトなオブジェクト コンパクトなオブジェクト
- バイナリーシステム バイナリーシステム
背景:
- ミリ秒パルサー (MSP) は急速に回転する中性子星で,同伴星からの質量移転によって回転したと考えられています.
- 低質量X線バイナリー (LMXB) システムは,MSPの理論上の祖先であるが,直接的な観測のリンクは依然として難解である.
- LMXBにおけるラジオパルスに関する以前の探求は,決定的な検出が得られませんでした.
研究 の 目的:
- 新しい無線ミリ秒パルサー (MSP) の検出を報告する.
- 近隣のMSPシステムの進化的状態を,光学的に同定された伴侶で調査する.
- 低質量X線バイナリー (LMXB) 段階からアクティブラジオパルサー段階への移行を調査する.
主な方法:
- ミリ秒パルサーからの無線パルサーションの検出.
- フォローアップの観測は,光学光度測定とスペクトロスコピーを含む.
- 蓄積円盤の有無を特定するための光学データの分析.
主要な成果:
- 近くの無線ミリ秒パルサー (MSP) が発見され,観測されました.
- このシステムは,光学的に同定された伴星と円形のバイナリー軌道を示しています.
- 光学観測は,最近,蓄積円盤が消え去ったことを示しており,質量移転の停止を示唆している.
結論:
- 検出された無線MSPは,低質量X線バイナリ (LMXB) 段階から移行した可能性が高い.
- 現在の蓄積円盤の欠如は,最近のLMXB段階を指している.
- この発見は,ミリ秒パルサー形成のスピンアップモデルのための観測的証拠を提供します.
関連する概念動画
Atomic Nuclei: Larmor Precession Frequency
The earth's gravitational field produces a 'twisting force' perpendicular to the angular momentum of a spinning mass (such as a spinning top) that causes the mass to 'wobble' around the gravitational field axis in a phenomenon called precession. Similarly, the magnetic moment (μ) of a spinning nucleus precesses due to an external magnetic field directed along the z-axis. The precession of the magnetic moment vector about the magnetic field is called Larmor precession, and the angular frequency...
NMR Spectrometers: Radiofrequency Pulses and Pulse Sequences
A pulse is a short burst of radio waves distributed over a range of frequencies that simultaneously excites all the nuclei in the sample. Upon passing a radio frequency pulse along the x-axis, the nuclei absorb energy corresponding to their Larmor frequencies and achieve resonance. This shifts the net magnetization vector from the z-axis toward the transverse plane. This angle of rotation of the magnetization vector, or the flip angle, is proportional to the duration and intensity of the pulse.
Detection of Black Holes
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...
Schwarzschild Radius and Event Horizon
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 velocity with the...
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 velocity with the...
Generating Electromagnetic Radiations
The German physicist Heinrich Hertz (1857–1894) was the first to generate and detect certain types of electromagnetic waves in the laboratory. Starting in 1887, he performed a series of experiments that confirmed the existence of electromagnetic waves and verified that they travel at the speed of light. Hertz used an alternating-current RLC (resistor-inductor-capacitor) circuit that resonated at a known frequency and connected it to a loop of wire. High voltages induced across the gap in the...
¹H NMR Signal Multiplicity: Splitting Patterns
When protons A and X are coupled, their nuclear spin energy levels are slightly modified. This is because the energy required to excite proton A to a spin state parallel to proton X is slightly different from the energy required for it to become anti-parallel to spin X. Consequently, there are two possible excitation frequencies for A (A1 and A2), depending on the spin state of X, and vice versa. The mutual nature of coupling implies that the difference between frequencies A1 and A2, indicated...
