Dark Energy Camera Takes Accidental Gigantic, Magnificent Picture of Comet Lovejoy

Oops! In a happy accident, Comet Lovejoy just happened to be in the field of view of the 570-megapixel Dark Energy Camera, the world’s most powerful digital camera. One member of the observing team said it was a “shock” to see Comet Lovejoy pop up on the display in the control room.

“It reminds us that before we can look out beyond our Galaxy to the far reaches of the Universe, we need to watch out for celestial objects that are much closer to home!” wrote the team on the Dark Energy Detectives blog.

On December 27, 2014, while the Dark Energy Survey was scanning the southern sky, C2014 Q2 entered the camera’s view. Each of the rectangular shapes above represents one of the 62 individual fields of the camera.

At the time this image was taken, the comet was passing about 82 million km (51 million miles) from Earth. That’s a short distance for the Dark Energy Camera, which is sensitive to light up to 8 billion light years away. The comet’s center is likely made of rock and ice and is roughly 5 km (3 miles) across. The visible coma of the comet is a cloud of gas and dust about 640,000 km (400,000 miles) in diameter.

The Dark Energy Survey (DES) is designed to probe the origin of the accelerating universe and help uncover the nature of dark energy by measuring the 14-billion-year history of cosmic expansion with high precision.

The camera just finished up the third, six-month-long season of observations, and the camera won’t be observing again until this fall.

You can download higher resolution versions of this image here.

Without the Moon, Comet Lovejoy is Magnificent

With the Moon rising later in the evening this weekend, astrophotographers have taken some spectacular pictures of Comet 2014 Q2 Lovejoy, which continues shine on! Enjoy a few photos here and check out more in Universe Today’s Flickr page.

Chris Schur from Payson, Arizona took the above image with a 80mm f/4.6 Zeiss APO and a ST10xme ccd camera.

Comet Lovejoy on February 8, 2015 seen with a 12.5" Newtonian from Payson, Arizona. Credit and copyright: Chris Schur.
Comet Lovejoy on February 8, 2015 seen with a 12.5″ Newtonian from Payson, Arizona. Credit and copyright: Chris Schur.
Comet C/2014 Q2 Lovejoy, Widefield view, false color. Feb 8, 2015. Credit and copyright: Joseph Brimacombe.
Comet C/2014 Q2 Lovejoy, Widefield view, false color. Feb 8, 2015. Credit and copyright: Joseph Brimacombe.

[caption id="attachment_118887" align="aligncenter" width="580"]Comet Lovejoy Q2, Feb 7, 2015. Credit and copyright: Cajun Astro on Flickr. Comet Lovejoy Q2, Feb 7, 2015. Credit and copyright: Cajun Astro on Flickr.

Comet Lovejoy Now at its Brightest: Images from Around the World

Last night was the first time I was able to spot Comet Lovejoy with unaided eyes. The latest images from our readers and dedicated astrophotographers confirm that now is a good time to see the comet, which is reaching maximum brightness at his week. Spaceweather.com reports that many experienced observers say the comet is now shining at magnitude +3.8. With clear, dark skies C/2104 Q2 is easily seen with binoculars.

Enjoy this gallery of recent images, and if you’ve taken an image, consider joining our Flickr pool and submitting it. We may use your image in an upcoming article!

