A trip past the sun may have selectively altered the production of one form of water in a comet – an effect not seen by astronomers before, a new NASA study suggests.
Astronomers from NASA’s Goddard Space Flight Center in Greenbelt, Maryland, observed the Oort cloud comet C/2014 Q2, also called Lovejoy, when it passed near Earth in early 2015. Through NASA’s partnership in the W. M. Keck Observatory on Mauna Kea, Hawaii, the team observed the comet at infrared wavelengths a few days after Lovejoy passed its perihelion – or closest point to the sun.
Scientists from NASA’s Goddard Center for Astrobiology observed the comet C/2014 Q2 – also called Lovejoy – and made simultaneous measurements of the output of H2O and HDO, a variant form of water. This image of Lovejoy was taken on Feb. 4, 2015 – the same day the team made their observations and just a few days after the comet passed its perihelion, or closest point to the sun.
This February will feature a very close approach of Comet 45P/Honda–Mrkos–Pajdušáková. The comet will pass about 0.08AU (11.9 million km or 7.4 million miles) from Earth on February 11th, making it an easy telescopic object, and a marginal naked eye comet at around 6th magnitude.
This is a short period comet with an orbit only 5.25 years long. At aphelion it orbits out very close to Jupiter, while at perihelion it is well inside the orbit of Venus. As such it may occasionally pass very close to Earth.
The comet itself is rather interesting. Discovered in 1948 the comet has been a the frequent target of scientific observation as it may pass quite close to Earth. In 2011 it passed about 0.06AU from Earth and was the target of radar observations.
Currently in the evening sky the comet is sinking into the sunset rather rapidly. It will pass by the Sun around the end of January to appear in the morning sky. It will rise rapidly above the dawn, by February 5th it will be rising at 3:22am, about four hours before the Sun. On the day of close approach, February 11th, the comet will rise well before midnight in the northern sky.
The comet is predicted to remain quite bright, around 7th magnitude or better for all of January and most of February, possibly peaking at around 6th magnitude near close approach to the Earth. As this is a well observed comet these magnitudes are likely to be reasonably accurate.
Of course any comet getting this close to us will catch the attention of the doomsday preachers and assorted apocalyptic predictions. Comet 45P is already a bit of a YouTube celebrity with quite a few videos filled with dire predictions.
I predict that we will have a pretty comet in the new year’s sky to provide a nice target for telescopic observations and astrophotographers. I would suggest making a point to get out and observe this comet as it passes by.
A team led by astronomers from the Jagiellonian University in Krakow, Poland, recently used the W. M. Keck Observatory in Hawaii to observe and measure a rare class of “active asteroids” that spontaneously emit dust and have been confounding scientists for years. The team was able to measure the rotational speed of one of these objects, suggesting the asteroid spun so fast it burst, ejecting dust and newly discovered fragments in a trail behind it. The findings are being published in Astrophysical Journal Letters on March 20, 2015.
Unlike the hundreds of thousands of asteroids in the main belt of our solar system, which move cleanly along their orbits, active asteroids were discovered several years ago mimicking comets with their tails formed by calm, long lasting ice sublimation.
Then in 2010 a new type of active asteroid was discovered, which ejected dust like a shot without an obvious reason. Scientist gravitated around two possible hypotheses. One states the explosion is a result of a hypervelocity collision with another minor object. The second popular explanation describes it as a consequence of “rotational disruption”, a process of launching dust and fragments by spinning so fast, the large centrifugal forces produced exceed the object’s own gravity, causing it to break apart. Rotational disruption is the expected final state of what is called the YORP effect – a slow evolution of the rotation rate due to asymmetric emission of heat.
Sunday night I shot a wide-field image of the comet as it passed near the Pleiades star cluster. I am somewhat disappointed by the image. The skies over Waikoloa are just not conducive to wide-field imaging. And with a couple scheduled mountain days I did not have the option to take the gear up to where conditions are better. Not and get any sleep. Still, it is not a total disaster…
The first good night for comet imaging since the moonlight has departed the evening sky. If is wasn’t clouds it was heavy haze and vog. With a good Saturday night I set up the ‘scope in the driveway and shot for a couple hours on comet C/2014 Q2 Lovejoy.
This is not a properly processed shot, rather just a quick stack of the longer exposures. The real image will be a few days before I can get about to processing it. Still, a lot of interesting detail in the tail…
Back on August 17th, Australian amateur astronomer Terry Lovejoy disocvered a very nice Christmas gift for us all to enjoy… A bright comet that we have now unwrapped and are able to enjoy through the new year.
Comet C/2014 Q2 Lovejoy is currently passing through perihelion. While closest to the Sun and the Earth it will be at its brightest during the first couple weeks of January. For northern hemisphere observers the comet is currently low in the southern sky and getting brighter each day.
You can not simply call this comet Lovejoy. Terry Lovejoy has been quite successful in catching comets, with five discoveries to his credit. As a result there are five comets that bear the name Lovejoy. To properly identify which comet you are referring to you should use the full designation, C/2014 Q2 Lovejoy, as clumsy as that is in conversation.
