Alert Notice 652: Monitoring of nova-like variables in support of Chandra observations

October 11, 2018: Dr. Koji Mukai (NASA-Greenbelt Space Flight Center) has requested AAVSO assistance in monitoring several nova-like variables in support of upcoming Chandra observations. The first target, KQ Mon, is scheduled to be observed with Chandra during the week of 2018 October 15-22.

Dr. Mukai writes: "We think we know how dwarf novae behave in X-rays, through various campaigns (famously that one on SS Cyg in outburst that Janet Mattei [and AAVSO observers] was heavily involved in, with Pete Wheatley and Chris Mauche, 2003MNRAS.345...49W): they are X-ray bright in optical quiescence, and fainter and softer in X-rays during outburst. In the optical, we think of nova-likes as systems in permanent outburst — but in X-rays, they don’t quite resemble dwarf novae in outburst. In fact, we haven’t seen a clear pattern, when we made X-ray observations of nova-like systems at various optical magnitudes. This Chandra program is part of an effort to look for patterns and to understand their X-ray emission."

The targets in the list below will all be observed with Chandra, but to date only KQ Mon has been scheduled.

Observers are asked to obtain "a few measurements within a couple of weeks of the Chandra observations". Thus, for KQ Mon, observations from now through October 31 are requested. V filter is optimal. Visual observations are welcome.

Dr. Mukai reports that the targets are being treated as "pool targets", which means that any of them could be scheduled at short notice. Therefore, although KQ Mon is the primary target now, an occasional snapshot of the other objects would be good in order to provide ongoing context.

Name RA (2000) Dec (2000) Type Range
1SWASP J022916.91-395901.4 02 29 16.95 -39 59 01.7 NL/VY 12.8-16.7 V
KQ Mon 07 31 21.13 -10 21 49.4 NL 12.5-13.7 vis
EC 21178-5417 21 21 26.53 -54 04 34.6 NL+E 13.4-15.2 CV
LQ Peg 21 36 19.14 +11 40 54.6 NL/VY 14.3V-17.0CV
UU Aqr 22 09 05.70 -03 46 17.5 EA+NL: 12.85-15.5V
V378 Peg 23 40 04.33 +30 17 47.7 NL 13.6-14.4V

Charts with comparison star sequences for each of the targets above may be created using the AAVSO Variable Star Plotter (VSP).

Please submit observations to the AAVSO International Database using the names given in the table.

AAVSO Forums: This campaign is the topic of the AAVSO Campaigns and Observation Reports forum thread
the Cataclysmic Variables forum thread

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

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