[vsnet-alert 5381] (fwd) Re: DO Dra rare outburst

[Taichi Kato <tkato>]

>From mukai Thu Nov 16 15:28:18 2000
Subject: Re: DO Dra rare outburst
To: extpasc@rz.uni-sb.de (Patrick Schmeer)
Date: Thu, 16 Nov 2000 15:28:18 -0500 (EST)
Cc: vsnet-alert@kusastro.kyoto-u.ac.jp, vsnet-outburst@kusastro.kyoto-u.ac.jp,
	vsnet-ip@kusastro.kyoto-u.ac.jp, news@cba.phys.columbia.edu

Hello,

>
>Visual magnitude estimates by P. Schmeer, Bischmisheim, Germany:
>
>DO DRACONIS  (NLDQ)
>Nov. 15.72  UT, [12.5 ; 15.896, [13.3 ; 16.729,  11.1 ; 16.776,  11.0 
>Sequence:  AAVSO
>Instrument: 203-mm SCT  
>(partly/mostly cloudy skies)  
>
>The previous outburst of this intermediate polar occurred 1999 
>Sept. 20-24. This is the shortest interval ever observed -
>only 423 days.  
> 

This is great news.  Coel Hellier, Joe Patterson and I have recently been
awarded observing time on the RXTE satellite on intermediate polars in
outbursts, on up to 3 targets, 100,000 s of on-source time per target.
This target (which we prefer to call YY Dra, DO Dra being the second
designation for the same variable) is one of the 14 candidates we listed
in our proposal.

I have just sent in a request to the RXTE operations center to start
observing YY (DO) Dra.  I would like to ask all interested observers
--- amateurs and professionals --- to obtain as much photometric and
spectroscopic data, and contact me.

Our interests are: (1) study of changing accretion geometry near the
magnetic white dwarf, in response to the changing mass accretion rate;
(2) study of outburst mechanism, in particular to see if the mass input
rate from the secondary to the disk has increased or not, and if so,
by how much.  During the previous outburst, for which Dr. Szkody obtained
brief RXTE observations, the X-ray flux increased by a factor of ~40
but the spin pulse almost disappeared!  We hope to observe similar
changes, but with much more data, and would like to contrast the
X-ray behaviors with the optical.

			Best wishes,

				Koji Mukai
			(mukai@milkyway.gsfc.nasa.gov)

VSNET Home Page

Return to Daisaku Nogami

---

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