Comet Lovejoy C/2104 Q2 cruising past the open star Cluster M45 “Pleiades” or “The Seven Sisters.” Credit and copyright: John Chumack.
Comet Lovejoy C/2104 Q2 cruising past the open star Cluster M45 “Pleiades” or “The Seven Sisters.” Credit and copyright: John Chumack.
Comet Lovejoy taken on January 15, 2015 from Singapore. Credit and copyright: Justin Ng.
Comet Lovejoy taken on January 15, 2015 from Singapore. Credit and copyright: Justin Ng.
Comet C/2014 Q2 Lovejoy in a widefield false color image taken on January 16, 2015 from New Mexico Skies. Credit and copyright Joseph Brimacombe.
Comet C/2014 Q2 Lovejoy in a widefield false color image taken on January 16, 2015 from New Mexico Skies. Credit and copyright Joseph Brimacombe.
Comet Lovejoy, C/2014 Q2, a wide binocular field west of M45, the Pleiades star cluster in Taurus, on January 15, 2015, shot from Silver City, New Mexico. The long blue ion tail stretched back for about 8°. Credit and copyright: Alan Dyer.
Comet Lovejoy, C/2014 Q2, a wide binocular field west of M45, the Pleiades star cluster in Taurus, on January 15, 2015, shot from Silver City, New Mexico. The long blue ion tail stretched back for about 8°. Credit and copyright: Alan Dyer.
Comet Lovejoy photographed from Torrance Barrens Dark-Sky Preserve (30 km from Gravenhurst, Ontario, Canada; 200 km north of Toronto) on January 13, 2015.  Credit and copyright: Michael Watson.
Comet Lovejoy photographed from Torrance Barrens Dark-Sky Preserve (30 km from Gravenhurst, Ontario, Canada; 200 km north of Toronto) on January 13, 2015. Credit and copyright: Michael Watson.
Comet Lovejoy as seen from Lahore, Pakistan on January 15, 2014, 10:30 pm local time. 35 single images stacked in DSS. Each 8 seconds, ISO 2000, f/5.6, edited in Photoshop. Credit and copyright: Roshaan Bukhari
Comet Lovejoy as seen from Lahore, Pakistan on January 15, 2014, 10:30 pm local time. 35 single images stacked in DSS. Each 8 seconds, ISO 2000, f/5.6, edited in Photoshop. Credit and copyright: Roshaan Bukhari
High resolution 3 panel mosaic of C/2014 Q2 on January 11, 2015. Field of view is approximately 3.5° x 2° and composed of three fields. Many fine streamers are visible emanating from the nucleus. Credit and copyright: SEN/ Damian Peach.
High resolution 3 panel mosaic of C/2014 Q2 on January 11, 2015. Field of view is approximately 3.5° x 2° and composed of three fields. Many fine streamers are visible emanating from the nucleus. Credit and copyright: SEN/ Damian Peach.
Comet LoveJoy photographed from Kosovo on January 13, 2015. Credit and copyright: Suhel A. Ahmeti.
Comet LoveJoy photographed from Kosovo on January 13, 2015. Credit and copyright: Suhel A. Ahmeti.
C2014 Q2 Lovejoy on January 13, 2015. Credit and copyright: Shahrin Ahmad.
C2014 Q2 Lovejoy on January 13, 2015. Credit and copyright: Shahrin Ahmad.
Comet Lovejoy on January 11, 2015. Credit and copyright: Henry Weiland.
Comet Lovejoy on January 11, 2015. Credit and copyright: Henry Weiland.
Wide angle shot of Comet Lovejoy with the constellation Orion, showing rich fields of red nebula, star clouds and dark nebula with the bright green naked eye comet. Credit and copyright: Chris Schur.
Wide angle shot of Comet Lovejoy with the constellation Orion, showing rich fields of red nebula, star clouds and dark nebula with the bright green naked eye comet. Credit and copyright: Chris Schur.
Comet Lovejoy traveling through Taurus. Imaged on January 12, 2015 from Bathurst, New South Wales. Credit and copyright: Wes Schulstad.
Comet Lovejoy traveling through Taurus. Imaged on January 12, 2015 from Bathurst, New South Wales. Credit and copyright: Wes Schulstad.
C2014 Q2 Lovejoy on January 7, 2015, taken from Bannister Green, England. Credit and copyright: Wendy Clark.
C2014 Q2 Lovejoy on January 7, 2015, taken from Bannister Green, England. Credit and copyright: Wendy Clark.

Weekly Space Hangout – Jan 9, 2015: Andy Weir of “The Martian”

Host: Fraser Cain (@fcain)
Special Guest: Andy Weir , author of “The Martian”
Andy was first hired as a programmer for a national laboratory at age fifteen and has been working as a software engineer ever since. He is also a lifelong space nerd and a devoted hobbyist of subjects like relativistic physics, orbital mechanics, and the history of manned spaceflight. “The Martian” is his first novel.

