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From: "Donn Starkey" <starkey73@mchsi.com>
Subject: RE: [vsnet-campaign-polar 13] Re: (fwd) Assistance Needed with Light Curve of V1432 Aql
Date: Sat, 7 Sep 2002 09:44:22 -0500
Tachi:
Thank you for your input on V1432 Aql. I just received your message this
morning after it spent 4 days percolating through the Kyoto server ;-)
Are any particular filters preferred over others for observing polars?
Thanks.
==============================================
The price of freedom is constant vigilance.
Donn Starkey
starkey73@mchsi.com
http://starkey.ws
AAVSO Observer SDB - CBA Indiana - VSNET Observing Team
==============================================
-----Original Message-----
From: owner-vsnet-campaign-polar@ooruri.kusastro.kyoto-u.ac.jp
[mailto:owner-vsnet-campaign-polar@ooruri.kusastro.kyoto-u.ac.jp]On
Behalf Of Taichi Kato
Sent: Wednesday, September 04, 2002 1:32 AM
To: vsnet-campaign-ccd-discussion@ooruri.kusastro.kyoto-u.ac.jp;
vsnet-campaign-polar@ooruri.kusastro.kyoto-u.ac.jp;
vsnet-chat@ooruri.kusastro.kyoto-u.ac.jp
Subject: [vsnet-campaign-polar 13] Re: (fwd) Assistance Needed with
Light Curve of V1432 Aql
Re: (fwd) Assistance Needed with Light Curve of V1432 Aql
V1432 Aql is an eclipsing polar (AM Her star). In contrast to other
CVs (dwarf novae, novalike stars etc.), the emission source (and the
eclipsed
body) is an accretion stream and accretion column on a white dwarf
(not an accretion disk). The temporal structure of the accretion stream
and accretion column strongly vary, and have own irregularities (blobs,
QPOs originating near the accretion shock region etc.). They may have
affected Donn's observation.
By the way, the source of emission from a polar is a combination of
synchrotron emission and thermal emission in the optical range. The
frequency dependency of the former emission is strikingly different from
usual CVs (with thermal emissions). There even exist outstanding
differences
between V-band and "white light" (unfiltered) light curves. Due to this
complexity, "white light" light curves in polars convey less information
than in other CVs. So we don't usually recommend unfiltered photometry
(as in other CVs) of polars except on rare occasions (simultaneous
observation
with an X-ray sattelite or when knowledge of one-pole or two-pole accretion
is important). Filtered photometry is more recommended in these sources,
but they are usually too faint to get sufficient S/N and time-resolution
with small telescopes. A minimum requirement would be 0.5-1.0 m telescope
with a high Q.E. CCD except on a few bright sources.
Regards,
Taichi Kato
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