A Cometary Breakup

While Comet 168P Hergenrother may be a bit of a mouthful, it is the proper designation for an interesting comet. Discovered in 1998, the comet is one of dozens that orbit in the inner solar system. Normally inconspicuous objects, these comets orbit quietly, objects that only astronomers love, or even know about. You would normally have needed a substantial telescope to see 168P, shining very dimly at magnitude 15.5 at it’s brightest. A community of amateur astronomers keeps tabs on these comets, occasionally photographing them, updating the orbits.

As the comet approached perihelion during the beginning of October, it became apparent that something had happened. Several observers were reporting that the comet had brightened. Suddenly the comet was far brighter, eventually reaching near 8th magnitude, over 500 times brighter than expected. We have seen this sort of thing before, a cometary breakup. Observations from several large telescopes, including Gemini North here on Mauna Kea, showed that the comet has split into at least four pieces.

When a breakup occurs it exposes a great deal of fresh material and debris, dramatically adding to the supply of dust and gas in the coma and creating a far brighter object. It is not the comet itself we see, that is fairly small. It is the coma and tail, the cloud of dust and gas that reflects the sunlight and gives a comet the synonymous appearance.

Comet 168P Hergenrother currently sports a small fan shaped tail, easily visible in the telescope. We enjoyed this classic comet shape in the telescopes last new moon at the Mauna Kea VIS. Setting up a telescope and CCD camera last night allowed me to photograph the comet, appearing much the same as it did a few weeks ago.

Comet 168P Hergenrother
Comet 168P Hergenrother taken with a 28cm SCT and a CoolSNAP ES2 CCD camera at f/10, sum of 12x30s exposures binned 4×4

Postcard from the Summit – Walking to the True Summit

It has been many years since I last stood atop the summit of Mauna Kea, the true summit that is. A couple decades ago, while on vacation I walked to the summit as a tourist. All these years of driving past on the way to work, I have not stopped and taken the short walk to the summit of Mauna Kea from the road, until now.

Broken gear on a weekend, driving up the mountain by myself. Once the gear was fixed I was free to head back down. Without a vehicle full of guys just wanting to go home after a full day at work, I was free to stop and take a walk with the camera…

Trail to the Summit
The trail to the summit of Mauna Kea outlined with stone

Swinburne Team on Keck Discovers Farthest Supernova Ever

W. M Keck Observatory press release…

Two ‘super-luminous’ supernovae — stellar explosions 10–100 times brighter than other supernova types — have been detected in the distant Universe, using the W.M. Keck Observatory on the top of Mauna Kea in Hawaii. The discovery, reported online in Nature this week, sets a record for the most distant supernova yet detected, and offers the rare possibility of observing the explosions of the first stars to form after the Big Bang.

Early Supernova
Simulation of a galaxy hosting a super-luminous supernova and its chaotic environment in the early Universe. Credit: Adrian Malec and Marie Martig (Swinburne University)
“The type of supernovae we’ve found are extremely rare,” said Jeff Cooke, astrophysicist at Swinburne University of Technology, whose team made the discovery. “In fact, only one has been discovered prior to our work. This particular type of supernova results from the death of a very massive star (about 100 – 250 times the mass of our Sun) and explodes in a completely different way compared to other supernovae. Discovering and studying these events provides us with observational examples to better understand them and the chemicals they eject into the Universe when they die.”

Super-luminous supernovae were discovered only a few years ago, and are rare in the nearby Universe. Their origins are not well understood, but a small subset of them is thought to occur when extremely massive stars undergo a nuclear explosion triggered by the conversion of photons into electron–positron pairs. Such events are expected to have occurred more frequently in the early Universe (at high redshift), when massive stars were more common. This, and the extreme brightness of these events, encouraged Cooke and colleagues to search for super-luminous supernovae at redshifts, z, greater than 2, when the Universe was less than one-quarter of its present age.

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Comment Spam

Comment spam is always a problem when maintaining a blog, a constant battle. Generally one my readers do not see, as I have to manually approve any comment from a new commenter. As I have it setup now, once I approve a comment from a particular reader, any further comments they make get posted immediately. I do try to make it easy for my loyal readers.

But this does leave a list of messages in the approval que each day, until recently this was anywhere from a few to a dozen. In the last week the number has soared, to 30-50 spam comments each day. It becomes a real chore to delete them all.

Time to take the next step in the armaments race. I had two choices, disallow anything using an @gmail.com address as verification, or install a more sophisticated filtering software.

Just about every spam comment in the que is using a Gmail address for verification. So are a few of my loyal readers, folks I really do not want to cut off from commenting. These mail accounts are really convenient, for regular folks and the spammers.

Take the other choice? I will attempt to use a spam detection plugin for WordPress called Askimet. As of today it is installed and active, a test.

I do worry that legitimate comments will be lost. Please look to see your comment posts properly, if it does not, drop me a line and I will see if I can add you to the whitelist.