"Henri Wilson" HW@.... wrote in message
...
On 16 Feb 2007 00:56:32 -0800, "George Dishman"
wrote:
On 15 Feb, 22:55, HW@....(Henri Wilson) wrote:
On 15 Feb 2007 00:41:00 -0800, "George Dishman"
wrote:
....
More likely he will say the speeds unify so fast
there is no time for the bunching to cause
significant brightness variation. Again that comes
down to the value he chooses for extinction distance
as a function of density.

It's complicated George. For one thing, the effect appears to depend on
orbit
period. ...which stands to reason because obviously the light emitted by
a star
traveling towards us right now cannot unify with light that WILL BE
emitted in
say 8 months time when the star is moving away.

Of course it should, the ISM hasn't changed in
that time. The distance should be independent
of the orbital parameters but probably dependent
on the type of star which will influence the
density of the stellar wind.

'Unification' is not like conventional 'extinction' even though I often
call it
'extinction' for convenience.

Whatever name you use, as you said in another post, it
is regulated by the 'quality [of] space' that the light
is passing through. I talk of the ISM as shorthand but
more likely it is the local stellar wind that controls
it.

On the other hand, the extinction rate for short period contact binaries
is
very high. The required unification distance can be less than 1 LY.

Let's see what you get for J1909-3744.

If I know the details of the dwarf I might be able to tell you something.

Magnitude around 21, variability hasn't been measured,
temperature 8500K, mass 0.2 Msun.

George