Guests:
Morgan Rehnberg (cosmicchatter.org / @cosmic_chatter)
Ramin Skibba (@raminskibba)
Brian Koberlein (@briankoberlein)
Dave Dickinson (@astroguyz / www.astroguyz.com)
Nicole Gugliucci (cosmoquest.org / @noisyastronomer)
Continue reading “Weekly Space Hangout – Jan 9, 2015: Andy Weir of “The Martian””

If You Can Find Orion, You Can Find Comet Lovejoy

Comet Lovejoy (2014 Q2) is now visible in the night sky, and while you’ll need binoculars or a low-power telescope to see it best, the perfect window of opportunity to see it for yourself is starting now! We’ve heard from some readers that they’ve had some trouble spying it, but photographer Brian Moran has snapped the perfect picture to show you EXACTLY where to look for the comet. All you need to do is look for the easy-to-find constellation of Orion, and swing your eyes to the right (about 20 degrees) and up slightly up.

Brian said he was having trouble finding Lovejoy, but perhaps it may have been because he was looking a little too close to Orion. “Orion is a great frame of reference, but all of the photos I saw online made it seem like it was closer to Orion than it actually is,” he said.

Comet Q2 Lovejoy is currently shining at 4th magnitude, and if you’ve got a really dark sky, you may be able to see it with the unaided eye. as our David Dickinson explained, this comet is now entering “prime time” evening sky viewing, as it is visible over the southern horizon at around 9:30 PM local time this weekend, then 8:00 PM on January the 15th, and just before 6:00 PM by January 31st.

Tonight (Thursday, January 8) we’ll have a “two-hour window of darkness between the end of twilight and moonrise for those of us in the world’s mid-northern latitudes. Each night after tonight the Moon rises nearly an hour later,” said Sky & Telescope’s Alan MacRobert.

Finder chart for Comet Lovejoy, C/2014 Q2, during January 2015. The dates are in Universal Time; the ticks are at 0:00 UT (7:00 p.m. on the previous date Eastern Standard Time). Click on the image for larger, print-friendly black-on-white PDF, courtesy of Sky & Telescope.
Finder chart for Comet Lovejoy, C/2014 Q2, during January 2015. The dates are in Universal Time; the ticks are at 0:00 UT (7:00 p.m. on the previous date Eastern Standard Time). Click on the image for larger, print-friendly black-on-white PDF, courtesy of Sky & Telescope.

While C/Q2 Lovejoy passed closest to Earth yesterday (January 7) at a distance of 0.47 a.u. (44 million miles; 70 million km), the comet should remain at about the same brightness as it crosses the sky into Taurus, Aries, and Triangulum, higher and higher in early evening. It will pass 8° west-southwest of the Pleiades on the evening of January 17th.

MacRobert also explained that although the comet is beginning to recede from us, its intrinsic brightness should still be increasing a bit. “That’s because it doesn’t reach perihelion (its closest to the Sun) until January 30th (at a rather distant 1.29 a.u. from the Sun),” he said. “By that date the comet should finally be fading slightly from Earth’s point of view. And in late January the Moon returns; it’s first-quarter on the 26th.”

Here are some great images of Comet Lovejoy taken by Universe Today readers. Be sure to check out our Flickr group for more great images! We have nearly 1,500 members and new photos are added every day. And if you take an astrophoto, join our group and submit your photos! We may use your image in an upcoming article!

