Skip to main content

Alert Notice 424: Monitoring and Study of V2672 Oph

September 14, 2010: V2672 Oph (Nova Oph 2009) was discovered by Koichi Itagaki in outburst on August 16, 2009 (see AAVSO Alert Notice 402 and IAUC 9064).  It peaked at about magnitude 12, and rapidly faded.  Low- and medium-resolution spectroscopy showed broad, prominent H_alpha emission with FWHM 11500 km/s on top of a featureless, but very red, continuum.

The position of V2672 Oph (17:38:19.68, -26:44:14.0 J2000) is less than three degrees from the galactic center.  The rapid fading (2 magnitudes in 2.3 days) indicates a very bright nova, and gives a distance of about 19 kpc (62,000 light years) - basically an equal distance on the other side of the galaxy from the Sun.  The large distance plus closeness to the galactic center is why the spectrum is so reddened; yet this must be a relatively transparent field in order to see the nova at all.

The spectrum and the light curve shape are very similar to the recurrent nova U Sco, which is believed to host a nearly Chandrasekhar mass limit white dwarf. Such massive white dwarfs are considered the progenitors for type Ia supernovae.  A paper by Ulisse Munari (Univ. Padua) and collaborators, soon to appear in MNRAS, suggests that V2672 Oph is also a recurrent nova, with a high probability of an outburst frequency more often than U Sco (one eruption every decade).  If confirmed, this would make V2672 Oph one of the most valuable cataclysmic variables to study.

Ulisse and I would like to enlist the aid of AAVSO observers to study V2672 Oph in three ways:

1) Archival research.  The central region of our Galaxy has been photographed a countless number of times.  Previous outbursts could have been recorded, but easily overlooked.  You may have personal images covering this region, and can at least give date and time with negative results.  A posting on the various deep-sky imaging mail-lists might produce other images of the region. Most of those can be quickly examined and negative limits submitted. Plate Stacks at major repositories can be checked.

2) Recalibration of your photometry from the August 2009 outburst.  We've added BVRI comparison stars, calibrated at Sonoita, to VSP/VSD.  Please update any observations that you submitted to the AAVSO so that everyone is on the same scale.

3) Future monitoring. If the recurrent nova classification is correct, this star will go into outburst again, likely within a few years. Since the known outburst was short, the monitoring needs to be consistent and nightly.  There may also be other activity on the star, including lower-amplitude outbursts.

We invite all observers to take part in any of the ways mentioned above. Non-detections should be submitted to the AAVSO International Database; positive detections of outbursts should be brought to our attention.  Thanks in advance for your time and effort on this project!

Arne Henden, arne@aavso.org
Ulisse Munari, ulisse.munari@oapd.inaf.it

-------------------------------------------

SUBMIT OBSERVATIONS TO THE AAVSO

Information on submitting observations to the AAVSO may be found at:
http://www.aavso.org/webobs

ALERT NOTICE ARCHIVE AND SUBSCRIPTION INFORMATION

An Alert Notice archive is available at the following URL:
http://www.aavso.org/alert-notice-archive

Subscribing and Unsubscribing may be done at the following URL:
http://www.aavso.org/observation-notification#alertnotice
AAVSO 49 Bay State Rd. Cambridge, MA 02138 aavso@aavso.org 617-354-0484