Questions tagged [pulsar]

Questions regarding neutron stars which emit regular pulses of electromagnetic radiation.

Filter by
Sorted by
Tagged with
28
votes
2answers
2k views

What causes a star to become a pulsar?

What processes does a star undergo to become a pulsar? Does it take a very specific star with a certain set of qualities such as "Just the right mass, diameter, and composition," or is it a freak ...
20
votes
1answer
2k views

What causes fast moving pulsars to move so fast?

This article investigates the traces left in the ISM by fast moving pulsars. Is there a mechanism specific to pulsars that causes them to move so fast, or are there just as many fast moving stars? ...
20
votes
1answer
348 views

Can we detect pulsars that aren't “pointed” towards us?

A pulsar is a highly magnetized rotating neutron star that emits beams of radiation through its magnetic poles, in the direction of the Earth. This makes it seem to pulse, as seen from Earth. There ...
19
votes
4answers
9k views

How Would a Neutron Star Actually Appear?

Having seen many pictures produced by artists of neutron stars and planets that orbit some of them, I was wondering how a pulsar would appear to a human being, in visible light (assuming the intense ...
17
votes
3answers
571 views

Does the observed period of a pulsar change with the time of year?

Over in the Physics SE a question was posted asking about the difference in the time dilation of the Earth between perihelion and aphelion: Does Earth experience any significant, measurable time ...
16
votes
3answers
2k views

What is the probability of seeing a neutron star as a pulsar?

Pulsars are neutron stars that emit a beam of electromagnetic radiation that is not aligned with its rotation axis. If the Earth passes through that beam of radiation, we see a pulsar. Pulsars are ...
16
votes
2answers
986 views

Are there neutron stars whose magnetic axis and rotating axis are the same, and if so what will happen?

I know that there's probably a higher chance of having a neutron star that has its magnetic axis inclined to the rotational axis rather than having it perfectly aligned. If they are not aligned, the ...
15
votes
2answers
6k views

What causes a neutron star to become a pulsar?

Leading on from this pulsar question, what criteria/processes make neutron stars become pulsars, do all neutron stars become pulsars?
13
votes
1answer
1k views

Pulses from a pulsar

What is/was the motivation behind attributing the pulses received from a pulsar to the rotation of an object (neutron star) and emission from the magnetic poles (of the said neutron star), given that ...
13
votes
1answer
441 views

What is the significance of the discovery of a pulsar flipping between radio and x-ray emissions?

This morning on the radio I heard about the discovery of a pulsar that, due to its proximity to a companion star, was flipping between a state where it emitted radio waves and one where it emitted x-...
11
votes
1answer
250 views

Crab Nebula Time Period

I've learned that the time period for a rotating neutron star, i.e., a pulsar is very accurate and can be used as an interstellar clock. But according to Walter Lewin's 8.01 Lec 19 on classical ...
9
votes
1answer
260 views

How can I hear (or at least detect) a pulsar at home?

Scott Manley's video Using Relativistic Raytracing &X-Rays To See Detail on Surface Of Neutron Star talks about X-ray measurements using the NICER X-ray telescope attached to the International ...
7
votes
2answers
432 views

Why are the magnetic poles of a pulsar so far off the rotational axis, yet stable?

My understanding is that a pulsar is a neutron star whose magnetic poles don't coincide with the rotational poles and whose magnetic poles sweep through Earth (allowing us to hear radio noise). If we ...
6
votes
1answer
239 views
6
votes
2answers
320 views

How did Jocelyn Bell Burnell discover the periodicity of CP 1919?

According to Wikipedia, in 1967, a radio signal was detected using the Interplanetary Scintillation Array of the Mullard Radio Astronomy Observatory in Cambridge, UK, by Jocelyn Bell Burnell. The ...
6
votes
1answer
71 views

Do the neutrons in neutron stars emit the radio waves?

Neutrons can, especially in extreme circumstances (and large concentrations) emit electromagnetic radiation. I specifically asked about this in Physics S.E. Has a free neutron ever been shown to ...
6
votes
2answers
112 views

Do pulsar beams interact with the interstellar medium?

