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From: starrfie@hydro.la.asu.edu (Sumner Starrfield)
Subject: [active_stars bright cv] UPDATE to AD Leo and SS Cyg Simultaneous Observations w (fwd)
Date: Sun, 23 May 93 15:05:57 MST
To: nova@nova.la.asu.edu
Forwarded message:
>From robinson@astro.psu.edu Sat May 22 15:00:30 1993
Date: Sat, 22 May 93 17:49:13 EDT
Message-ID: <vsnet-history1022@hoge.baba.hajime.jp>
To: mwex@astro.astro.psu.edu
Subject: [active_stars bright cv] UPDATE to AD Leo and SS Cyg Simultaneous Observations w
From: "Craig Robinson" <robinson@astro.psu.edu>
Reply-To: "Craig Robinson" <robinson@astro.psu.edu>
Sender: robinson@astro.psu.edu
[Posted to: the MultiWaveLink targets of opportunity mailing list]
The following is an update to the previous request for AD Leo and
SS Cyg simultaneous observations with the ASCA satellite. The AD Leo
observations are scheduled starting at 01:25 UT on May 24th and
the SS Cyg observations will start at 20:58 UT on May 26th. Both
observations are expected to last for over 21 hours.
Thirteen observatories (plus the observers of the AAVSO) on four
continents will take part in the simultaneous observations. Additional
observers would still be welcome. Please note that SS Cyg is in the
process of brightening thereby allowing for observations by users of
telescopes with quite small apertures. (A message from Dr. Janet Mattei
of the AAVSO is appended below providing recent observations of
SS Cyg by AAVSO members). In particular, high precision photometry of SS Cyg
during the ASCA observations would be quite useful in searching for optical
oscillations.
The simultaneous observations of the M dwarf flare star
AD Leo (SAO 81292, V=9.4 mag) by ASCA and participating ground-based
observatories will take place from 01:25 UT to shortly
before 23:50 UT on 93/05/24 (May 24th). The photometric observations
on AD Leo will be used to ascertain the times, shapes, color
dependencies and durations of optical flares to compare with
the spectral and temporal variations observed at X-ray wavelengths.
Spectroscopic observers should concentrate on the H-alpha, He D3 and
Ca IRT regions. Photometric observers with high time resolutions (less than
tens of seconds) are requested to monitor AD Leo in one or more filters.
If performing broad-band photometry, the shorter wavelength filters are
requested.
For observers with time resolutions on the order of minutes, the
smaller flares, lasting in total duration around 1 minute, will not
be well determined by these observations. However, the hour time scale
flares are still of great interest during this campaign. Therefore,
these observers are requested to observe in multiple colors (such as
UBV filters) and observe sky (for photoelectric observers)
and comparison stars as required by sky conditions.
________
The suggested AD Leo comparison star is SAO 81274=HD 89196=BD+20 2460.
Spectral class = K2
R.A. (2000) = 10h 17m 45.7s R.A. (1950) = 10h 15m 01.3s
Dec. (2000) = 20d 00' 12.9" Dec. (1950) = 20d 15' 14.3"
V mag = 8.067
(U-B)=+1.792, (B-V)=+1.561, (V-R)=+1.250, (R-I)=+1.006 (Rucinski 1981 AA 31,363)
_______________
The variable star, AD Leo=SAO 81292=BD+20 2465
Spectral class = M4.5Ve
R.A. (2000) = 10h 19m 36.4s R.A. (1950) = 10h 16m 55.8s
Dec. (2000) = +19d 52' 12.0" Dec. (1950) = 20d 07' 22.0"
V mag = 9.39
(U-B)=+1.10, (B-V)=+1.54, (V-R)=+1.59, (R-I)=+1.75
___________________
Photometric standard = 40 Leo=SAO 99065=HD 89449=HR 4054
Spectral Class = F6IV
R.A. (2000) = 10h 19m 44.9s R.A. (1950) = 10h 17m 01.0s
Dec. (2000) = +19d 28' 26.1" Dec. (1950) = +19d 43' 31.2"
V mag = 4.80
(U-B)=+0.01, (B-V)=+0.45, (V-R)=+0.45, (V-I)=+0.68
===================
The dwarf nova SS Cyg is scheduled to be observed by ASCA starting
at 20:58 UT on 93/05/26 and ending shortly before 19:15 UT on 93/05/27.
Spectroscopic observations should contain the Balmer series and 4686A
(with a suggested resolution of at least 2-5 A).
The goals for the SS Cyg photometry include:
1. Determining the outburst state of SS Cyg during the ASCA observations
2. Determining correlations between X-ray flaring events and optical flares
3. Searching for Quasi-periodic oscillations in the SS Cyg light curves
The chosen photometric comparison stars are shown below.
SS Cyg comparison star:
SAO 51224=BD +42 4190
Spectral Class = K2
R.A. (2000) = 21h 43m 08.8s R.A. (1950) = 21h 41m 10.7s
Dec. (2000) = +43d 34' 59.9" Dec. (1950) = +43d 21' 13.6"
V mag = 8.50, (B-V)=+1.12
_____________________
The variable, SS Cyg, is located at
SS Cyg=BD+42 4189a=HD 206697
R.A. (2000) = 21h 42m 42.3s R.A. (1950) = 21h 40m 44.5s
Dec. (2000) = +43d 35' 08" Dec. (1950) = +43d 21' 23"
V mag = between 8 and 12 (currently rising toward outburst peak)
_____________________
SS Cyg check star:
BD+42 4186
Spectral Class = F0
R.A. (2000) = 21h 42m 20.2s
Dec. (2000) = +43d 34' 3.2"
V mag = 9.80
(B-V)=+0.38 (Hopp & Witzigmann 1981, A&A 89, 227)
__________________
Finder charts for SS Cyg are available in Bruch et al. (1987, A&A Suppl. Ser.
70, 481), Hopp (1979, IBVS 1633) and Downes & Shara (1993, PASP 105, 127).
The SS Cyg comparison star is marked as "E" in the chart of Hopp(1979), the
check star is "D" in the chart of Hopp (1979).
_____________________
Interested observers should contact Craig Robinson at robinson@astro.psu.edu.
-Craig Robinson
=========================================================
----- Begin Included Message -----
>From aavso@cfa0.harvard.edu Fri May 21 17:30:42 1993
21 May 1993
Message for MultiLink:
The dwarf nova SS Cygni, scheduled to be observed with ASCA starting May 26,
has started to brighten, as indicated by the observations below reported by
AAVSO observers:
May 15.69 UT 11.8 M. Yamada, Ishikawa, Japan
15.72 11.7 K. Hirosawa, Inazawa, Japan
15.78 11.7 M. Yamada, Ishikawa, Japan
16.01 12.3 G. Poyner, Birmingham, England
17.02 12.0 P. Schmeer, Bischmisheim, Germany
17.32 11.5 D. York, Abiquiu, NM
18.67 11.0 Y. Sekino, Kanagawa, Japan
19.06 11.0 L. Szentasko, Budapest, Hungary
19.07 10.8 P. Schmeer, Bischmisheim, Germany
19.25 10.8 M. Novak, Ennis, TX
19.35 10.3 P. Collins, Scottsdale, AZ
20.28 9.9 D. York, Abiquiu, NM
20.34 9.8 R. Royer, Lakewood, CA
Approximately 450 AAVSO observers have been alerted to the scheduled ASCA
observations of SS Cygni, and they will continue monitoring this star.
We will communicate their observations of SS Cygni as they are reported to
AAVSO Headquarters.
Janet A. Mattei
Director, AAVSO
aavso@cfa0.harvard.edu
----- End Included Message -----
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