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AAVSO Alert Notice 414: Request for Observations of V405 Peg AAVSO HOME > publications > alert notice

AAVSO Alert Notice 414

Request for Observations of V405 Peg
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

Charts for V405 Peg may be plotted using AAVSO VSP:

For more information on this project, please see the website set up by
Dr. Schwope for observers:

Please submit data to the AAVSO using the name "V405 PEG".  Observers may
also send data directly to Dr. Schwope at (aschwope AT

This AAVSO Alert Notice was prepared by M. Templeton.


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