The comet passes through perihelion on January 30th of 2015. For earthbound observers it will be at its brightest during the first weeks of January, reaching near 4th magnitude. It is currently visible around 5th magnitude in the faint constellation of Columba south of Orion. It has been visible without optical aid for a few weeks, as long as you have access to a dark sky and know where to look. As it brightens it will be easily visible, even rather obvious. With binoculars the view will be even better, a bright fuzzball with a wispy tail.
One of the best parts is that this comet will be well placed for observing through its perihelion passage. Longtime comet observers are used to looking for comets in the sunset or in the dawn sky as they near perihelion. Comet C/2014 Q2 has a perihelion that is just outside of the Earth’s orbit, and happens to pass by just as our planet reaches that part of it’s orbit. This puts the comet high in the midnight sky. No trying to catch the comet in bright twilight before the Sun comes up.
The next thing you may note about the orbital diagram is that the comet has a high inclination to the ecliptic. Currently approaching from underneath the plane of the solar system, the comet will exit north of our Sun. The practical side of this, is that over the next few weeks the comet will move northwards across the sky, rising higher each night. While our friends down south have been enjoying nice views of the comet approaching perihelion, it is northern hemisphere observers that will be able to best view the comet after perihelion.
The path of comet Lovejoy is shown in the diagram included here. The comet is plotted for today, December 28th at 0:00h. There is also a tick mark for January 11th near the top of the chart. A sweep with binoculars along this path will quickly locate the comet. There are no deep sky objects along this path that are bright enough to be confused with the comet. See a bright fuzzball? You found it.
One issue will be the bright Moon. Currently a waxing half phase, the Moon will be full on January 4th. This will make spotting the comet much more difficult and completely drown out the faint tail. By 9th or 10th the Moon will have waned enough to make comet viewing much more successful.
As January fades, so will comet C/2014 Q2. By the end of the month the comet will slip below unaided eye visibility, while staying within reach of binoculars through April or so. Sky watchers will be able to follow the comet for months betond that with the aid of a telescope. Enjoy the comet while you can, 8,000 years will pass before this comet returns to the inner solar system.
Taking the material I acquired last weekend, you can process a single frame, or process an animation. To bring out the tail a little better I converted the two hours of frames into an animated GIF. I also converted the frame to black and white and inverted it to show the fine detail.
The results are encouraging. Now… How well will this comet photograph when at its brightest in a couple weeks?
The first real product of Saturday’s imaging session on Mauna Kea. Processing comet images is a challenge (actually I am using far less correct language while I work on it). The problem is that comets move rapidly against the star field. This creates all sorts of issues when attempting to assemble a final image.
The single frame shown here is he product of 28 light frames and thirty calibration frames. The light frames used in this image were each 4 minutes long, accounting for nearly two hours of exposure total. There were a few more, but a few had to be discarded due to wind-shake of the telescope during the exposure.
The image below is processed to align on the comet as it moves against the background stars. During the two hours of exposures the comet moved appreciably. The stars are somewhat suppressed by using a sigma reject combine, but they are still there. Processing like this allows the details in the tail to be seen.
With a set of images running for two hours taken without interruption other things can be done. One possibility is that these images can be animated, leading to another interesting product… Up next!
It has been a while since the last good photographic comet. Since comet ISON disintegrated at perihelion a year ago, we have had few opportunities to get a really nice comet photo. It is the surprise of comet C/2014 Q2 Lovejoy that changed this.
Better yet… The comet is well placed for photography in the late evening and early morning sky. While fellow sky watchers on the south side of our planet have been enjoying the comet as it has brightened, for most northern hemisphere observers it is still rather low. In the past couple weeks it has moved far enough north that it is now nicely positioned to observe from Hawaiʻi. I have been following the comet for a while, catching it in binoculars from the house. We showed it to students of Paʻauilo Elementary in club telescopes as they camped out at the Kilohana Girl Scout Camp earlier this week.
Unfortunately it is still low enough that my neighbor’s trees prevent me from photographing it from the driveway. Thus I took the opportunity to pack up the ‘scope and head for Hale Pohaku and the Mauna Kea Visitor Information Station for a night of photography.
The Mauna Kea VIS is busier than ever, the numbers of tourists coming to this free show just continued to increase. Parking is now a major issue, with even the lower gravel lots full of visitor vehicles. Fortunately, with some discussion and name dropping, the rangers allowed me and my vehicle past the barricades into the main lot so I could set up just off the patio. I would be entertaining guests at the telescope and answering questions all evening, becoming part of the show.
Stayed up late tonight to check on a few things in the sky. Firstly the Geminid meteor shower, which is peaking nicely. At least 100ZHR and bright enough to be nicely visible, even against the light of a bright gibbous moon.
The second item I wanted to see was comet C/2014 Q2 Lovejoy, now climbing higher in the sky as it swings northwards. It is currently somewhat low in Puppis, but getting higher each night as it moves nearly due north against the constellations. Currently it is an easy binocular object at around 7th magnitude. A quick sweep with my 9×50’s picked it up without effort halfway between Adhara and Canopus.
It is forecast to reach around 5th magnitude over the next month. Peak magnitude should occur near the new year while the comet is in Lepus. We placed and quite bright, I will be arranging to get a few photos of this comet through the new year!