Long Term Monitoring of the Recurrent Nova U Scorpii

Spitzer Space Telescope (Courtesy: NASA)

This observing campaign was announced in Alert Notice 367

Dr. Bradley E. Schaefer (LSU) requests long-term, nightly monitoring of the recurrent nova U Scorpii. This nova, with a recurrence time of approximately ten years, last erupted in 1999. It is believed due for another outburst in 2009 -- Schaefer predicts the outburst will occur in 2009.3 +/- 1.0 year.

Schaefer is using this object as a test of a theory outlined in his 2005 paper on possible triggers for nova eruptions. It is hoped that long-term monitoring by AAVSO observers will provide rapid notification of outbursts and a photometric record of U Sco prior to and throughout the next outburst. Several ground and space-based observatories including the Hubble Space Telescope, Swift, and the Spitzer Space Telescope will be used to observe U Sco when it erupts, and your observations may be used to trigger these observations.

Artist's conception of a cataclysmic variable system (Courtesy: A. Beardmore, University of Leicester)

AAVSO observers are asked to add this object to their list of monitored objects. Both visual and CCD observers are asked to monitor this star for outbursts, and upon detection, to report observations as quickly as possible to the AAVSO. They are then asked to follow the outburst throughout the expected rapid rise and decline. CCD observers capable of detecting this star in reasonable time are asked to obtain occasional positive detections as a record of U Sco's behavior prior to outburst. U Sco is extremely faint outside of outburst, so positive observations will be difficult. "Fainter-than" observations are also valuable as they can confirm the object is not in outburst.

This object lies very close to the ecliptic, and solar interference is severe near conjunction. Observers are asked to obtain observations of U Sco as close to the Sun as possible, particularly when it is a morning object; outbursts typically last for only a few months, and it is possible that an entire outburst may be lost during conjunction.

Bradley Schaefer informs us that the object was marginally detected within the past week using the ROTSE IIIb telescope in Texas; U Sco was at a magnitude consistent with normal quiescence. Therefore it is unlikely that U Sco went into outburst and declined during the recent solar conjunction, and is still likely to go into outburst during the next two years. U Sco is currently a morning object, and observations made during its morning apparition are strongly encouraged.

Charts

Charts for a variety of scales may be generated with VSP

Light Curves

The most recently-submitted observations are available via the Quick Look Data page.

Light curve as of 2008 January 21: