ISON Archives

September 16, 2016September 16, 2016 by Bob King

Hubble Captures The Sharpest Image Of A Disintegrating Comet Ever

Comet 332P breakup. Credit: NASA, ESA, and D. Jewitt (UCLA)

This NASA Hubble Space Telescope image reveals the ancient Comet 332P/Ikeya-Murakami disintegrating as it approaches the sun. The observations represent one of the sharpest views of an icy comet breaking apart. The comet debris consists of a cluster of building-size chunks near the center of the image. They form a 3,000-mile-long trail, larger than the width of the continental U.S. The fragments are drifting away from the comet at a leisurely pace, roughly the walking speed of an adult. The main nucleus of Comet 332P is the bright object at lower left. It measures 1,600 feet across, about the length of five football fields. Credit: NASA, ESA, and D. Jewitt (UCLA) — This Hubble Space Telescope image reveals the ancient Comet 332P/Ikeya-Murakami disintegrating as it approaches the sun. The comet debris consists of a cluster of building-size chunks near the center of the image. They form a trail larger than the width of the continental U.S. The fragments are drifting away from the comet at a leisurely pace of just a few miles an hour. The main nucleus of Comet 332P is the bright object at lower left. It measures 1,600 feet across, about the length of five football fields. Credit: NASA, ESA, and D. Jewitt (UCLA)

Breaking up isn’t hard to do if you’re a comet. They’re fragile creatures subject to splitting, cracking and vaporizing when heated by the Sun and yanked on by its powerful gravitational pull.

Recently, the Hubble Space Telescope captured one of the sharpest, most detailed observations of a comet breaking apart, which occurred 67 million miles from Earth. In a series of images taken over a three-day span in January 2016, Hubble revealed 25 building-size blocks made of a mixture of ice and dust that are drifting away from the main nucleus of the periodic comet 332P/Ikeya-Murakami at a leisurely pace, about the walking speed of an adult.

332P on UT 2016 January 26, 27 and 28, showing fragments measured in this work. The images are displayed consecutively as an animated gif in order to show the motion of the fragments relative to the parent nucleus (visible as the bright object to the lower left). The actual motions are very slow, of order 1 m/s, and show a fan-like divergence from the parent. Notice that some of the fragments also change in brightness and even shape from day to day. We think this is due to continuing outgassing, rotation and breakup of the fragments. — This animation shows the movement of individual comet fragments relative to the parent nucleus, the bright object at lower left, on January 26, 27 and 28 UT. The true motions are very slow, on the order of several miles an hour, and show a fan-like divergence from the parent. Look closely and you’ll see that some of the fragments change in brightness and even shape from day to day. Researcher David Jewitt thinks this is due to continuing outgassing, rotation and breakup of the fragments. Credit: NASA, ESA, and D. Jewitt (UCLA)

The observations suggest that the comet may be spinning so fast that material is ejected from its surface. The resulting debris is now scattered along a 3,000-mile-long trail, larger than the width of the continental U.S. Much the same happens with small asteroids, when sunlight absorbed unequally across an asteroid’s surface spins up its rotation rate, either causing it to fall apart or fling hunks of itself into space.

Being made of loosely bound frothy ice, comets may be even more volatile compared to the dense rocky composition of many asteroids. The research team suggests that sunlight heated up the comet, causing jets of gas and dust to erupt from its surface. We see this all the time in comets in dramatic images taken by the Rosetta spacecraft of Comet 67P/Churyumov-Gerasimenko. Because the nucleus is so small, these jets act like rocket engines, spinning up the comet’s rotation. The faster spin rate loosened chunks of material, which are drifting off into space.

Comet 168P-Hergenrother was imaged by the Gemini telescope on Nov. 2, 2012 at about 6 a.m. UTC. Image Credit: NASA/JPL-Caltech/Gemini — Comet 168P/Hergenrother was photographed by the Gemini telescope on Nov. 2, 2012 and shows three fragments that broke away from the nucleus streaming from the coma down the tail. Credit: NASA/JPL-Caltech/Gemini

“We know that comets sometimes disintegrate, but we don’t know much about why or how they come apart,” explained lead researcher David Jewitt of the University of California at Los Angeles. “The trouble is that it happens quickly and without warning, and so we don’t have much chance to get useful data. With Hubble’s fantastic resolution, not only do we see really tiny, faint bits of the comet, but we can watch them change from day to day. And that has allowed us to make the best measurements ever obtained on such an object.”

In the animation you can see the comet splinters brighten and fade as icy patches on their surfaces rotate in and out of sunlight. Their shapes even change! Being made of ice and crumbly as a peanut butter cookie, they continue to break apart to spawn a host of smaller cometary bits. The icy relics comprise about 4% of the parent comet and range in size from roughly 65 feet wide to 200 feet wide (20-60 meters). They are moving away from each other at a few miles per hour.

Crack on 67P - a sign of a coming breakup? — The European Space Agency’s Rosetta probe photographed this big crack in the neck region of the double-lobed comer 67P. It’s several feet wide and about 700 feet long. Could it be an indicator that the comet will break into two in the future? Credit: ESA/Rosetta

Comet 332P was slightly beyond the orbit of Mars when Hubble spotted the breakup. The surviving bright nucleus completes a rotation every 2-4 hours, about four times as fast as Comet 67P/Churyumov-Gerasimenko (a.k.a. “Rosetta’s Comet”). Standing on its surface you’d see the sun rise and set in about an hour, akin to how frequently astronauts aboard the International Space Station see sunsets and sunrises orbiting at over 17,000 mph.

