THE AMERICAN ASSOCIATION OF VARIABLE STAR OBSERVERS
25 Birch Street, Cambridge, MA 02138 USA
BITNET: aavso@cfa8 SPAN: nssdca::cfa8::aavso
Tel. 617-354-0484 FAX617-3S4-0665
AAVSO ALERT NOTICE 143 (May 3, 1991)
MAJOR CAMPAIGN ON THE FLARE STAR 101420 AD LEONIS
A major campaign has been organized by astronomers at Havard-Smithsonian Center
for Astrophyics to observe the flare star 101420 AD Leonis (RA = 10h 16m 52s,
Dec = +20deg 07' 17", 1950) on May 07, 08, and 09, 1991, with the Hubble Space
Telescope, IDE, ROSAT, and GINGA satellites, the Very Large Array and Arecibo
radio telescopes, and ground-based facilities. The purpose of these multiwavelength
observations is to provide a comprehensive study of the dynamics and energetics
of stellar flares. AD Leo has flare activity lasting from about a minute to many
minutes. Flares are more prominent in shorter wavelengths.
We have been invited to participate in this major campaign by providing worldwide
coverage of visual observations. If possible, please observe AD Leo continuously
for periods of 10 to 15 minutes, as often as you can during the nights of May 01,
08, and 09. When reporting your data please give VERY accurate timing of your
observations (to four decimals places of the JD), particularly if you observe
flaring activity, i.e., brightening. When reporting the date and time of your
observations of non-flares in your monthly report, please use the following format:
Example: 10 minutes of observations on May 07, between 12:00 (midnight) GMAT
and 12:10 GMAT: 2448384.5000-.5167
Photoelectric photometry is very much recommended in U, B, and V. For standardizing
the photometry the following stars have been selected by the project astronomers
as standards:
SAO 81296 (RA. = 10h 17m 09s, Decl. = +20deg 39' 21", mv = 8.4) and
SAO 81313 (RA. = 10h 19m 11s, Decl. = +20deg 18' 23", mv = 8.93).
Please use the accompanying AAVSO "b" scale chart of AD Leo for your observations. The
standard stars for photometry are also shown on it.
SUPERNOVA 1991T IN NGC 4527
Recent observations of this supernova.include:
Apr 18.049 UT, 12.5 (P. Schmeer, Bischmisheim, Germany);
19.8424, 11.5 (F. Pujol, Madrid, Spain);
19.8424, 12.0 (J. Ripero, Madrid, Spain);
19.8944, 11.1 (D. Rodriguez, Madrid, Spain);
20.8424, 11.5 (T. Lozano, Madrid, Spain);
20.8424, 11.5 (Pujol);
20.99, 11.8 (A. Peretra, Cabo da Roca, Portugal);
21.44, 11.5 (C. Stephan, Sebring, FL);
21.8424, 12.0 (Ripero);
22.1243, 11.6 (G. Lubcke, Middleton, WI);
22.132, 11.6 (P. Steffey, Daytona Beach, FL);
22.9048, 12.0 (Rodriguez);
23.097, 11.4 (Steffey);
23.16, 11.7 (CCD PEP (V), H. Smith, Michigan State University);
23.8632, 11.8 (Ripero); 23.872, 11.7 (Schmeer);
24.0944, 11.3 (Lubcke);
24.1486, 11.3 (Lubcke);
24.872, 11.5 (Schmeer);
25.144, 11.5 (CCD PEP (V), Smith);
26.17, 11.0 (R. Royer, Lakewood, CA);
27.21, 11.3 (Royer);
28.0958, 11.3 (Lubcke);
28.25, 11.3 (Royer);
29.1, 11.3 (Steffey);
29.25, 11.3 (Royer);
30.1, 11.1 (Steffey);
30.47, 11.49 PEP (V), (A. Gilmore, Mt. John University Obs.);
May 1.886, 11.6 (Schmeer);
Accompanying is an AAVSO "e" scale chart of this supernova.
NOVA HERCULIS 1991
Recent visual observations include:
Apr 18.086 UT, 12.7 (P. Schmeer, Bischmisheim, Germany);
19.2, 13.0 (E. Halbach, Estes Park, CO);
21.088, 13.0 (Schmeer);
22.079, 13.1 (Schmeer);
22.17, 12.7 (A. Pereira, Cabo da Roca, Portugal);
23.33, 13.2 (J. McKenna, Upper Montclair, NJ);
24.5, 13.3 (Halbach);
26.31, 13.5: (R. DeMartino, West Haven, CT);
Accompanying is an "e" scale chart of N Her 91 with additional photoelectric
magnitudes provided by T. Harrison, Mt. Stromlo Observatory.
NOVA MENSAE 1991 IN THE LARGE MAGELLANIC CLOUD
Recent observations include:
Apr 19.98 UT, 11.8 (photographic minus UV filter, Liller);
24.975, 9.1 (ptg minus UV filter, Liller);
21.04, 10.4 (ptg minus UV filter, Liller);
21.99, 9.8 (ptg minus UV filter, Liller);
22.985, 9.5 (ptg minus UV filter, Liller);
23.76, 8.8 (T. Cooper, Benoni, S. Africa);
24.011, 9.3 (ptg minus UV filter, Liller);
24.73, 9.2 (Cooper);
24.77, 9.0 (D. Overbeek, Edenvale, S.Africa);
25.7, 9.3 (Overbeek);
26.7, 9.3 (Overbeek);
28.975, 10.2 (ptg minus UV filter, Liller);
30.37, 11.48 (PEP (V), A. Gilmore, Mt. John U. Obs., New Zealand);
30.984, 11.3 (ptg minus UV filter, Liller);
May 1.34, 11.95 (PEP (V), Gilmore);
Accompanying is an AAVSO "d" scale chart of N Men (LMC) 91.
The answering machine at Headquarters (617 354 0484) is kept on nights and weekends.
Please continue to call in your observations on the recent novae and supernova so
that we may relay them to the Central Bureau of Astronomical Telegrams.
Thank you very much for your efforts and astronomical contributions.
Clear Skies! Good Observing! Flares of AD Leo!
Janet A. Mattei
Director
---------------------------------------------------
SUBMIT OBSERVATIONS TO THE AAVSO
Information on submitting observations to the AAVSO may be found at:
http://www.aavso.org/webobs
ALERT NOTICE ARCHIVE AND SUBSCRIPTION INFORMATION
An Alert Notice archive is available at the following URL:
http://www.aavso.org/alert-notice-archive
Subscribing and Unsubscribing may be done at the following URL:
http://www.aavso.org/observation-notification#alertnotices
Please support the AAVSO and its mission -- join or donate today:
http://www.aavso.org/apps/donate