Comet Catalina

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Comet Catalina

http://www.forbes.com/sites/startswithabang/2015/11/11/comet-catalina-to-pass-by-earth-for-the-final-time/


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Forbes /Science
Nov 11, 2015 @ 07:53 PM 20,628 views
Ethan Siegel,    Contributor

Comet Catalina To Pass By Earth For The Final Time

Our Solar System is a relatively quiet place, which it ought to be after some 4.5 billion years. While the early days saw a flurry of violent activity, with collisions, gravitational interactions and even ejections, things have settled down an awful lot. In the inner Solar System, the four rocky planets orbit peacefully, undisturbed by one another. Beyond them, thousands of smaller, rocky bodies pass by in the asteroid belt. Out a little farther, the four gas giants — themselves failed stars — host their own complex planetary systems with moons of their own, while the Kuiper Belt and Oort Cloud lie even beyond that.

Image credit: NASA / JPL.

But every so often, a Kuiper Belt object wanders too close to Neptune, or a passing encounter with a star or rogue planet perturbs the Oort Cloud, or one of those outer, icy bodies passes too close to another. When this happens, there's a reasonable probability that one of those distant, lonely worlds will change its trajectory and pass through the inner Solar System.
And when it nears us, passing interior to the orbit of Jupiter, it begins to heat up.


Image credit: ESA/Rosetta/NAVCAM.


Tails begin to develop, and debris flies off of these bodies, creating the phenomenon we know as a comet. While we normally think of comets as stable, recurring phenomena — like Halley's Comet, which returns every 76 years — the reality is a lot more complex. As comets make their periodic trips through the inner Solar System, they often pass by planets and/or the Sun relatively closely, and as such, have their orbits gravitationally influenced by these bodies.

When the right combination of circumstances occur, one of two fates almost always awaits such a comet: either it will hurtle into (or pass too close to) the Sun and burn up, or its trajectory will change enough to eject it from the Solar System entirely!


While the first possibility is exactly what happened to Comet ISON less than two years ago, the latter possibility is what's in store for the next comet headed our way: Comet Catalina, coming close to Earth later this month. Originating from the Oort Cloud, this icy body used to take millions of years to orbit the Sun just a single time, but a gravitational encounter with something out there flung it into the inner Solar System.


Image credit: NASA / JPL-Caltech, NEOWISE.

On November 15th, it will make its closest approach to the Sun — perihelion — passing interior to the orbit of Earth and reaching a minimum distance of 123 million km (76.5 million miles) from the Sun. After that, it will make its closest approach to Earth, where it may well become a naked-eye comet, and will certainly be visible through even a cheap pair of binoculars.



Image credit: Starry Night Education Software, via David Dickinson at http://www.universetoday.com/122611/comet-us10-catalina-our-guide-to-act-ii/.

On December 17th, it will cross the celestial equator, becoming visible everywhere in the Northern Hemisphere. It will head towards the orange giant, Arcturus, which is the brightest star in the Northern Hemisphere, passing within one degree of it on New Year's Day. But after that, Comet Catalina will begin to dim, passing near the Big Dipper and headed out of the Solar System.



Image credit: NASA / JPL-Caltech; NEOWISE.

Yes, not to the outer Solar System, but out of the Solar System. During this trip close to the Sun, Comet Catalina has acquired just a tiny bit of extra kinetic energy, where at perihelion, it will travel at a maximum speed of 46,400 m/s relative to our Sun: just 25 m/s faster than our Sun's escape velocity. This means that, over the next thousand years or so, it will head back into the Oort cloud and slow down, but will keep moving past all the other objects out there, eventually floating into true interstellar space on a timescale of hundreds of thousands of years.

Although in many ways, the visuals will be spectacular:
•the tail will be over 500,000 miles (800,000 km) long,
•the coma (or halo) around the comet's nucleus will be green in color,
•and there's a good chance it will be visible to the naked eye,

it will at best appear as a faint "smudge" under dark sky conditions, best viewed in the pre-dawn sky. Nevertheless, unless something comes along to change the comet's trajectory again, unexpectedly, this will be our last and only chance to see it as a species. Like everything in the Universe, this object is destined to depart from our reach, but on a much shorter timescale than any other natural object found so far.

Ethan Siegel is the founder of Starts With A Bang, NASA columnist and professor at Lewis & Clark College. Follow him on Twitter, Facebook, Google+, Tumblr and support his Patreon.



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http://www.skyandtelescope.com/observing/comet-catalina-sails-into-northern-skies111120151111/


Comet Catalina Sails Into Northern Skies
By: Bob King | November 11, 2015

- See more at: http://www.skyandtelescope.com/observing/comet-catalina-sails-into-northern-skies111120151111/#sthash.giYiNILs.dpuf

more photos at link

Get ready to lose some sleep —  Comet Catalina (C/2013 US10) will be arriving soon! After making a hairpin turn around the Sun at perihelion on November 15th, the comet will surge into the dawn sky for Northern Hemisphere skywatchers and put on a great show by month's end. Early on, binoculars will show the comet's small, bright coma with a whisper of a tail. Naked-eye sightings may be possible by mid-December.