Don’t jump for joy though. Since the comet’s just 1,600 feet (488 meters) across, its gravitational powers are too meek to allow visitors the freedom of hopping about lest they find themselves hovering helplessly in space above the icy nucleus.

This illustration shows one possible explanation for the disintegration of asteroid P/2013 R3. It is likely that over the past 4.5 billion years the asteroid was fractured by collisions with other asteroids. The effects of sunlight will have caused the asteroid to slowly increase its rotation rate until the loosely bound fragments drifted apart due to centrifugal forces. Dust drifting off the pieces makes the comet-looking tails. This process may be common for small bodies in the asteroid belt. — This illustration shows one possible explanation for the disintegration of asteroids and comets. The effects of sunlight can cause an asteroid to slowly increase its rotation rate until the loosely bound fragments drift apart due to centrifugal forces. In the case of comets, jets of vaporizing ice have a rocket-like effect that can spin up a nucleus to speeds fast enough for the comet to eject pieces of itself. Credit: NASA, ESA, D. Jewitt (UCLA), and A. Feild (STScI)

Comet 332P was discovered in November 2010, after it surged in brightness and was spotted by two Japanese amateur astronomers, Kaoru Ikeya and Shigeki Murakami. Based on the Hubble data, the team calculated that the comet probably began shedding material between October and December 2015. From the rapid changes seen in the shards over the three days captured in the animation, they probably won’t be around for long.

Spectacular breakup of Comet 73P in 2006

More changes may be in the works. Hubble’s sharp vision also spied a chunk of material close to the comet, which may be the first salvo of another outburst. The remnant from still another flare-up, which may have occurred in 2012, is also visible. The fragment may be as large as Comet 332P, suggesting the comet split in two.

“In the past, astronomers thought that comets die when they are warmed by sunlight, causing their ices to simply vaporize away,” Jewitt said. “Either nothing would be left over or there would be a dead hulk of material where an active comet used to be. But it’s starting to look like fragmentation may be more important. In Comet 332P we may be seeing a comet fragmenting itself into oblivion.”

During its closest approach to the Sun on November 28, 2013, Comet ISON’s nucleus broke apart and soon vaporized away, leaving little more than a ghostly head and fading tail.

Astronomers using the Hubble and other telescopes have seen breakups before, most notably in April 2006 when 73P/Schwassmann-Wachmann 3, which crumbled into more than 60 pieces. Unlike 332P, the comet wasn’t observed long enough to track the evolution of the fragments, but the images are spectacular!

The researchers estimate that Comet 332P contains enough mass to endure another 25 outbursts. “If the comet has an episode every six years, the equivalent of one orbit around the sun, then it will be gone in 150 years,” Jewitt said. “It’s the blink of an eye, astronomically speaking. The trip to the inner Solar System has doomed it.”

332P/Ikeya-Murakami hails from the Kuiper Belt, a vast swarm of icy asteroids and comets beyond Neptune. Leftover building blocks from early Solar System and stuck in a deep freeze in the Kuiper Belt, you’d think they’d be left alone to live their solitary, chilly lives but no. After nearly 4.5 billion years in this icy deep freeze, chaotic gravitational perturbations from Neptune kicked Comet 332P out of the Kuiper Belt.

As the comet traveled across the solar system, it was deflected by the planets, like a ball bouncing around in a pinball machine, until Jupiter’s gravity set its current orbit. Jewitt estimates that a comet from the Kuiper Belt gets tossed into the inner solar system every 40 to 100 years.

I wish I could tell you to grab your scope for a look, but 332P is currently fainter than 15th magnitude and located in Libra low in the southwestern sky at nightfall. Hopefully, we’ll see more images in the coming weeks and months as Jewitt and the team continue to follow the evolution of its icy scraps.

December 1, 2015December 23, 2015 by David Dickinson

The Solar Heliospheric Observatory at 20

Flashback to 1995: Clinton was in the White House, Star Trek Voyager premiered, we all carried pagers in the pre-mobile phone era, and Windows 95 and the Internet itself was shiny and new to most of us. It was also on this day in late 1995 when our premier eyes on the Sun—The SOlar Heliospheric Observatory (SOHO)—was launched. A joint mission between NASA and the European Space Agency, SOHO lit up the pre-dawn sky over the Florida Space Coast as it headed space-ward atop an Atlas IIAS rocket at 3:08 AM EST from launch complex 39B at Cape Canaveral Air Force Station.

Envisioning SOHO

There aren’t a whole lot of 20^th century spacecraft still in operation; SOHO joins the ranks of Hubble and the twin Voyager spacecraft as platforms from another era that have long exceeded their operational lives. Seriously, think back to what YOU were doing in 1995, and what sort of technology graced your desktop. Heck, just thinking of how many iterations of mobile phones spanned the last 20 years is a bit mind-bending. A generation of solar astronomers have grown up with SOHO, and the space-based observatory has consistently came through for researchers and scientists, delivering more bang for the buck.

“SOHO has been truly extraordinary and revolutionary in countless ways,” says astrophysicist Karl Battams at the Naval Research Laboratory in Washington D.C. “SOHO has completely changed our way of thinking about the Sun, solar active regions, eruptive events, and so much more. I honestly can’t think of a more broadly influential space mission than SOHO.”

