Mass of Pulsars vs Neutron Stars?

Do pulsars have a (slightly) larger mass than neutron stars? And / or,
do Pulsars have masses at the top of what is theoretically allowed for
neutron stars?

ie, does anyone know whether a paper has assembled masses for various
pulsars, and, for various neutron stars, where masses can be accurately
determined?

Ross

[Moderator's note: Pulsars ARE neutron stars, so perhaps the question
should be whether pulsars have slightly larger masses than OTHER neutron
stars. There is, of course, literature on this subject. Google returns
about 446,000 results for "pulsar masses", including links to an arXiv
paper, various posters, and so on on the first page. I'm no expert in
this field, but presumably mass determinations of non-pulsar neutron
stars are much more difficult. It might help to say why you suspect
that the masses of pulsars might be slightly more than those of other
neutron stars. The exact theoretical upper limit is unclear, but since
pulsar masses have a relatively broad and roughly Gaussian distribution,
most don't have masses near the upper theoretical limit. (The lower
limit is the Chandrasekhar limit, which is known more precisely. -P.H.]

On Thursday, October 20, 2016 at 7:16:29 AM UTC-4, wrot=
e:
Do pulsars have a (slightly) larger mass than neutron stars? And / or,
do Pulsars have masses at the top of what is theoretically allowed for
neutron stars?=20

An excellent recent summary of neutron star masses (including pulsars) is
here.
https://stellarcollapse.org/nsmasses
The citation to Lattimer is given on that page.

A pulsar is a neutron star in a phase of its life that is emitting
pulsed emission. The mass is really a product of how it was formed
(presumably in a supernova explosion), and its post formation
evolutionary history. Neutron stars in close binaries will probably
evolve to mass transfer, which will increase the mass of the neutron
star, and spin it up. So yes, evolution-wise, there should be a
correlation between pulsars and mass. A good search term is "pulsar
death line." Here's an example.


http://www.astro.cornell.edu/academi...lsar_graph.htm

Fast pulsars should be more massive. According to the observations
cited above, the answer is yes, on average, accreting systems have more
massive neutron stars, but there appears to be a lot of variation.
There could also be significant observational selection biases.

CM

On Thursday, October 20, 2016 at 4:16:29 AM UTC-7, wrot=
e:
Do pulsars have a (slightly) larger mass than neutron stars?
Ross

[Moderator's note: Pulsars ARE neutron stars, so perhaps the question
should be whether pulsars have slightly larger masses than OTHER neutron
stars. There is, of course, literature on this subject. Google returns
about 446,000 results for "pulsar masses", including links to an arXiv
paper, various posters, and so on on the first page.

Thanks for the posts and direction.

Yes, I did mean to say, do pulsar neutron stars have masses that
are greater than neutron stars that are not pulsars.

I'm wondering whether there is a cut off, below which a star is a
neutron star without pulsations, and above which a neutron star is
a pulsar. I have done some searching and read a bunch of papers,
but so far haven't found where anyone has compiled this distinction.
There are of course uncertainties in the measurements so will no
doubt be an overlap.

So, finding a list with small uncertainties would be nice, or, a
complete list in a data base that could be sorted would be great.

Thanks,


rt

In article ,
writes:

I'm wondering whether there is a cut off, below which a star is a
neutron star without pulsations, and above which a neutron star is
a pulsar.

Very probably not. Why should there be? As I mentioned in another
reply, a hypothesis also needs a plausible mechanism. Also keep in mind
that measuring the mass is more difficult if the object is not a pulsar.
Also, it could be a pulsar but we are not in the beam so don't see the
pulses.

On Friday, October 21, 2016 at 2:08:55 PM UTC-4, wrote:
I'm wondering whether there is a cut off, below which a star is a
neutron star without pulsations, and above which a neutron star is
a pulsar. I have done some searching and read a bunch of papers,
but so far haven't found where anyone has compiled this distinction.
There are of course uncertainties in the measurements so will no
doubt be an overlap.

There probably is a correlation. Again, see the "pulsar death line."
Radio pulsations are related to spin rate and probably accretion
history. There are some theories that accreted material can "bury" a
neutron star's magnetic field, and thereby quench pulsations. Which
would mean higher mass neutron stars could have weaker, not stronger
pulsations. Also, you need to be clear whether you mean radio, optical
or X-ray pulsations. The emission mechanisms are different and there
are X-ray pulsars that are not radio pulsars.