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Alert Notice 556: Monitoring of V2487 Oph requested

October 4, 2016: Dr. Ashley Pagnotta (Louisiana State University) has requested AAVSO assistance in monitoring the recurrent nova V2487 Oph in order to catch and observe its next outburst.

Dr. Pagnotta writes: "V2487 Oph is a recurrent nova that was first seen to erupt in 1998. During a search of the Harvard College Observatory plate archives for previous eruptions, we found one that was recorded in 1900. Based on the speed and magnitude of the eruption, and the coverage of the archival plates and other detection sources, we calculated how often V2487 Oph would have to erupt for us to have actually detected one random outburst on the plates, which is about once every 18-20 years. (For more, see http://adsabs.harvard.edu/abs/2009AJ....138.1230P) As we are now 18 years from the previous (1998) eruption, we request regular AAVSO observations to help us detect the next eruption of V2487 Oph.

"The predicted recurrence time for V2487 Oph is not as precisely known as that for U Sco, so we are not requesting as intense of an effort as we did in 2009. Because V2487 Oph is a very fast nova, however, we are requesting a high cadence [when the outburst occurs. Previous outbursts have been as bright as V=9.5.]...Once the eruption has been confirmed (likely by other AAVSO observers, thanks to the flexibility of your observing programs), we will notify collaborators and invoke ToO observations to observe the eruption as comprehensively as possible.

"For the initial detection observations, filter choice is not critical, although V or Clear would make it slightly easier to compare to the known quiescence value of V=17.5. If observing in other filters, it is important to consider color terms before reporting an early-stage outburst. Following the detection of the eruption, fast multi-band (if possible) photometry will help us define the light curve, but any observations would be useful, as long as V2487 Oph itself is well-detected and not saturated."

Observers are requested to make nightly observations in V or Clear once or twice a night and report their observations. If V2487 Oph is brighter than V=17.5, please report the observation(s) to the AAVSO immediately and switch to multi-color (UBVRI or Sloan equivalents; Clear if other filters are not available) and high (fast) cadence time-series - exposures of a few minutes, with a S/N of at least 40-50. The fast effects the PI's are looking for are on the order of tenths of a magnitude. Report observations as soon as possible.  

Please continue at high cadence until the decline is underway. Time-series observations during the decline are not absolutely essential, but they would be useful to continue to look for flares and the late time dips that were seen in U Sco around days 41-61. Nightly observations as before should be continued until the star has faded to V=17.5, and then for two weeks more.

Coordinates (2000.0): R.A. 17 31 59.81  Dec. -19 13 55.6

Charts with a comparison star sequence for V2487 Oph may be created using the AAVSO Variable Star Plotter (VSP).

Please submit observations to the AAVSO International Database using the name V2487 OPH.

This campaign is being followed on the AAVSO Observing Campaigns webpage. A thread has been created on the Campaigns and Observation Reports forum at (https://www.aavso.org/content/V2487-oph-observing-campaign).

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

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