SOHO has monitored the Sun now for the complete solar cycle #23 and well into the ongoing solar cycle #24. SOHO is a veritable Swiss Army Knife for solar astrophysics, not only monitoring the Sun across optical and ultraviolet wavelengths, but also employing the Michelson Doppler Imager to record magnetogram data and the Large Angle Spectrometric Coronograph (LASCO) able to create an artificial solar eclipse and monitor the pearly white corona of the Sun.

SOHO observes the Sun from its perch one million miles sunward located at the L1 Sun-Earth point. It actually circles this point in space in what is known as a lissajous, or ‘halo’ orbit.

SOHO has revolutionized solar physics and the way we perceive our host star. We nearly lost SOHO early on in its career in 1998, when gyroscope failures caused the spacecraft to lose a lock on the Sun, sending it into a lazy one revolution per minute spin. Quick thinking by engineers led to SOHO using its reaction wheels as a virtual gyroscope, the first spacecraft to do so. SOHO has used this ad hoc method to point sunward ever since. SOHO was also on hand to document the 2003 Halloween flares, the demise of comet ISON on U.S. Thanksgiving Day 2013, and the deep and strangely profound solar minimum that marked the transition from solar cycle 23 to 24.

What was your favorite SOHO moment?

Massive sunspot — A massive sunspot witnessed by SOHO in 2000, compared to the Earth.

SOHO is also a champion comet hunter, recently topping an amazing 3000 comets and counting. Though it wasn’t designed to hunt for sungrazers, SOHO routinely sees ’em via its LASCO C2 and C3 cameras, as well as planets and background stars near the Sun. The effort to hunt for sungrazing comets crossing the field of view of SOHO’s LASCO C3 and C2 cameras represents one of the earliest crowd-sourced efforts to do volunteer science online. SOHO has discovered enough comets to characterize and classify the Kreutz family of sungrazers, and much of this effort is volunteer-based. SOHO grew up with the internet, and the images and data made publicly available are an invaluable resource that we now often take for granted.

NASA/ESA has extended SOHO’s current mission out to the end of 2016. With any luck, SOHO will complete solar cycle 24, and take us into cycle 25 to boot.

“Right now, it (SOHO) is operating in a minimally funded mode, with the bulk of its telemetry dedicated solely to the LASCO coronagraph,” Battams told Universe Today. “Many of its instruments have now been superseded by instruments on other missions. As of today it remains healthy, and I think that’s a testament to the amazing collaboration between ESA and NASA. Together, they’ve kept a spacecraft designed for a two-year mission operating for twenty years.”

Today, missions such as the Solar Dynamics Observatory, Hinode, and Proba-2 have joined SOHO in watching the Sun around the clock. The solar occulting disk capabilities of SOHO’s LASCO C2 and C3 camera remains unique, though ESA’s Proba-3 mission launching in 2018 will feature a free-flying solar occulting disk.

Happy 20^th SOHO… you’ve taught us lots about our often tempestuous host star.

-It’s also not too late to vote for your favorite SOHO image.

September 10, 2015December 23, 2015 by David Dickinson

SOHO Nears 3,000 Comet Discoveries

A fine sungrazer nears its doom as seen via SOHOs LASCO C2 camera. Image credit: NASA/ESA/SOHO/NRLSungrazers

It’s a discovery that could come any day now.

The Solar Heliospheric Observatory spacecraft known as SOHO is set to cross the 3,000 comet discovery threshold this month. Launched atop an Atlas II rocket on December 2^nd, 1995, SOHO is a joint NASA/ESA mission, and has observed the Sun now for almost 20 years from the sunward L1 lagrange point. That fact is amazing enough, as SOHO has already followed the goings on of our tempestuous host star for nearly two full solar cycles.

And though SOHO wasn’t initially designed as a comet hunter extraordinaire, it has gone on to discover far more comets than anyone—human or robotic.

soho_photo7 — SOHO on Earth. Image credit: NASA/ESA/SOHO

The U.S. Naval Research Laboratory’s (NRL) sungrazer website lists the discovery count as 2,987 as of July 31, 2015, with more comets awaiting verification daily. “In the past, SOHO has often discovered as many as four or five comets in a single day,” Karl Battams, a solar scientist at the NRL told Universe Today. “Suffice to say, it really could be any day now, given how close we are to 3,000! I actually expected it to be a month ago, so I’m surprised it’s dragging out like this. Predicting comets is fraught with uncertainty!”

Part of what gives SOHO an edge is its LASCO (the Large Angle and Spectrometric Coronagraph) C2 and C3 coronagraphs. With a field of view about 15 degrees wide, the C3 imager monitors the faint corona of the Sun, while blocking its dazzling disk. The corona is the pearly white outer atmosphere of the Sun, and is about half as bright as a Full Moon. On Earth, we only see the corona briefly during a total solar eclipse. SOHO routinely sees sungrazing comets ‘photobomb’ the view of its LASCO C3 camera, sometimes to the tune of more than 200 a year.

Comet NEAT makes its way through the field of view of SOHO's LASCO C2 camera in 2003. Image credit: NASA/ESA/NRL/Sungrazers — Comet NEAT makes its way through the field of view of SOHO’s LASCO C2 camera in 2003. Image credit: NASA/ESA/NRL/Sungrazers

SOHO has rewritten the history of sungrazers. How far we’ve come: flashback to 1979, and less than a dozen sungrazers were known, one being the famous Comet Ikeya-Seki in 1965. Early space-based platforms such as Solwind and SMM sported early coronagraphs, and paved the way for SOHO. Think about that for a moment; a vast majority of the cometary population of the solar system was simply sliding by, unobserved from the ground. And this was only a generation ago.

