Comet 2012 X1 (LINEAR) brightens dramatically
BY MARK ARMSTRONG
Posted: 23 October 2013
There's never a dull moment where comets are concerned! In the thick of all the excitement and speculation over ISON comes the news that a run-of-the-mill comet, 2012 X1 (LINEAR), has undergone an outburst that has caused a 100-fold increase in its brightness, catapulting it from a predicted 14th magnitude to magnitude +8.5, within range of large binoculars and small telescopes. All this whilst 2012 X1 is still 443 million kilometers (275 million miles) from Earth and four months away from perihelion (closest to the Sun).
Following reports on Central Bureau Electronic Telegram (CBET) 3674 that H Sato of Tokyo had measured the comet's magnitude at +8.5, veteran UK amateur astronomer and secretary of the British Astronomical Association's (BAA) Comet Section, Denis Buczynski, imaged 2012 X1 on 21 October from his observatory in Aberdeenshire, Scotland.
"I imaged the comet this evening at 18:21 UT on the south-west horizon just before moonrise," he says. "The comet is in outburst and my image shows a circular disc-like form about two arcminutes in diameter with a curved jet-like structure at its centre. It has the appearance of a mini 17P Holmes [a comet that outburst in 2007]. How this outburst will develop over the next few weeks will be very interesting."
Denis and Richard Miles, another long-standing BAA observer, have processed Denis' image and examined the comet's coma. Richard likens this outburst to the outburst of comet 29P Schwassmann-Wachmann in February 2010, when it reached tenth magnitude.
The well-known and prolific comet observing and imaging team of Ernesto Guido, Nick Howes and Martino Nicolini remotely imaged the comet from New Mexico, USA, also on 21 October. Guido et al report that 2012 X1 has a 105-arcsecond coma with a sharp central condensation around 15 arcseconds in size. Romanian amateur astronomer Maximilian Teodorescu observed the comet on 22 October and confirmed its brightness and appearance. "It looked exactly like Comet Holmes back in 2007. I could not see the comet through the eyepiece of my 4.5-inch refracting telescope, but the camera detected it easily enough," he says.
Amateur observers worldwide fondly remember the incredible outburst of 17P/Holmes, six years ago to the month, when it brightened from a lowly 17th magnitude to a brilliant naked-eye magnitude of +2.8 within two days and its coma expanded from three to thirteen arcminutes. An estimated one percent of Holmes' mass was ejected. Whilst 2012 X1's outburst is not in the same league, it's still an exciting event for astronomers to monitor over the forthcoming nights.
Where to see the comet
From the UK
The coming months