[Message Prev][Message Next][Thread Prev][Thread Next][Message Index][Thread Index]

[vsnet-chat 38] Re: SU UMa's and TOADs

From showell@mothra.uwyo.edu Fri Feb  7 07:55 JST 1997
Received: from mothra.uwyo.edu (mothra.uwyo.edu [129.72.210.178]) by ceres.kusastro.kyoto-u.ac.jp (8.8.4+2.7Wbeta4/3.5Wpl297010918) with SMTP id HAA11597 for <tkato@kusastro.kyoto-u.ac.jp>; Fri, 7 Feb 1997 07:55:14 +0900 (JST)
Received: (from showell@localhost) by mothra.uwyo.edu (8.6.12/8.6.12) id PAA18352 for tkato@kusastro.kyoto-u.ac.jp; Thu, 6 Feb 1997 15:54:55 -0700
Date: Thu, 6 Feb 1997 15:54:55 -0700
From: Steve Howell <showell@mothra.uwyo.edu>
Message-ID: <vsnet-chat38@hoge.baba.hajime.jp>
To: tkato@kusastro.kyoto-u.ac.jp
Subject: Re:  [vsnet-chat 33] SU UMa's and TOADs
Content-Type: text
Content-Length: 1513

TOAD is not just another name for WZ Sge stars. These in fact. were fisrt
defined by their dounle-peaked spectra (due to WZ Sge being at high i).
TOADs have a number of defining properties.
Thes eare outlined in the paper in ApJ paper in 1995 vol. 439. 337.
Some are observational properties and some are guesses as to how the disk physics must work in order that current modeling sort of fits them.

observationally they are best described by large amplitudes, (6 or greater mags),
long interoutburst intervals, short orbital periods (but not THE shortest, just below the gap), essentially no normal outbursts, outbursts are not apparently
started by a normal outbusrt, light curves in optical show a "glitch"
which is likely to be the accretion disk expansion "hitting" the tidal radius,
sometimes (all? few?) the outbursts show predictable post-outburst brightenings,
and they have superhumps, but only AFTER the glitch.
The disks are possibly advected, and current disk models are NOW really
correct to use in many cases as the m-dots in TOADs are lower them 
then general alpha-disk models.

there are additional properties as well, most are likely or predicted or
based on theory.
Steve

 Dr. Steve B. Howell 
 Deptartment of Physics and Astronomy 
 University of Wyoming 
 P. O. Box 3905, University Station 
 Laramie, WY 82071  USA 
 
 Phone (307) 766-6150 
 Fax (307) 766-2652 
 e-mail: showell@kaya.uwyo.edu
 Homepage: http://wapiti.uwyo.edu/people/showell/ 
 ITW Homepage: http://wapiti.uwyo.edu/toad/

VSNET Home Page

Return to Daisaku Nogami

vsnet-adm@kusastro.kyoto-u.ac.jp