Most of what SOHO sees are what’s termed as Kreutz group sungrazers. First theorized by astronomer Heinrich Kreutz in 1888, SOHO has given researchers the ability to classify and characterize the orbits of these doomed comets. These sungrazers nearly always incinerate during their perihelion passage. C/2011 W3 Lovejoy was a famous exception, which passed about 140,000 kilometers from the surface of the Sun on December 16^th, 2011 and went on to become a fine southern hemisphere comet.

“We knew little of the Kreutz population, other than that it seemed there were ‘a few’ objects on the Kreutz path,” Battams said. “I would say that probably when the Sungrazer Project was launched in late 2000 was the point at which the team realized that this was something more than just seeing an occasional comet.”

The typical track of a Kreutz-group comet. Click here for the full diagram of C2/C3 tracks throughout the year. Image Credit: NASA/ESA/SOHO

Kreutz comets also have seasons and predictable directions of approach along the ecliptic as seen from SOHO’s point of view. Some periodic comets, such as 96P Machholz, — which orbits the Sun once every six years — have become old friends. To date, SOHO has observed 96P Machholz four times.

Upping the Comet Hunting Game

But here’s the amazing second half of the tale. Legions of dedicated amateurs make these discoveries, patiently combing over daily images sent back by SOHO. In many ways, SOHO has grown up with the rise of the internet. Think about it: what was your internet surfing experience like way back in 1995? Karl Battams at NRL relays these discoveries to the Central Bureau for Astronomical Telegrams, the clearing house for potential comet discoveries. Founded in 1882 and based at Harvard College Observatory since 1965, CBAT actually received its last ‘telegram’ announcing the possible discovery that would become Comet Hale-Bopp in 1995.

The rise of automated surveys and satellites such as SOHO has definitely upped the game. To date, the all-time human champ amongst comet hunters is Robert H. McNaught, with the discovery of 44 long-period and 26 short-period comets.

And I think we can all remember where we were on U.S. Thanksgiving Day 2013, as SOHO gave us a front row seat to the demise of Comet ISON. It’s been a roller coaster ride for sure, and it’s hard to imagine a time now when we didn’t have SOHO as a daily resource. Heck, it’s just fun to watch planets transit the field of view of SOHO, as they move from the dawn to dusk sky and back again.

Looking at the "SOHO Bump" and the rise of automated comet hunters in the early 21st century. Image credit: Dave Dickinson — Looking at the “SOHO Bump” and the rise of automated comet hunters in the early 21st century. Image credit: Dave Dickinson

Comet hunting via SOHO is fun and easy to do, though yes, there are lots of eyeballs out there looking, so you have some pretty dedicated competition. Patience is key, and there’s also a dedicated message board describing the latest discoveries and known objects entering the field of view that have already been identified.

“What’s the future of SOHO? “December is SOHO’s 20^th anniversary, so that’s another milestone,” Battams said. “Beyond that, who knows? Engineers designed SOHO to operate for two years, and with no intention of comet discovery; it has lasted 20 years and re-written the history books for comets. It remains the only coronagraph we have along the Sun-Earth line, so for space weather forecasting it remains a unique and valuable asset.”

Congrats, and be sure to follow Karl Battam’s @SungrazerComets account on Twitter… number 3,000 could be discovered any day now!

August 12, 2014December 23, 2015 by Elizabeth Howell

Some Of Comet ISON’s Organic Materials Arose In An Unexpected Place

Comet ISON was one of the two comets studied by scientists using the Atacama Large Millimeter/submillimeter Array (ALMA). The diagram shows where it was located in the solar system at the time of observations. 3-D images of its coma (atmosphere) revealed organic compounds. Credit: B. Saxton (NRAO/AUI/NSF); NASA/ESA Hubble; M. Cordiner, NASA, et al.

While Comet ISON’s breakup around Thanksgiving last year disappointed many amateur observers, its flight through the inner solar system beforehand showed scientists something neat: it was carrying organic materials with it.

A group examined the molecules surrounding the comet in its coma (atmosphere) and, along with observations of Comet Lemmon, created a 3-D model that you can see above. Among other results, this revealed the presence of formaldehyde and HNC (hydrogen, nitrogen and carbon). The formaldehyde was expected, but the spot where HNC was found came as a surprise.

Scientists used to think that HNC is produced from the nucleus, but the research revealed that it actually happens when larger molecules or organic dust breaks down in the coma.

“Understanding organic dust is important, because such materials are more resistant to destruction during atmospheric entry, and some could have been delivered intact to early Earth, thereby fueling the emergence of life,” stated Michael Mumma, a co-author on the study who is director of the Goddard Center for Astrobiology. “These observations open a new window on this poorly known component of cometary organics.”

Observation were made possible using the powerful Atacama Large Millimeter/submillimeter Array (ALMA). The array of 66 radio telescopes in Chile allows astronomers to map molecules and peer past dust clouds in star systems under formation, among other things. ALMA was completed last year and is the largest telescope of its type in the world.

The array’s resolution allowed scientists to probe for these molecules in moderately bright comets, which is also new. Previously, these types of studies were limited to “blockbuster” visitors such as Comet Hale-Bopp in the 1990s, NASA sated.

The study, which was led by the Goddard Center for Astrobiology’s Martin Cordiner at NASA’s Goddard Space Flight Center, was published in Astrophysical Journal Letters. The research is also available in preprint version on Arxiv.