Pulsars are rotating objects that emit a beam in a direction that is not aligned with the axis of rotation. Because of this, we see them as a periodic pulse. If the beam isn't towards us, we don't see ...
6
votes
1answer
197 views

Brightest Radio Source In the Universe

I would have assumed that the brightest radio source in the Universe is a quasar of some kind (perhaps 3C 273) given that the average pulsar has luminosity of $~10^{40} \text{Watts}$ and this is the ...
6
votes
1answer
292 views

How to tell a pulsar is rotation-powered or accretion-powered?

We need to calculate P/Pdot? A pulsar may switch between theses two states. For a rotation powered pulsar, it can pulse and, the pulsed Lx can be much larger than the luminosity given by its ...
6
votes
1answer
125 views

What are realistic and unrealistic values for the high energy gamma ray spectral indices of pulsar wind nebulae?

This summer, I was working on a project fitting very high energy gamma ray spectra of the Crab Nebula, a pulsar wind nebula. At energies about $\sim$1 TeV, a simple power law suffices, i.e. $\phi(E)\...
5
votes
3answers
202 views

How do we know pulsars have two beams?

Pulsars are neutron stars the emit a beam of electromagnetic radiation that is not aligned with their rotation axis. So we can only see a neutron star as a pulsar if the beam crosses Earth's path. ...
5
votes
1answer
585 views

Does Doppler shift affect apparent pulsar frequency?

We know that redshift and blueshift is the result of the frequency of light waves reflected or emitted by an object lengthening or shortening due to the relative velocity of the observer moving away ...
5
votes
1answer
70 views

What is a typical polar angle of a pulsar beam?

I've found many articles on the geometry of pulsar beams, but I have not been able to find what would be a typical angle for the beam cone. Illustrations I've found seem to look like it might be 1 or ...
5
votes
1answer
289 views

How bright is the Crab Pulsar's 30 Hz modulation in visible light? What color is it?

This answer to Has great eyesight been necessary for astronomers? mentions Astronomer Jocelyn Bell Burnell's recounting of a likely first visual observation of a pulsar. This can be found for example ...
5
votes
3answers
154 views

Can't pulsars and stars be used for gravitational wave measurement?

Suppose that we collected photons from a distant star, and they arrive regularly at 15 photons every microsecond onto a CCD, when a gravity wave bends space time, wouldn't the regular 15 photons graph ...
5
votes
1answer
113 views

Is the pulsar map on the Pioneer/Voyager probes only meaningful for earthlings?

The Pioneer probes brought plaques (and later the Voyagers two golden discs) with a "pulsar map" imprinted on them. The purpose of the map is to make the position of the Sun clear for an ...
5
votes
2answers
146 views

Can a pulsar hit us with both beams?

Can a pulsar have an axial tilt close enough to $90^\circ$ to hit us with both beams for two pulses per rotation?
5
votes
2answers
237 views

Rule of Exception in All Nearest Objects

I once heard of a strange phenomenon, but now cannot find anything about it on the Internet. I might be looking for the wrong keywords or misremember some relevant aspect. So maybe someone here can ...
5
votes
4answers
2k views

Hulse Taylor Binary Pulsar - How is “Cumulative Periastron Time shift” calculated?

Following on from a previous question about the interesting Hulse Taylor Binary Pulsar. BACKGROUD Weisberg & Taylor, 2004 present a graph showing the change in "Cumulative Periastron Time Shift" ...
5
votes
1answer
181 views

Is there a significant population of neutron stars outside the galactic plane?

Pulsar kicks originating from supernovae can impart neutron stars with speeds of 100-500 km/s, often at or close to the escape velocity of the Milky Way. Even if a pulsar fails to escape the galaxy, ...
5
votes
1answer
347 views

which pulsar has the longest spin period so far?

Vela X-1 has a 283s spin period, while this one may have a 2.7hr spin period. However neither of them is included in ATNF catalog. They are not included in $p-\dot{p}$ diagram either. The longest ...
5
votes
1answer
186 views

How did the Hulse-Taylor Pulsar Provide Confirming Evidence of General Relativity?

What measurements and observations of the Hulse-Taylor Pulsar agreed precisely with the predictions of general relativity, and how did these measurements support the theory?
5
votes
0answers
39 views

How is angular momentum transferred between a neutron star and its accretion disk?

Accreting neutron stars can either gain or loose angular momentum via interaction with their accretion disks. This leads to either spin-up or spin-down. Which of the two is the case, depends on the ...
4
votes
2answers
495 views

Is there a Vela Nebula?

