On 13 Mar 2007 01:24:19 -0700, "George Dishman"
wrote:

On 12 Mar, 22:11, HW@....(Henri Wilson) wrote:
On 12 Mar 2007 05:11:04 -0700, "George Dishman" wrote:

Right, it is just a step along the way. As you say
later there should be a statistical spread and if
you predicted every pulsar orbit had to be within
a few mas of face-on, it would indicate a problem.

The problem remains to establish a figure for the true orbital velocity given
that all we have available is the willusion.

Sure, I'm working towards explaining some of the
methods you can use to do that.

As far as I can see, the velocity curve calculated 'classically' from observed
doppler shifts should be exactly the same as my brightness curve,
The phase difference between the blue and green curves appears to remain the
same 90deg for distances of 0.2LYs and 200LYs.

However, I was
going to point out that a face-on conflicts with
the observation of a Shapiro delay so we can
discard that idea.

But the phase of the supposed Shapiro delay is based on standard Doppler.

No, the Shapiro delay must peak at the time of
superior conjunction when the line of sight
passes closest to the dwarf.

....but even Shapiro delay has a different meaning in the BaTh....although the
phase of maximum effect should still coincide with the dwarf being furthest
away. The 'delay' should be negative when the dwarf is closest.

Sort of, you are right that the 'delay' should be
negative but the effect should still be most
significant when it is farthest. As a deviation
from the normal Keplerian effects we usually discuss
GR gives this change of arrival time as a function of
phase:

Advance
|______ ______|
| \/ |
Delay

while ballistic theory predicts this:

Advance
|______/\______|
| |
Delay

Bear in mind we don't know the exact distance to
the pulsar to a few metres, it is only a relative
shift on top of the orbital effects and also the
proper motion of the whole system.

Laying aside the inversion, it still gives a valid
phase reference.

Well I don't even accept that the effect currently attributed to 'Shapiro
delay' IS actually just that. According to the BaTh, there will be a slowing of
light as it escapes the gravitational influence of the pair. The amount depends
somewhat on the position in the orbit where the light was emitted.
The final speed will not vary by much but the travel time to a distant observer
might be significantly affected. Maybe I should investigate this further...and
maybe include it in my program.
Again, it would help enormously if we could obtain brightness and velocity
curves for the dwarf.

I reckon what is happening in the case of this Pulsar is that the very heavy
neutron star is wobbling relatively slowly around its barycentre with the
dwarf.

Trouble is that you cannot have a "very heavy neutron
star", there is a limit to the ability of neutrons to
resist being crushed.

...theories, theories......

Its orbital speed could easily be less than 1 km/s. The pitch angle
might be around 60 degres or less.

The pitch can be found from the Shapiro delay just by
comparison with the empirical delay measured near the
Sun without worrying about any particular theory.

George, the situation is that there is an apparent anomaly in the pulse arrival
rate that appears to be explainable by the shapiro effect.
I'm not prepared to accept that this is the correct or only explanation. The
BaTh opens up other possibilies. You only have to look at the so called
'eclipsing binary' curves to realise that. I would say that most of these
'eclipse-like' curves are just a result of c+v, where the orbits are moderately
eccentric and the periastron is nearest to the observer. One can only tell the
difference if accurate spectral data is available.

Have a look yourself. Set Yaw angle at -90, eccentricity at ~0.7.
There is even evidence of the second small dip.

What would help greatly would be a brightness curve of the dwarf...or at least
something about its velocity variations.

I haven't seen one yet but since I don't accept
your "incompressible photon" idea it probably
wouldn't help. I want to see how far we can get
using _only_ the pulses where we agree the effects.

Well I don't think we can go much further.
All I can derive is the product (extinction distance x true velocity)

That is controlled
solely by the geometry of the orbit so it
provides a _reference_ against which the phase
of the Doppler can be measured. Conventionally
for a circular orbit it would be at a point of
zero shift but for ballistic theory the Doppler
will be a combination of velocity and acceleration
terms so the phase relative to the reference can
tell you the ratio of the velocity and acceleration
contributions.

