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[vsnet-j 37] V446 Her Campaign

このメイルは vsnet-j, vsolj-sci, binj の各メイリングリストに
出しています。

先日 B.T. Gaensicke さんが PI となって実施する、 V446 Her の
観測キャンペインへの参加を VSNET 上で呼び掛けました(vsnet-campaign
325, vsnet-alert 5074)。また先ほどもう一度呼び掛けを出しました
(vsnet-campaign 368)。実のところなかなか観測結果の集まりが悪く、
このままではこの研究は全く進まないことになってしまいます。皆様の
このキャンペインへの参加をお願い致します。

具体的には、他の星の観測を行う夜についでで構いませんので、一晩に
１点で構いませんのから(出来れば時間をあけて２〜３点) V446 Her の
観測を行って、v446her@uni-sw.gwdg.de (または
vsnet-campaign-data@kusastro.kyoto-u.ac.jp)に報告して頂ければ
結構です。世界的に観測を呼び掛けていて、一晩１０点程度集まり
アウトバーストパターンを明らかにしようというものです。V446 Her
は昔の新星ですが、現在は矮新星的な(降着円盤による)増光を繰り返
しています。但しそのアウトバーストパターンは普通の矮新星とは
やや異なるようです。それが新星爆発によってまだ温度の高い状態に
ある白色矮星の影響ではないかと睨んで、それを確めてみようという
ものです。

15.2-18.8 等くらいとやや暗いのですが、CCD を所有の観測者の方
には届かない暗さではないと思います。是非チャレンジしてください。
17.0 等より暗かった、というようないわゆる negative observation
でも十分に役に立ちます。以下に付ける Gaensicke の文章にもあり
ますが、V446 Her から数秒のところに２つ(正確にはかなり暗いものが
もう一つ)あります。大抵の機材では分離できないと思いますが、全部を
一つの aperture に入れた測光値で結構です。観測を行ってくださった
方は、出版される論文の共著者ということになります。

詳しい内容は以下の文章、及び
    http://vsnet.uni-sw.gwdg.de/~boris/outgoing/V446Her/
をご参照ください。ではよろしくお願い致します。

 Date: Fri, 7 Jul 2000 20:08:06 +0900 (JST)
 From: Taichi Kato <tkato>
 Subject: [vsnet-campaign 325] (fwd) V446 Her observing campaign

     We have received the following call for observations.  Please use
vsnet-campaign for communication between VSNET collaborators.
(V446 Her is an old nova, but the purpose is more or less related to
usual dwarf nova studies).

Date: Fri, 7 Jul 2000 12:13:37 +0200 (MET DST)
From: "Boris T. Gaensicke" <boris@uni-sw.gwdg.de>
Subject: V446 Her

------------------------------------------------------------------------
Dear colleagues, 

we plan for this summer an intensive campaign on the post nova V446
Her (V~18). Our interest in this object arouse as it is one of the few
post novae that shows also regular dwarf nova outbursts. In contrast
to e.g. GK Per, V446 Her has a rather typical orbital period of 4.97h
(Thorstensen & Taylor, 2000, MNRAS 312, 629). 

While the work of Honeycutt et al. (1998, ApJ 495, 933) reveals an
outburst period of ~23d with an amplitude of ~1.5mag, their RoboScope
observations could not cover in detail the rise and the decline of the
outbursts.

Our aim is to obtain a *good* contiguous light curve of V446 Her that
covers 2-3 outbursts of the system, in order to compare its outburst
characteristics to those of ``normal'' dwarf novae. We invite those of
you equipped with a CCD camera to obtain a couple of images of V446
Her per night throughout the next three months, say, until the end of
September.  To get a complete coverage (~5-10 measurements per day), it
is crucial that we find collaborators in several continents. The
resulting light curve will be published in a refereed journal,
including all contributors as co-authors.

We hope that you will join us in the study of this extremely
interesting object. If you decide to do so, please find some
technical notes below.

Thank you very much for your attention.

Boris Gaensicke, Matthias Schreiber, Daisaku Nogami
Universitaets-Sternwarte Goettingen
Germany


Technical notes: 

1) For your convenience, we have set up a Web directory 

    http://vsnet.uni-sw.gwdg.de/~boris/outgoing/V446Her/

containing a finder chart (V446Her_5x5.gif, V446Her_5x5.ps, 5'x5').
You also find a photometric sequence of comparison stars in the field
(from Henden & Honeycutt, 1997, PASP 109, 441; see the file
V446Her_sequence).  The chart of the comparison stars is available as 
V446Her_comp.gif or V446Her_comp.ps.

2) V446 Her has two nearby (~3.5") visual companions with somewhat
fainter magnitudes (Honeycutt et al. 1998; see the files
V446Her_zoom.gif and V446Her_zoom.ps).  Depending on the seeing
conditions, these three stars may not be resolved. In order to have
homogenous measurements, please compute the magnitude of *all three
stars together*, we will then correct for the contribution of the two
field stars later.

3) please send us (v446her@uni-sw.gwdg.de) your measurements on a
regular base, so that we can monitor the progress of the project. In
addition, it would be very helpful if you could send us the original CCD
frames, so that we can archive all the observations in a single
location (and, if desired, make them available to the contributors of
the campaign).

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