A wide-angle shot of Comet Lovejoy 2014 Q2 above snow-covered trees. Taken as it neared Orion on January 6, 2014.  Credit and copyright: Marion Haligowski.
A wide-angle shot of Comet Lovejoy 2014 Q2 above snow-covered trees. Taken as it neared Orion on January 6, 2014. Credit and copyright: Marion Haligowski.
C/2014 Q2 Lovejoy on 7th January 2015. A couple of satellites managed to sneak in the image, too! Credit and copyright: JP Willinghan.
C/2014 Q2 Lovejoy on 7th January 2015. A couple of satellites managed to sneak in the image, too! Credit and copyright: JP Willinghan.
Comet C/2014 Q2 Lovejoy Passes Messier 79 Narrowfield C False Color, taken on Dec 29, 2014, from New Mexico Skies using a 43-cm CDK telescope and STXL-6303 camera on a PME II mount. Credit and copyright: Joseph Brimacombe.
Comet C/2014 Q2 Lovejoy Passes Messier 79 Narrowfield C False Color, taken on Dec 29, 2014, from New Mexico Skies using a 43-cm CDK telescope and STXL-6303 camera on a PME II mount. Credit and copyright: Joseph Brimacombe.
A monochrome image of Comet Lovejoy (2014 Q2) taken on December 31, 2014. Credit and copyright: Damian Peach.
A monochrome image of Comet Lovejoy (2014 Q2) taken on December 31, 2014. Credit and copyright: Damian Peach.
Comet Lovejoy, as seen on December 29, 2014 at around 12.30AM SGT from Singapore. Also visible is spiral galaxy NGC1886, seen to the left of the coma. Total exposure time is 12 minutes. Credit and copyright: Justin Ng.
Comet Lovejoy, as seen on December 29, 2014 at around 12.30AM SGT from Singapore. Also visible is spiral galaxy NGC1886, seen to the left of the coma. Total exposure time is 12 minutes. Credit and copyright: Justin Ng.
Comet Lovejoy as seen from Aldalucia, Spain on December 30, 2013. Credit and copyright: Ian Sharp.
Comet Lovejoy as seen from Aldalucia, Spain on December 30, 2013. Credit and copyright: Ian Sharp.
Comet Lovejoy Passing Globular Cluster M-79. Credit and copyright: Greg Redfern.
Comet Lovejoy Passing Globular Cluster M-79. Credit and copyright: Greg Redfern.
A two-part panorama of Comet 2014 Q2 Lovejoy as seen from Payson, Arizona on December 27, 2014. Credit and copyright: Chris Schur
A two-part panorama of Comet 2014 Q2 Lovejoy as seen from Payson, Arizona on December 27, 2014. Credit and copyright: Chris Schur

Comet Finlay in Bright Outburst, Visible in Small Telescopes

Short-period comet 15P/Finlay, which had been plunking along at a dim magnitude +11, has suddenly brightened in the past couple days to +8.7, bright enough to see in 10×50 or larger binoculars. Czech comet observer Jakub Cerny and his team photographed the comet on December 16th and discovered the sudden surge. Wonderful news!

While comets generally brighten as they approach the Sun and fade as they depart, any one of them can undergo a sudden outburst in brightness. You can find Finlay right now low in the southwestern sky at nightfall near the planet Mars. While outbursts are common, astronomers still aren’t certain what causes them. It’s thought that sub-surface ices, warmed by the comet’s approach to the Sun, expand until the pressure becomes so great they shatter the ice above, sending large fragments flying and exposing fresh new ice. Sunlight gets to work vaporizing both the newly exposed vents and aerial shrapnel. Large quantities of dust trapped in the ice are released and glow brightly in the Sun’s light, causing the comet to quickly brighten.

Some comets flare up dramatically. Take 29P/Schwassmann-Wachmann. Normally a dim bulb at 17th magnitude, once or twice a year it flares to magnitude 12 and occasionally 10!

Animated movie showing the expansion of the coma of Comet Holmes over 9 nights during its spectacular outburst in November. Credit: 3.6-meter Canada-France-Hawaii telescope on Mauna Kea / David Jewitt
Animated movie showing the expansion of the coma of Comet Holmes over 9 nights during its spectacular outburst in November 2007. Credit: 3.6-meter Canada-France-Hawaii telescope on Mauna Kea / David Jewitt

Whatever the reason, outbursts can last from days to weeks. It’s anybody’s guess how long 15P/Finlay will remain a relatively easy target for comet hungry skywatchers.  While not high in the sky, especially from the northern U.S., it can be seen during early evening hours if you plan well.

