Special Notice #332: Observations of IR Com crucial now through February 8

February 5, 2013: Further to AAVSO Alert Notice 471 (http://www.aavso.org/aavso-alert-notice-471) and AAVSO Special Notice 330 (http://www.aavso.org/aavso-special-notice-330), HST/COS is scheduled to observe IR Com on:

                                    IR Com   2013 February 8 00:38:46 through 05:57:49 UT

IR Com is an eclipsing SU UMa-type dwarf nova. According to observations in the AAVSO International Database, it reaches V magnitude 18-19 at minimum. IR Com can be as bright as 13.5 V at maximum.

Your observations are crucial now through February 7, as the HST planners will decide whether to observe IR Com based on them. They will need to know whether the system is in quiescence. They will likely make their decision early on February 7. Observations through February 8 at least are also extremely important for correlation with the HST/COS data.

As instructed in AAVSO Alert Notice 471, for CCD observers, simultaneous photometry [shortly before, during, and after the HST observations] would be ideal. For the magnitude estimates, a nightly V measurement from now through the HST observations and a day beyond would be best. At 18-19 V at minimum, IR Com is likely too faint for positive visual observations at minimum. If positive visual observations are possible, however, they are welcome, as are visual fainter-than observations fainter than magnitude 15.0.

Coordinates for IR Com: R.A. 12 39 32.02  Dec. +21 08 06.4 (2000.0)

Charts may be created using the AAVSO Variable Star Plotter (http://www.aavso.org/vsp).

Please report observations as soon as possible to the AAVSO International Database using the names IR Com. If an outburst is detected, please report observations immediately.  Many thanks!

This AAVSO Special Notice was compiled by Elizabeth O. Waagen.


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