Source: NASA

July 17, 2014December 23, 2015 by Elizabeth Howell

ISON Stopped Making Dust Just Before It Passed By The Sun And Disintegrated

Bright, brighter, brightest: these views of Comet ISON after its closest approach to the sun Nov. 28 show that a small part of the nucleus may have survived the comet's close encounter with the sun. Images from the Solar and Heliospheric Observatory. Credit: ESA/NASA/SOHO/GSFC

Last year’s Thanksgiving adventure for astronomers happened when Comet ISON passed within 1.2 million kilometres (750,000 miles) of the Sun. While many people were hoping the comet would stick around and produce a good show, the comet disintegrated despite a brief flare-up shortly after passing perihelion.

Scientists have just modelled the production of dust on the comet and concluded there was a “violent outburst” that happened 8.5 hours before closest approach, when the comet spewed out 11,500 tonnes (12,765 tons) of material.

“It is most likely that the final break-up of the nucleus triggered this eruption, abruptly releasing gas and dust trapped inside the nucleus,” stated Werner Curdt from the Max Planck Institute of Solar System Research, who was the lead researcher on the project. “Within a few hours the dust production stopped completely.”

Because the last few parts of the comet’s encounter were obscured by an occulting disk on the Large Angle and Spectrometric Coronagraph on the Solar and Heliospheric Observatory (SOHO), astronomers decided to model the encounter based on other data they gathered before and after.

Comet ISON captured in an image from the Solar and Heliospheric Observatory (SOHO)'s Solar Ultraviolet Measurements of Emitted Radiation (SUMER) instrument. Credit: MPS — Comet ISON captured in an image from the Solar and Heliospheric Observatory (SOHO)’s Solar Ultraviolet Measurements of Emitted Radiation (SUMER) instrument. Credit: MPS

They did have one source of data, which was another instrument called the Solar Ultraviolet Measurements of Emitted Radiation (SUMER). It’s usually used to investigate plasma activity on the sun and not faint comets, but the scientists felt it could be repurposed. T

hey switched modes on the instrument and captured the tail in far ultraviolet light, light “emitted from the solar disc and reflected by the dust particles into space,” the European Space Agency stated.

Then they compared what they saw with computer simulations, coming up with the dust estimations.

The paper is available in the journal Astronomy & Astrophysics and also in preprint version on Arxiv.

Source: European Space Agency

June 17, 2014December 23, 2015 by David Dickinson

Asteroid-Turned-Comet 2013 UQ4 Catalina Brightens: How to See it This Summer

Though ISON may have fizzled in early 2014, we’ve certainly had a bevy of binocular comets to track this year. Thus far in 2014, we’ve had comets R1 Lovejoy, K1 PanSTARRS, and E2 Jacques reach binocular visibility. Now, and asteroid-turned-comet is set to put on a fine show this summer for northern hemisphere observers.

Veteran stargazer and Universe Today contributor Bob King told the tale last month of how the asteroid formerly known as 2013 UQ4 became comet 2013 UQ4 Catalina. Discovered last year on October 23^rd 2013 during the routine Catalina Sky Survey searching for Near Earth Objects based outside of Tucson Arizona, this object was of little interest until early this year.

As it rounded the Sun, astronomers recovered the asteroid and discovered that it had begun to sprout a fuzzy coma, a very un-asteroid-like thing to do. Then, on May 7^th, Taras Prystavski and Artyom Novichonok — of Comet ISON fame — conducted observations of 2013 UQ4 and concluded that it was indeed an active comet.

Hovering around +13^th magnitude last month, newly rechristened 2013 UQ4 Catalina was a southern hemisphere object visible only from larger backyard telescopes. That should change, however, in the coming weeks if activity from this comet holds up.

Light curve — The light curve of UQ4 Catalina with current observations (dots) noted. Credit: Seiichi Yoshida/Aerith.net.

2013 UQ4 belongs to a class of objects known as damocloids. These asteroids are named after the prototype for the class 5335 Damocles and are characterized as long-period bodies in retrograde and highly eccentric orbits. These are thought to be inactive varieties of comet nuclei, and other asteroids in the damocloid series such as C/2001 OG 108 (LONEOS) and C/2002 VQ94 (LINEAR) also turned out to be comets. Damocloids also exhibit the same orbital characteristics of that most famous inner solar system visitor of them all; Halley’s Comet.

The path of Comet 9PM 30deg north — The path of Comet UQ4 Catalina looking towards the NE at 9PM local in early July from latitude 30 degrees north. Credit: Stellarium.

The good news is, 2013 UQ4 Catalina is brightening on schedule and should be a binocular object greater than +10^th magnitude by the end of June. Recent observations, including those made by Alan Hale (of comet Hale-Bopp fame) place the comet at magnitude +11.9 with a bullet. The comet is currently placed high in the east in the constellation Pisces at dawn, and will soon speed northward and vault across the sky as it crosses the ecliptic plane this week. In fact, comet 2013 UQ4 Catalina reaches perihelion on July 6th only four days before its closest approach to the Earth at 47 million kilometres distant, when it may well reach a peak magnitude of +7. At that point, the comet will have an apparent motion of about 7 degrees a day — that’s the span of a Full Moon once every 1 hour and 42 minutes — as it rises in the constellation Cepheus to the northeast at dusk in early July. A fine placement, indeed. And speaking of the Moon, our natural satellite reaches New phase later this month on June 27^th, another good reason to begin searching for 2013 UQ4 Catalina now.