By pure good chance, Comet Finlay will track with Mars through December into early January. They'll make a remarkably close pair on the evening of December 23rd. This map shows the nightly position of the comet from Dec. 18th through Jan. 12th. Mars location is shown every 5 nights. Positions plotted for 6:15 p.m. (CST) 1 hour and 45 minutes after sunset. Stars shown to magnitude 8. Star magnitudes are underlined. Click to enlarge and print. Source: Chris Marriott's SkyMap software
By good luck, Comet Finlay will track with Mars through December into early January. On December 23rd, they’ll come together in a remarkably close conjunction. This map shows the nightly position of the comet from Dec. 18th through Jan. 12th. Mars’ location is shown every 5 nights. Positions plotted for 6:15 p.m. (CST) 1 hour and 45 minutes after sunset. Stars shown to magnitude 8. Star magnitudes are underlined. Click to enlarge and print for outside use. Source: Chris Marriott’s SkyMap software

Comet Finlay was discovered by William Henry Finlay from South Africa on September 26, 1886. It reaches perihelion or closest approach to the Sun on December 27th and was expected to brighten to magnitude +10 when nearest Earth in mid-January at 130 million miles (209 million km). Various encounters with Jupiter since discovery have increased its original period of 4.3 years to the current 6.5 years and shrunk its perihelion distance from 101 million to 90 million miles.

Comet Finlay appears considerably fainter in this pre-outburst photo taken on December 14th. Credit: Alfons Diepvens
Comet Finlay appears considerably fainter in this pre-outburst photo taken on December 14th. Credit: Alfons Diepvens

Looking at the map above it’s amazing how closely the comet’s path parallels that of Mars this month. Unlike Comet Siding Spring’s encounter with that planet last October, Finlay’s proximity is line of sight only. Still, it’s nice to have a fairly bright planet nearby to point the way to our target. Mars and Finlay’s paths intersect on December 23rd, when the duo will be in close conjunction only about 10? apart (1/3 the diameter of the Full Moon) for observers in the Americas. They’ll continue to remain almost as close on Christmas Eve. Along with Comet Q2 Lovejoy, this holiday season is turning out to be a joyous occasion for celestial fuzzballs!

To give you a little context to make finding Comet FInlay easier, use this wide-view map. A line from bright Vega in the western sky left through Altair will take you directly to Mars and the comet. This map shows the sky at nightfall tonight when the comet will be about 15 degrees high in the southwestern sky. Source: Stellarium
To give you a little context to make finding Comet FInlay easier, use this wide-view map. A line from bright Vega in the western sky left through Altair will take you directly to Mars and the comet. This map shows the sky at nightfall tonight when the comet will be about 15° high in the southwestern sky. Source: Stellarium

Lovejoy and X1 LINEAR: How to See Comets That Will Warm Up Your Mid-Winter Mornings

My hands are still cold from the experience, but there’s no denying the pleasure I felt at seeing C/2013 R1 Lovejoy and C/2012 X1 LINEAR through the telescope this morning.  Some comets fizzle, others fall apart, but these vaporous hunks have hung in there for months like steadfast friends that stick with you through hard times and good.While no longer visible with the naked eye, 50mm binoculars easily show it as a magnitude 7 fuzzy glow with a short, faint tail pointing up and away to the northwest.  I had no difficulty seeing it even with a last quarter moon glaring in the south.

Comets Lovejoy and X1 LINEAR are both moving across northern Ophiuchus. This map shows the sky facing east about 1 hour 45 minutes before sunrise shortly before the start of morning twilight. Detailed map below. Stellarium
Comets Lovejoy and X1 LINEAR are neighbors in northern Ophiuchus this month and next. This map shows the sky facing east about 1 hour 45 minutes before sunrise shortly before the start of morning twilight. Tick marks show the comets’ position every 5 days. Click to enlarge. Detailed map below. Created with Chris Marriott’s SkyMap software.

