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Sun, 23 Jul 2017 - R Coronae Borealis is edging brighter again

There was a time when observers would be encouraged to monitor R Coronae Borealis (R CrB) on a regular basis to check for any sudden fades.  The "standard pattern" was that R CrB would spend most of its time near magnitude 6.0 but at times, unpredictable in advance, it would start to fade.  Over the weeks which followed it would sometimes fade by just a magnitude or two, but on other occasions would produce a more dramatic fade, possible by as much as nine magnitudes.  On each occasion, however, it would return back to maximum. In most cases this would happen after an interval of a few months, but in exceptional cases there might be a longer delay of a year or two.

The fade that started in mid 2007 was different, however. The fade of nine magnitudes was not that unusual. What was unusual was that R CrB stayed faint year after year.  There were occasional short lived brightenings of a few magnitudes, but after each one it would fade back down again. Not until the autumn of 2014 did a brightening return R CrB to binocular visibility.  However, this one again fell short, peaking near magnitude 7.0 in early March 2015.  By late June it was back at minimum once more.

The most recent recovery began in mid 2016.  By November R CrB was visible in binoculars.  In early 2017, however, it seemed to be "running out of steam" - near magnitude 7.5 - raising fears that it would soon plummet in brightness again.

These fears were not be be realised.  Towards the end of May, there were signs that R CrB was starting to resume its brightening.  The subsequent rise in brightness has been slow, but by July it was around half a magnitude brighter.  R CrB is still nearly a magnitude below its "normal" maximum level, but maybe, just maybe, this time it will finally get there.

More information about R Coronae Borealis, including a finder chart, can be found in  this guide


Added by: Tracie Heywood