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S Dor

Special Notice #205: Rapid fading in the luminous blue variable S Doradus

April 15, 2010: Noel D. Richardson and Douglas R. Gies (Georgia State University) announced on 2010 April 14 (Astronomer's Telegram #2560) that S Doradus is currently fading in optical brightness, while its hydrogen Balmer line (H-alpha) brightness is increasing. The V-band magnitude of S Dor (as measured by ASAS-3; Pojmanski, G., 2002, AcA 52, 397) has been declining for more than a thousand days. The star began a more rapid decline earlier this year, and is now fainter than V=9.5.

Special Notice #293: S Dor campaign continued through 2012-2013 season

September 10, 2012:  Dr. Noel Richardson (Georgia State University) has requested that the observing campaign on the luminous blue variable prototype S Dor (AAVSO Alert Notice 453, AAVSO Special Notice #280) be continued through the 2012-2013 observing season.

Special Notice #280: HST UV spectroscopy observations of S Dor scheduled

May 9, 2012: We have been informed by Dr. Noel Richardson, Georgia State University, that the UV spectroscopy observations of S Dor to be made with the Hubble Space Telescope have been scheduled for

2012 MAY 11 from 21:21:55 UT to 23:55:04 UT.

During the 24 hours prior to and following the HST observations, as well as during them, please increase your visual/BVRI (or as many of these filters as you can) coverage from once per night to twice per night. Afterwards, please return to nightly observations until further notice.

Alert Notice 453: Monitoring of S Dor requested for multiwavelength campaign

February 23, 2012:  Dr. Noel Richardson, Georgia State University, has requested monitoring of the luminous blue variable (LBV) prototype S Doradus as part of a multiwavelength campaign he is coordinating to study the photosphere of this star. At present the observations planned include:

1. UV Spectroscopy from HST
2. Optical spectroscopy from CTIO and an amateur in Australia
3. Near-IR Spectroscopy from SOAR (pending approval)
4. Mid-IR photometry from Gemini (pending approval)

Alert Notice 440: PEP Observing Campaign on P Cygni

May 17, 2011:  Ernst Pollmann, an active spectroscopist in Germany and leader of Active Spectroscopy in Astronomy, has requested the assistance of AAVSO photoelectric photometry (PEP) observers in a campaign to observe the S Doradus variable P Cygni through the 2011 observing season.

PEP data are needed for correlation with spectra of P Cyg obtained by Ernst and other spectroscopists as they study this very interesting star.

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