Here’s a list of notable events to watch out for and aid you in your quest as comet 2013 UQ4 Catalina crosses the summer sky:

June 16^th: The comet crosses north of the ecliptic plane.

June 20^th: The waning crescent Moon passes 3 degrees from the comet.

starry nite — The celestial path of the comet from June 16th to July 15th… Credit: Starry Night Education software.

June 29^th: Crosses into the constellation of Andromeda.

July 1^st: Passes less than one degree from the +2^nd magnitude star Alpheratz.

July 2^nd: Crosses briefly into the constellation Pegasus before passing back into Andromeda.

July 6^th: The comet reaches perihelion or its closest point to the Sun at 1.081 A.U.s distant.

July 7^th: Crosses into the constellation of Lacerta and passes the deep sky objects NGCs 7296, 7245, 7226.

July 8^th: Crosses into the constellation Cepheus and across the galactic plane.

July 9^th: Passes a degree from the Elephant Trunk open star cluster.

July 10^th: Passes less than one degree from the stars Eta (magnitude +3.4) and Theta (magnitude +4.2) Cephei.

July 10^th: Passes 2 degrees from the +7.8 magnitude Open Cluster NGC 6939.

July 10^th: Passes closest to Earth at 0.309 A.U.s or 47 million kilometres distant.

July 11^th: Crosses into the constellation Draco.

July 11^th: Reaches its most northerly declination of 64 degrees.

July 12^th: Photo op: the comet passes 3 degrees from the Cat’s Eye Nebula.

July 15th- August 20th — … and the path of the comet from July 15th to August 20th. Credit: Starry Night.

July 17^th: The comet passes into the astronomical constellation of Boötes.

July 31^st: Passes just 2 degrees from globular cluster NGC5466 (+9^th magnitude) and 6 degrees from the famous globular cluster Messier 3.

From there on out, the comet drops below naked eye visibility and heads back out in its 470 year orbit around the Sun. Be sure to check out comet 2013 UQ4 Catalina this summer… what will the Earth be like next time it passes by in 2484 A.D.?

April 14, 2014December 23, 2015 by Bob King

Comet ISON Photo Contest Winners Rock the House!

"Comet ISON" -- People's Choice award winner: Eric Cardoso, Setúbal, Portugal, Credit: Eric Cardoso

Comet ISON’s gone but positively not forgotten. The National Science Foundation today shared the results of their Comet ISON Photography Contest. You’ll recognize many of the names because so many of their photos have graced stories written for Universe Today.

Come take a look back at the high points of one of the most highly anticipated and studied comets of all time. Click each photo for a full-sized view. Congratulations to all the winners!

"Broom Star" -- 1st place in the Through the Telescope category: Damian Peach, Hampshire, U.K., Credit: Damian Peach — “Broom Star” — 1st place in the Through the Scope category: Damian Peach, Hampshire, U.K., Credit: Damian Peach

"C/2012 S1 ISON" -- 2nd place Through the Scope: Gerald Rhemann, Vienna, Austria. Credit: Gerald Rhemann — “C/2012 S1 ISON” — 2nd place Through the Scope: Gerald Rhemann, Vienna, Austria. Credit: Gerald Rhemann

"Comet ISON over Pokhara City, Nepal" -- 1st place Cameras and Tripods: Atish Aman, Delhi, India, Credit: Atish Aman — “Comet ISON over Pokhara City, Nepal” — 1st place Cameras and Tripods category: Atish Aman, Delhi, India. Credit: Atish Aman

"Comet ISON, Port Medway, Nova Scotia" -- 2nd place Cameras and Tripods: Barry Burgess, Nova Scotia, Canada. Credit: Barry Burgess — “Comet ISON, Port Medway, Nova Scotia” — 2nd place Cameras and Tripods category: Barry Burgess, Nova Scotia, Canada. Credit: Barry Burgess

"Comet ISON Gossamer Tail & Disconnection Event" -- 1st place Piggyback Cameras: John Chumack, Ohio, USA. Credit: John Chumack — “Comet ISON Gossamer Tail & Disconnection Event” — 1st place Piggyback Cameras category: John Chumack, Ohio, USA. Credit: John Chumack

"Mercury and ISON" 2nd place Piggyback Cameras: Gaeul Song, Korea. Credit: Gaeul Song — “Mercury and ISON” — 2nd place Piggyback Cameras: Gaeul Song, Korea. Credit: Gaeul Song

February 21, 2014April 26, 2016 by Elizabeth Howell

Comet ISON Hosted A Rare Kind Of Nitrogen, Hinting At Reservoirs In Young Solar System

Spectacular photo of Comet ISON taken Nov. 15 from Charleston, Rhode Island, USA showing the recent outburst. Click to enlarge. Credit: Scott MacNeill

Comet ISON — that bright comet last year that broke up around Thanksgiving weekend — included two forms of nitrogen in its icy body, according to newly released observations from the Subaru Telescope.

Of the two types found, the discovery of isotope 15NH2 was the first time it’s ever been seen in a comet. Further, the observations from the Japanese team of astronomers show “there were two distinct reservoirs of nitrogen [in] the massive, dense cloud … from which our Solar System may have formed and evolved,” stated the National Astronomical Observatory of Japan.