Rising around 3 a.m., Lovejoy is best placed for viewing just before the start of dawn when it climbs to about 30 degrees altitude in Ophiuchus. Lucky for us, Lovejoy will spend the next few mornings very close to the easy naked eye star 72 Ophiuchi, located 3 fists held at arm’s length to the lower right of brilliant Vega. It’s not often that a fairly bright comet passes this close to a helpful guide star. Don’t miss this easy catch. Soon the moon won’t be any trouble either as it skedaddles eastward and dwindles to a crescent in the coming mornings.

This deeper map shows stars to about magnitude 8. Although both comets appear to be getting lower every morning, the seasonal drift of the star to the west will keep them in good view for the next few months. Stellarium
This deeper map shows stars to about magnitude 8. Although both comets appear to be getting lower every morning, the westward seasonal drift of the stars will keep them in good view for the next few months. Click to enlarge. Created with Chris Marriott’s SkyMap software

Telescopic views of Lovejoy show a much diminished coma and tail compared to its heyday in early December. Still,  the nucleus remains bright and very condensed within the 3′ diameter gauzy coma; a faint and silky tail 2/3 of a degree long flowed across the field of view of my 15-inch (37-cm) reflector like a bride’s train. According to the excellent Weekly Information about Bright Comets site maintained by Seiichi Yoshida, Lovejoy should glow brighter than magnitude 8, what I consider the “bright” comet cutoff, through early February. Given that Lovejoy remains the brightest predicted comet visible till summer, show it some love the next clear night.

Comet C/2012 X1 LINEAR shows a green coma from fluorescing gases and a short tail in this photo made on Jan. 15, 2014. Credit: Rolando Ligustri
Comet C/2012 X1 LINEAR shows a green coma from fluorescing gases and a short tail in this photo made on Jan. 15, 2014. Credit: Rolando Ligustri

If Lovejoy’s a fading celebrity, X1 LINEAR suffered a mid-life crisis and snapped out of it with a whole new attitude.  Like Comet Holmes in 2007, it catapulted in brightness overnight in last October, blossoming from a 14th magnitude blip into a bright, expanding puffball briefly visible in ordinary binoculars. As expected, the comet soon faded. But on its return to obscurity,  X1 surprised again, re-brightening and growing a short tail. Now it’s humming along at 9th magnitude thank you very much. You’ll find it gliding across northern Ophiuchus not far from Lovejoy (more about that in a minute).

Very different appearance of C/2012 X1 LINEAR during outburst on Oct. 21, 2013. Credit: Ernesto Guido, Martino Nicolini & Nick Howes
Very different appearance of C/2012 X1 LINEAR during outburst on Oct. 21, 2013. Credit: Ernesto Guido, Martino Nicolini & Nick Howes

My binoculars won’t show the comet but a 6-inch telescope will do the trick. Overall weaker in appearance than Lovejoy, X1 LINEAR has a slightly larger, more diffuse coma,  brighter core and a short, faint tail pointing to the northwest. The comet will remain a fine target for smaller scopes through early March when it’s predicted to glow between magnitude 8 and 9.

Comets Lovejoy and X1 LINEAR will be closest together on the morning of Feb. 6 CST. Notice that they'll be in the company of numerous deep sky objects. Looks like a morning's worth of observing to me! Created with Chris Marriott's SkyMap software
Comets Lovejoy and X1 LINEAR will be closest together on the morning of Feb. 6 CST. A plethora of deep sky objects near them will make  for a complete morning’s worth of sky watching! Click to enlarge. Created with Chris Marriott’s SkyMap software

Looking at the maps, you’ll see that our two comets’ paths intersect. While they won’t overlap on the same morning, Lovejoy and X1 LINEAR will be in conjunction on Feb. 6 when they’ll be just 2 degrees apart. Get that camera ready! Guided telephoto and wide-field telescopes will be perfect for catching this unusual duet.

Before I sign off, don’t forget all the other good morning stuff: Mars hovers above Spica high in the south-southwestern sky, Saturn invites inspection in the southeast and Venus is back in view in the east-southeast 45 minutes before sunup. A delicate crescent moon shines near Venus on Jan. 28 and 29. Such riches.

Comet Tourism Flight Trades ISON For Lovejoy

When Comet ISON entered its zombie stage a few weeks ago, the effects were not only felt in the astronomical community, but also on astronomy tourists as the comet faded from the view of amateurs.

