by Ann » Tue Mar 05, 2019 3:16 pm
Locutus76 wrote: ↑Tue Mar 05, 2019 11:19 am
So what are all the other purple bubbles in the image? X-Ray emitting stars within our own galaxy?
The Crab Nebula and its pulsar. Photo: NOAO.
As you can see in the APOD, most of the purple sources are located in the disk of the galaxy NGC 3079. That is no accident, because they belong to NGC 3079. They are most likely neutron stars or pulsars, but I suppose that some of them might be accreting stellar mass or possibly intermediate mass black holes.
Take a look at the Crab Nebula at right. It is the remnant of a bright supernova that exploded in 1054 AD.
In the center of the Crab Nebula is a tiny, extremely compact object, which is the remnant of the core of the star that exploded in 1054.
Wikipedia wrote:
At the center of the nebula lies the Crab Pulsar, a neutron star 28–30 kilometres (17–19 mi) across with a spin rate of 30.2 times per second,[6] which emits pulses of radiation from gamma rays to radio waves. At X-ray and gamma ray energies above 30 keV, the Crab Nebula is generally the brightest persistent source in the sky, with measured flux extending to above 10 TeV.
The Crab pulsar is a neutron star, which is to say that it has collapsed under its own gravity to the last possible stage of compression until it has to collapse into a black hole. But the Crab Nebula pulsar is not only a neutron star, but also a pulsar, because it emits pulses that glow bright at X-ray wavelengths. The pulses also appear to flicker on and off as the pulsar itself rotates 30.2 times per second. In the picture at left, you can see how the pulsar appears to turn on and off. So what part do the actual pulses play and what part does the breakneck rotation play? Good question, and one that I can't answer!
The object to the left of the Crab pulsar is a normal star.
Several of the purple sources in NGC 3079 are likely to be pulsars or neutron stars.
Ann
[quote=Locutus76 post_id=290377 time=1551784777 user_id=144427]
So what are all the other purple bubbles in the image? X-Ray emitting stars within our own galaxy?
[/quote]
[float=right][img2]http://www.messier.seds.org/Pics/Jpg/m1psr_k.jpg[/img2][c][size=85]The Crab Nebula and its pulsar. Photo: NOAO.[/size][/c][/float]As you can see in the APOD, most of the purple sources are located in the disk of the galaxy NGC 3079. That is no accident, because they belong to NGC 3079. They are most likely neutron stars or pulsars, but I suppose that some of them might be accreting stellar mass or possibly intermediate mass black holes.
Take a look at the Crab Nebula at right. It is the remnant of a bright supernova that exploded in 1054 AD.
In the center of the Crab Nebula is a tiny, extremely compact object, which is the remnant of the core of the star that exploded in 1054.
[quote][url=https://en.wikipedia.org/wiki/Crab_Nebula]Wikipedia[/url] wrote:
At the center of the nebula lies the Crab Pulsar, a neutron star 28–30 kilometres (17–19 mi) across with a spin rate of 30.2 times per second,[6] which emits pulses of radiation from gamma rays to radio waves. At X-ray and gamma ray energies above 30 keV, the Crab Nebula is generally the brightest persistent source in the sky, with measured flux extending to above 10 TeV. [/quote]
The Crab pulsar is a neutron star, which is to say that it has collapsed under its own gravity to the last possible stage of compression until it has to collapse into a black hole. But the Crab Nebula pulsar is not only a neutron star, but also a pulsar, because it emits pulses that glow bright at X-ray wavelengths. The pulses also appear to flicker on and off as the pulsar itself rotates 30.2 times per second. In the picture at left, you can see how the pulsar appears to turn on and off. So what part do the actual pulses play and what part does the breakneck rotation play? Good question, and one that I can't answer!
The object to the left of the Crab pulsar is a normal star.
Several of the purple sources in NGC 3079 are likely to be pulsars or neutron stars.
Ann