The Vela pulsar is a neutron star from a supernova that exploded 10,000 years ago. It spins 11 times a second. The Crab Nebula along with the central Crab Pulsar formed 1000 years ago. This pulsar ...
4
votes
2answers
348 views

How do I make a custom pulsar map?

I'm looking to make a custom pulsar map like the one on the Voyager Records, but for an arbitrary location within the Milky Way Galaxy. I'm not even sure where to begin.
4
votes
1answer
177 views

Why do pulsars turn “off” from rotation?

I was looking at a wikipedia article (https://en.wikipedia.org/wiki/Pulsar#Formation,_mechanism,_turn_off) and I came across an interesting aspect that said pulsars turn off from rotation. What I don'...
4
votes
1answer
227 views

Hulse-Taylor binary pulsar - what is the rate of mass/energy loss from the source?

Following on from an earlier question about the very interesting Hulse-Taylor binary pulsar. The high-frequency (radio) beam from the spinning pulsar sweeps across Earth about 17 times per second. ...
3
votes
2answers
650 views

Pulsars: How do astronomers measure minute changes in period (~picoseconds per year)?

I've been to some talks that mention how stable the period of a millisecond pulsar is over long periods of time. Recently, it was mentioned that astronomers have calculated the change in period over ...
3
votes
1answer
93 views

How are pulsars detected from Earth?

This paper on Arxiv indicates that the signal period of known pulsars is 1 ms-15 s (0.07-1,000 Hz since F=1/T). I have an EE background and it's a long story how I ended up here, but suffice it to say ...
3
votes
2answers
123 views

Pulsars with accreting disk in binary system

Following this line, I am wondering about the following question. Accreting pulsars in binary systems are usually thought to accrete from a prograde disk, so increasing their spin in the process. ...
3
votes
1answer
47 views

How is the polar angle of a pulsar beam determined?

I just read the question "What is a typical polar angle of a pulsar beam?" and I was surprised that it had an answer. I thought there was little real information besides the timing of the ...
3
votes
1answer
85 views

Have any more “white dwarf pulsars” been discovered or searched for?

Back in 2016, Marsh et al. reported that the binary system AR Scorpii exhibits complex radio signals similar to those observed from traditional pulsars. In particular, pulsed synchrotron emission ...
3
votes
1answer
89 views

Could a closely orbiting pulsar be used to study a black hole?

If we were to locate a pulsar in a close elliptical orbit around a black hole, could this reveal significant information about the black hole (e.g. time dilation / structure)? Could this even tell us ...
3
votes
2answers
312 views

How to find period of a pulsar from a given time sampled voltage data?

I've a data file with 2 columns, each containing time sampled voltage output (a sequence of real numbers) from a radio telescope, so there is a pair of telescope which are measuring the signal here. ...
3
votes
1answer
41 views

How to determine arrival time delay given dispersion measure?

In an online textbook, the following formula is given to calculate the arrival time delay between two frequencies, $v_1, v_2$ in a dispersed radio pulse: $$t_1 - t_2 = 4.15 \cdot DM [(v_1/\text{GHz})^{...
3
votes
1answer
1k views

Could human life thrive on a planet in a pulsar star system?

Aleksander Wolszczan of Pennsylvania State University found three planets circling a pulsar called PSR B1257+12.Two of the planets were the size of Earth.The pulsar observed by Spitzer, named 4U 0142+...
3
votes
0answers
26 views

What is the “radiation sound speed” inside an accretion column?

I was trying to read "A New Two-fluid Radiation-hydrodynamical Model for X-Ray Pulsar Accretion Columns" and its follow-up paper both by West et al. and came across a quantity called "radiation sound ...
2
votes
2answers
96 views

Can a pulsar also be a magnetar?

I know this is a simplistic question, but I cannot find a straight answer... Also, is it possible most or all neutron stars are magnetars and/or pulsars? It's just hard to see all of their properties ...
2
votes
1answer
136 views

How do I download PSRCHIVE and Tempo2 for pulsar timing on Mac Mojave?

I am fairly new to pulsar astronomy, and I need to download PSRCHIVE and then Tempo2. I have followed the instructions online here: PulsarAstronomy.net I'm also pretty new to linux commands/Mac ...
2
votes
1answer
163 views

Birth and Evolution of Millisecond Pulsars

How are millisecond pulsars formed, and what is the evolutionary track of a millisecond pulsar?