Monitoring of V2487 Oph requested

PTS

AAVSO Alert Notice 556

October 4, 2016

Monitoring of V2487 Oph requested


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,https://www.aavso.org/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 (https://www.aavso.org/observing-campaigns). 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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