I suggest we use the terms ADoppler and VDoppler to distinguish between these
two. ADoppler includes a VDoppler component.

OK, but exclude the VDoppler from the ADoppler and
call the combination the total.

OK, TDoppler.
The problem is that my original method (counting pulses that arrive in a
certain time interval) should take both effects into account...and its curves
are identical to those produced with 'george'.

How do we arrive at a true velocity curve when all we have is the ADoppler
willusion? Because of hte VDoppler component, the velocity curve will not
normally be quite the same as my 'brightness' curve. It will be out of phase
and have a different shape until it stabilizes with distance.

That's the key, the phase depends on the ratio so
given the Shapiro marker we should be able to find
a maximum value for the extinction distance.

As far as I can see, there is no change in phase with distance for circular
orbits. It remains at 90.
There appears to be a small change in the case of highly eliptical orbits.


If we use a computer simulation we cannot assume the hipparcos distance is
applicable unless we also assume zero extinction....and that is not something I
would like to do at this stage.

No, what we do is use a combination, if you set the
program distance to the Hipparcos level, you are
assuming no extinction and the result will usually
be multiple images which is ruled out. If you then
set it much less, you are assuming an observe at
infinity and the distance is the extinction. Having
done both, as long as the ratio is large (i.e. the
observer is at a much greater distance than the
extinction) then you can use the latter method. If
it turns out the distances are similar, then you
have to work out the exponential to get a more
accurate figure for extinction using the known
Hipparcos range.

Yes. Generally, the distance I select will be the 'extinction distance'.

...you seem to be having trouble riding your mind of everything you have been
taught in the past George.

You seem to have trouble realising that phase
tells you lots about the situation :-)

No, I can see that the V component will shift the red curve away from the
'brightness curve'...but we need the extinction distance before we can go much
further.

For a circular orbit, when the phase is 45 degrees
relative to the Shapiro peak, the ADoppler component
is equal to the VDoppler which tells you the extinction.
It will be more complex for an elliptical orbit but
that's where you program comes in.

I think the V component is always going to be much smaller than the A.
I can only detect very small phase changes even for highly eccentric orbits.

I have upgraded my program again so that you can see any number of orbits and
can increase the y scale by any factor.

If you click anywhere on the screen showing the curves a vertical line comes up
so you can compare phases.
Note, the brightness curve increases upwards, the velocity curve increases down
the screen.

Have you seen this?http://mb-soft.com/public2/cepheid.html

Crank crap I'm afraid. He makes the point that the
infalling acceleration is only 0.16 m/s^2 while the
surface gravity is 0.93 m/s^2 and suggests that's a
problem. Of course all it means is that the upward
pressure has dropped from slightly more than 0.93
when the star was expanding to about 0.77 m/s^2 or
5/6ths of the gravity when it is collapsing.

I had a look at some of his other stuff and it is
pretty clueless.

I agree. But Jerry made a big issue of it.

... The interesting question that
we will get to soon is what extinction distance
changes the phase to 45 degrees. You might have
to think a bit to see what that will tell us ;-)

Yes I can see the point. ..ADoppler starts to dominate.

Not only that, the two are equal at that point
so you know the extinction. Below that or in
particular for smaller phase angles, the phase
becomes close to proportional so if you calculate
the extinction at say 10 degrees then that at 1
degree will be about 1/10th the distance. It lets
you work out the maximum value based on the
uncertainty in the phase shift of the conventional
analysis.

There is something wrong here.
For circular orbits, I get the same phase relationship for 0.1 LYs and
100LYs....exactly 90 deg.

I think we have to incorporate the rate of change of 'bunching' rather than
just 'time between pulses'.

George


"When a true genius appears in the world, you may know
him by this sign, that the dunces are all in confederacy against him."
--Jonathan Swift.