Besides being pretty objects to look at, comets are considered valuable astronomical objects because they’re a sort of time capsule of conditions early in the universe. The “fresh” comets are believed to come from a vast area of icy bodies called the Oort Cloud, a spot that has been relatively untouched since the solar system formed about 4.6 billion years ago. Spying elements inside of comets can give clues as to what was present in our neighborhood when the sun and planets were just coming to be.

“Ammonia (NH3) is a particularly important molecule, because it is the most abundant nitrogen-bearing volatile (a substance that vaporizes) in cometary ice and one of the simplest molecules in an amino group (–NH2) closely related to life. This means that these different forms of nitrogen could link the components of interstellar space to life on Earth as we know it,” NAOJ stated.

You can read more details about the finding at the NAOJ website, or in Astrophysical Journal Letters.

January 29, 2014December 23, 2015 by David Dickinson

NEOWISE Spots Mars-Crossing Comet

NASA's NEOWISE Mission takes aim at Comet A1 Siding Spring on January 16th, 2014 when the comet was 571 million kilometres distant. Credit: NASA/JPL-Caltech

One of the big ticket astronomical events of 2014 will be the close passage of Comet C/2013 A1 Siding Spring past the planet Mars in October 2014. Discovered just over a year ago from the Australian-based Siding Spring Observatory, this comet generated a surge of excitement in the astronomical community when it was discovered that it was going to pass very close to the planet Mars in late 2014.

Now, a fleet of spacecraft are poised to study the comet in unprecedented detail. Some of the first space-based observations of the comet have been conducted by NASA’s Hubble Space Telescope and the recently reactivated NEOWISE mission. And although the comet may not look like much yet in the infrared eyes of NEOWISE, its estimated 4 kilometre in diameter nucleus is already active and shedding about 100 kilograms of dust per second.

And although an impact has been since ruled out, it’s that dust that may present a hazard for Mars orbiting spacecraft, as well as a unique scientific observing opportunity.

“Our plans for using spacecraft at Mars to observe Comet A1 Siding Spring will be coordinated with plans for how the orbiters will duck and cover, if we need to do so that,” said NASA/JPL Mars Exploration Program chief scientist Rich Zurek.

The 2014 passage of Comet A1 Siding Spring through the inner solar system. Credit: NASA/JPL-Caltech

Comet A1 Siding Spring is projected to pass within just 138,000 kilometres of Mars on October 19^th, 2014. This is one-third the Earth-Moon distance, and 10 times closer than the closest recorded passage of a comet by the Earth, which was Comet D/1770 Lexell in the late 18^th century. The comet will also miss the Martian moons of Phobos and Deimos, which have the closest orbits of any moons in the solar system at just 5,989 and 20,063 kilometres above the surface of Mars, respectively.

Assets in orbit around the Red Planet are also slated to observe the close approach and passage of Comet A1 Siding Spring, as well as any extraterrestrial meteor shower that its dust may generate.

“We could learn about the nucleus – its shape, its rotation, whether some areas on its surface are darker than others,” Zurek said in a recent NASA/JPL press release.

The rovers Curiosity and Opportunity are currently active on the surface of Mars. Above in orbit, we’ve got the European Space Agency’s Mars Express, and NASA’s Mars Odyssey and the Mars Reconnaissance Orbiter (MRO). These will be joined by India’s Mars Orbiter Mission and NASA’s Mars Atmosphere and Volatile Evolution (MAVEN) spacecraft just weeks prior to the comet’s passage.

“A third aspect for investigation could be what effect the infalling particles have on the upper atmosphere of Mars,” Zurek said. “They might heat it and expand it, not unlike the effect of a global dust storm.”

Just last year, Mars based spacecraft caught sight of the ill-fated sungrazer Comet C/2012 S1 ISON as it passed Mars. But that dim passage yielded a scant pixel-sized view in the eyes of MRO’s HiRISE camera; Comet A1 Siding Spring will pass 80 times closer than Comet ISON and could yield a view of its nucleus dozens of pixels across.

Though the tenuous Martian atmosphere will shield to surface rovers from any micro-meteoroid impacts, they may also be witness to a surreptitious meteor shower from the debris shed by the comet, a first seen from the surface of another world.

But engineers will also be assessing the potential hazards that said particles may posed to spacecraft orbiting Mars as well.

“It’s way too early for us to know how much of a threat Siding Spring will be to our orbiters,” said JPL’s Mars Exploration Program chief engineer Soren Madsen recently. “It could go either way. It could be a huge deal or it could be nothing – or anything in between.”

In a worst case scenario, Mars orbiting spacecraft would be shuttered and oriented to “shelter in place” as the dust from the comet passes. There’s precedent for this in Earth orbit, as precious assets such as the Hubble Space Telescope were closed for business during the Leonid meteor storm of 1998.

“How active will Siding Spring be in April and May? We’ll be watching that,” Madsen continued. “But if the red alarm starts sounding in May, it would be too late to start planning how to respond. That’s why we’re doing what we’re doing right now.”

Comet A1 Siding Spring was the first comet discovered in 2013 at 7.2 Astronomical Units (AUs) distant. From our Earth based perspective, the comet will reach opposition on August 25^th at 0.96 AU from the Earth, and approach 7’ from Mars on October 19^th in the constellation Ophiuchus in evening skies. The comet reaches perihelion just 4 days later, and is slated to be a binocular comet around that time shining at magnitude +8.

The comet nucleus itself is moving in a retrograde orbit relative to Mars. Particles from A1 Siding Spring will slam into the atmosphere of Mars — and any spacecraft that happens to be in their way — at a velocity of 56 kilometres per second. For context, the recent January Quadrantids have a more sedate atmospheric impact velocity of 41 kilometres a second.

