December 17, 2009: Dr. Axel Schwope (Astrophysikalisches Institut Potsdam) requests time-series monitoring of the magnetic cataclysmic variable V405 Pegasi, beginning 2009 December 28 (JD 2455193.5) and continuing through 2009 December 30 (JD 2455196.5). These observations are requested in support of a planned XMM-Newton observation of V405 Peg on 2009 December 29 beginning at 18:51 UT (JD 2455195.2854) and continuing for 12.5 hours. Observers are asked to provide intensive coverage during the three day window centered on the XMM-Newton observation to provide information on the activity state of V405 Peg, to improve the orbital ephemeris, and to provide optical data that will help constrain the spectral energy distribution of this poorly understood cataclysmic variable.
The primary filters for this observation are Johnson B and Cousins I, but all observations will be useful for determining the orbital ephemeris. V405 Peg may show both orbital modulation as well as changes in its activity level. Approximate magnitudes are Ic ~ 14.2 with ~ 0.1 magnitude orbital variations, and B between 16.0 and 18.0, with the brighter magnitude being the active state. The orbital period is approximately four hours, and observers are asked to obtain at least ten and preferably more data points per cycle in each filter. Please use exposure times that provide S/N of at least 20 in both the comparison and target stars but short exposure times are preferred to detect flickering and other short-timescale variations. If you cannot obtain sufficient signal to noise in B, please concentrate on Ic. Fully transformed magnitudes will greatly aid in the determination of the spectral energy distribution, and transformation and extinction correction is encouraged.
V405 Peg is located at the following (J2000) coordinates: RA: 23:09:49.15 , Dec: +21:35:17.4
Please submit data to the AAVSO using the name "V405 PEG". Observers may also send data directly to Dr. Schwope at (aschwope AT aip.de).
This AAVSO Alert Notice was prepared by M. Templeton.