German company “Eclipse-Reisen” (Eclipse Travel) had to make a last-minute change in plans for a Dec. 8 flight for some 75 tourists planning to observe ISON, which morphed into a travelling dust blob after skimming too close to the sun in late November. Fortunately, Comet Lovejoy is still a strong astronomical object, providing an alternate thing to watch.

“Most of the passengers weren’t disappointed. They were more excited to see something new. Only a few journalists cancelled the flight. All photographers and experts fully understood the situation,” a statement from Air Partner to Universe Today said. (The spokespeople were German-speaking, requiring a translation by another party.)

Negative image taken Nov. 14 of Lovejoy's nucleus and dust fan. Credit: Dr. P. Clay Sherrod
Negative image taken Nov. 14 of Lovejoy’s nucleus and dust fan. Credit: Dr. P. Clay Sherrod

“Comet Lovejoy is no less spectacular and still very exciting like ISON and they were pleased to see it, actually. Although Lovejoy is less bright than ISON, it is weaker by four size classes, its tail is smaller and pale and Lovejoy flies farther past the Earth and the Sun.”

The company had to ask for permission to alter its flight path, and inform the passengers of the last-minute change, all in a few days, but officials added that the flight went off without a hitch.

You can read more information about the company (in German) on its website. In 2014, it plans to run a flight to observe auroras over Iceland, among others.

Virtual Star Party – November 24, 2013: Comets and More!

Hosts: Fraser Cain, Scott Lewis

Astronomers: Bill McLaughlin, David Dickinson, Tom Nathe, Mike Phillips

Viewing: M103, Cocoon Nebula, Comet Lovejoy, more to come!

We hold the Virtual Star Party every Sunday night as a live Google+ Hangout on Air. We begin the show when it gets dark on the West Coast. If you want to get a notification, make sure you circle the Virtual Star Party on Google+. You can watch on our YouTube channel or here on Universe Today.

Comet ISON Grows Wings; Comet Lovejoy, a Fountain

Wonderful photos of Comets ISON and Lovejoy with their swollen comas and developing tails  have appeared on these pages, but recently, amateur and professional astronomers have probed deeper to discover fascinating dust structures emanating from their very cores. Most comets possess a fuzzy, starlike pseudo-nucleus glowing near the center of the coma. Hidden within this minute luminous cocoon of haze and gas lies the true comet nucleus, a dark, icy body  that typically spans from a few to 10 kilometers wide. Comet ISON’s nucleus could be as large as several kilometers and hefty enough (we hope!) to survive its close call with the sun on Nov. 28.

Sketch using Photoshop of the inner region of Comet Lovejoy's coma showing the false nucleus and the curious dust fountain observed on Nov. 13 in a 15-inch (37-cm) telescope. Credit: Bob King. The dust fountain or plume captured on Nov. 12 next to the false nucleus deep within the coma of Comet Lovejoy. Credit: Luc Arnold
Sketch using Photoshop of the inner region of Comet Lovejoy’s coma showing the false nucleus and the curious dust fountain observed on Nov. 13 in a 15-inch (37-cm) telescope. Credit: Bob King. At right the same plume photographed on Nov. 12 with north up and east to the left. Credit: Luc Arnold

Last Wednesday morning Nov. 13 when calm air allowed a sharp view inside Comet Lovejoy’s large, 15-arc-minute-wide coma I noticed something odd about the false nucleus at low magnification, so I upped the power to 287x for a closer look. Extending from the fuzzy core in the sunward direction was a small cone or fountain-shaped structure of denser, brighter dust shaped like a miniature comet. It stretched eastward from the center and wrapped slightly to the south. Usually it’s harder than heck to see any details within the fuzzy, low-contrast environment of a comet’s coma unless that comet is close to Earth and actively spewing dust and ice. Lovejoy scored on both.