The unfolding 2014 drama of “Mars versus the Comet” will definitely be worth keeping an eye on… more to come!

January 14, 2014December 23, 2015 by David Dickinson

A Possible Meteor Shower from Comet ISON?

Hey, remember Comet C/2012 S1 ISON? Who can forget the roller-coaster ride that the touted “Comet of the Century” took us on last year. Well, ISON could have one more trick up its cosmic sleeve –although it’s a big maybe — in the form of a meteor shower or (more likely) a brief uptick in meteor activity this week.

In case you skipped 2012 and 2013, or you’re a time traveler who missed their temporal mark, we’ll fill you in on the story thus far.

Comet ISON was discovered by Artyom Novichonok and Vitali Nevski on September 21^st, 2012 as part of the ongoing International Scientific Optical Network (ISON) survey. Shortly after its discovery, researchers knew they had spotted something special: a sungrazing comet already active at over 6.4 Astronomical Units (A.U.s) from the Sun. The Internet then did what it does best, and promptly ran with the story. There were no shortage of Comet ISON conspiracy theories for science writers to combat in 2013. It’s still amusing to this day to see predictions for comet ISON post-perihelion echo through calendars, almanacs and magazines compiled and sent to press before its demise.

ISON back in the day. Credit-Efrain Morales Rivera, Jaicoa Observatory Aguadilla, Puerto Rico

The frenzy for all things ISON reached a crescendo on U.S. Thanksgiving Day November 28^th 2013, as ISON passed just 1.1 million kilometres from the surface of the Sun. Unfortunately, what emerged was a sputtering ember of the comet formerly known as ISON, which faded from view just as it was slated to reenter the dawn sky.

Hey, we were crestfallen as well… we had our semi-secret dark sky site pre-selected for ISON imaging post-perihelion and everything. Despite heroic searches by ground and space-based assets, we’ve yet to see any compelling recoveries of Comet ISON post-perihelion.

This week, however, Comet ISON may put on its last hurrah, in the form of a minor meteor shower. We have to say from the outset that we’re highly skeptical that an “ISON-id meteor outburst” will grace the skies. Known annual showers are fickle enough, and it’s nearly impossible to predict just what might happen during a meteor shower with no past track record.

But you won’t see anything if you don’t try. If anything is set to occur, the night of January 15^th into the 16^th might just be the time to watch. This is because the Earth will cross the orbital plane of ISON’s path right around 9:00 PM EST/2:00 UT. Last year, ISON passed within 3.3 million kilometres of the Earth’s orbit on its inbound leg. Earlier last year, ISON was estimated to have been generating a prodigious amount of dust, at a rate of about 51,000 kilograms per minute. Any would-be fragments of ISON outbound would’ve passed closest to the Earth at 64 million kilometres distant on the day after Christmas last year. Veteran sky observer Bob King wrote about the prospects for catching ISON one last time during this month back in December 2013.

A simulation showing Earth crossing the plane of Comet ISON’s orbit early on January 16th. Credit: NASA/JPL Solar System Dynamics Small Body Database Browser.

Another idea out there that is even more unlikely is the proposal that dust from Comet ISON may generate an uptick in noctilucent cloud activity. And already, a brief search of the internet sees local news reports attempting to tie every meteor observed to ISON this week, though no conclusive link to any observed fireball has been made.

The radiant to watch for any possible “ISON-ids” sits near the +3.5 magnitude star Eta Leonis in the sickle of Leo. Robert Lundsford of the American Meteor Society notes in a recent posting that any ISON-related meteors would pass through our atmosphere at a moderate 51 kilometres a second, with a visible duration of less than one second.

Note that meteor activity has another strike against it, as the Moon reaches Full on the same night. In fact, the Full Moon of Wednesday January 15^th sits in the constellation Gemini,just 32 degrees away from the suspect radiant!

Another caveat is in order for any remaining dooms-dayers: no substantial fragments of ISON are (or ever were) inbound and headed towards our fair planet. Yes, we’re seeing rumblings to this effect in the pseudoscience netherworlds of ye ole Internet, along with ideas that ISON secretly survived, NASA “hid” ISON, ISON cloaked like a Romulan Bird of Prey, you name it. Just dust grains, folks… a good show perhaps, but nothing more.

As near as we can tell, talk of a possible meteor shower generated from Comet ISON goes all the way back to a NASA Science News article online from April 2013. Radio observers of meteor showers should be alert for a possible surge in activity this week as well, and it may be the case that more radio “pings” will be noted than visual activity what with the light-polluting Full Moon in the sky. The radiant for any would-be “ISON-ids” transits highest in the sky for northern hemisphere observers at around 2 AM local.

But despite what it has going against it, we’d be thrilled if ISON put on one last show anyhow. It’s always worth watching for meteor activity and noting the magnitude and from whence the meteor came to perhaps note the pedigree as to the shower it might belong to.

The next annual dependable meteor shower won’t be until the night of April 21^st to the 22^nd, when the Spring Lyrids are once again active. And this year may just offer a special treat on May 24^th, when researchers have predicted that the Earth may encounter debris streams laid down by Comet 209P LINEAR way back in 1803 and 1924… Camelopardalids, anyone? Now, that’s an exotic name for a meteor shower that we’d love to see trending!

-Catch sight of any “ISON-ids?” we’d love to see ‘em… be sure to post said pics at Universe Today’s Flickr pool.