Negative image taken Nov. 14 of Lovejoy's nucleus and dust fan. Credit: Dr. P. Clay Sherrod
Negative image taken Nov. 14 of Lovejoy’s nucleus and dust fan. North up, west to the right. Credit: Dr. P. Clay Sherrod

By good fortune, Dr. P. Clay Sherrod of the Arkansas Sky Observatories, USA, and Luc Arnold of Saint-Michel-l’Observatoire, France, shared images they’d made at high magnification of the identical feature right at the same time as my own observation. There’s no doubt that what we saw was a jet or combined jets of dust and vapor blasting from Lovejoy’s true nucleus. Jets are linear or fan-shaped features and carry ice, dust and even snowballs from inside the nucleus out into space. They typically form where freshly-exposed ice from breaks or fissures in the comet’s crust vaporizes in the sun’s heat.

What I wouldn’t give to see one up close. Wait – we can. Take a look at the photo of Comet 103P/Hartley made during NASA’s EPOXI flyby mission in November 2010. Notice that most of Hartley’s crust appears intact with the jets being the main contributors to the dust and gas that form the coma and tail.

Multiple jets were actively spewing ice and dust when NASA's EPOXI mission zoomed by Comet Hartley 2  in November 2010. Credit: NASA
Multiple jets were actively spewing ice and dust when NASA’s EPOXI mission zoomed by Comet Hartley 2 in November 2010. The fuzzy spots are balls of fluffy snowballs measuring between 1 inch and 1 foot across. Credit: NASA

Spotting a jet usually requires good seeing (low atmospheric turbulence) and high magnification. They’re low-contrast features but worth searching for in any bright comet. Jets often point toward the sun for good reason – the sunward side of the comet is where the heating is happening. Activity dies back as the comet rotates to face away from the sun during the night and early morning hours. By studying the material streaming away from a comet via jets, astronomers can determine the rotation period of the nucleus.

Nightly images of Comet Hale-Bopp made March 24-30, 1997 by Brad D. Wallis of the Cassini imaging team at JPL. The photos were assembled into this animation by Sky & Telescope
Nightly images of Comet Hale-Bopp’s rotating nucleus and spiraling jet made March 24-30, 1997 by Brad D. Wallis of JPL. The photos were assembled into this animation by Sky & Telescope

Sometimes material sprayed by jets expands into a curved parabolic hood within the coma. This may explain the wing-shaped structures poking out from Comet ISON’s coma seen in recent photos. Possibly the Nov. 13-14 outburst released a great deal of fresh dust that’s now being pushed back toward the tail by the ever-increasing pressure of sunlight as the comet approaches perihelion.

The inner coma of Comet Hale-Bopp developed a striking series of hoods in March 1997 when a dust jet spewed material night after night from the comet’s rotating nucleus. The animation captures garden sprinkler effect beautifully. Since the nucleus spun around every 11 hours 46 minutes, multiple spiraling waves passed through the coma in the sunward direction. To the delight of amateur astronomers at the time, they were plainly visible through the telescope.

Processed images showing a possible jet next to Comet ISON' nucleus as well as the new wing-like coma structures on Nov. 17, 2013.  The jet's position angle or PA is 150 degrees or southeast of the nucleus. Credit: Denis Buczynski and Nick James
Processed images showing a possible jet extending southeast (PA 150 degrees) of Comet ISON’s nucleus as well as the new wing-like hoods on Nov. 17, 2013.  Credit: Denis Buczynski and Nick James of the BAA

When examining a comet, I start at low magnification and note coma shape, compactness and color as well as tail form and length and details like the presence of streamers or knots. Then I crank up the power and carefully study the area around the nucleus. Surprises may await your careful gaze. If Comet ISON does break up, the first sign of it happening might be an elongation or stretching of the false nucleus. If it’s no longer a small, star-like disk or if you notice a fainter, second nucleus tailward of the main, the comet’s days may be numbered.

Symmetrical "wings" photographed branching from Comet ISON's coma on Nov. 15. At right, the photo has been specially processed to show the structure more clearly. Credit: Erik Bryssinck
Another view of the symmetrical “wings” photographed branching from Comet ISON’s coma on Nov. 15. At right, the photo has been specially processed to show the structure more clearly. Credit: Erik Bryssinck