There's been a lot of buzz about the comet, since many of us expected Comet Catalina to depart the solar glare pumped up to magnitude 3, making it the brightest expected fuzzball of the year. Maybe it will still. But in September, the comet's rate of brightening began to flag. Revised estimates now call for it to top out between magnitude 5 and 6 by year's end.

From late March through mid-October, Catalina's path confined its visibility to southern eyes only. Chris Wyatt of New South Wales, Australia, made one of the last visual observations on October 16th before the comet disappeared in the solar glare. Using 10×70 binoculars, he estimated a magnitude of 7 with a 7?-wide, well-condensed, greenish coma, and short ion tail pointing southeast.

Through his 10-inch Dobsonian reflector, the coma expanded to 8.2? with a longer 35? tail. Wyatt noted that Catalina responded well to a Swan Band filter, a narrow bandpass filter tuned to oxygen and carbon emissions that enhances the view of  gassy (versus dusty) comets. With the filter in place he saw significant brightening in the inner coma.



C/2013 US10 is an Oort Cloud comet with a steeply inclined orbit of 149°. It's spent much of its time lately below the plane of the solar system, out of view of Northern Hemisphere skywatchers. After solar conjunction at mid-month, it will transition to northern skies and arc over the inner planets. On January 12, 2016, the comet comes closest to Earth at 66.9 million miles (107.7 million km).
NASA / JPL

Discovered by the Catalina Sky Survey on Halloween 2013, the comet received the "US10" designation because it was initially thought to be an asteroid in a short period orbit. After more observations to refine its path and additional photographs that revealed telltale comet fuzz, astronomers realized they'd run into a denizen from the Oort Cloud, knocked our way by the close passage of some nameless star long ago. At the time of discovery, Catalina glowed at only 19th magnitude some 7.7 a.u. from Earth. Typical of new arrivals, it dove into the inner solar system on a steeply inclined orbit.
The comet pursues a northerly track through Virgo when it returns at dawn around November 24th, appearing 8° high in the southeastern sky 70 minutes before sunrise. By the 28th, it will have climbed to 10° in a dark sky shortly before the start of dawn.

Now for the bad news. A bright Moon will put a temporary damper on the comet's rise to fame from November 24th through December 3rd. From there on out, though, it's smooth sailing until the Moon returns for Round 2 at the winter solstice.

Catalina glides northward at nearly 1° per day in late December as it crosses from Virgo into Boötes on a beeline for Arcturus. On the morning of January 1st, the comet skims ½° southwest of that orange luminary in a remarkable conjunction highlighting the arrival of the new year. Photo anyone?


C/2013 US10 spends its first few weeks after conjunction climbing northward through Virgo near Spica. Ticks mark its position at 0h Universal Time every three days. Stars are plotted to 6th magnitude. Click on the image for a large, color PDF map. Sky & Telescope


After a relatively slow start in Virgo, the comet races across the sky, becoming a circumpolar object in Ursa Major by mid-January and visible all night long from mid-northern latitudes. Click on the image for a large black-and- white PDF chart. Sky & Telescope

The comet passes closest to Earth at 0.72 a.u. on January 12th, then buzzes Mizar in the Big Dipper's handle on January 14–15, hurrying along at the rate of 2° per day or 5? an hour — fast enough to easily detect motion in 30 minutes or less. After mid-month, it's expected to fade quickly.

In this dark time of year, when the Sun bows low in the south, we welcome a potentially bright comet to lift our spirits and add celestial pizzazz to the seasonal holidays of Thanksgiving, Christmas, and New Year's.

Who really knows how bright Comet Catalina will get? Will it break into multiple comets after perihelion? First-time visitors from the Oort Cloud often do surprising things. No matter what Catalina has up its sleeve, its tour will be be a brief one.

After several million years of inbound travel, perturbations induced by the planets will boot it out of the solar system and into interstellar space. We're glad for the chance to share our table with a visitor who spent so much time getting here but can only stay a short while.

Comet Catalina highlights:

* November 24 — Approximate date of first visibility in the dawn sky
* December 7 — Catalina gets company! The comet pairs up with the planet Venus and the waning crescent Moon this morning. From the central United States, Venus shines 4° southwest and the Moon 5° southwest of the comet.
* December 23–24 — Comet crosses into Boötes
* January 1, 2016 — Close pass (0.5°) of Arcturus on the first day of 2016
* January 9 — Comet crosses into Canes Venatici
* January 12 — Closest to Earth at 66.9 million miles
* January 14 — Comet crosses into Ursa Major
* January 14–15 — Passes just 1° north of Alkaid, the star at the end of the Big Dipper's handle
* January 16 — Passes 2° southwest of the 8th-magnitude galaxy, M101
* January 17 — Passes 3.4° northeast of the double star Mizar in the bend of the Big Dipper's handle
* January 21 — Comet crosses into Draco
* January 25 — Comet crosses into Camelopardalis



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https://en.wikipedia.org/wiki/C/2013_US10




http://earthsky.org/space/comet-catalina-c2013-us10-november-december-january-2015-2016
Comet Catalina this month and next!

Comet C/2013 US10 (Catalina) visible in binoculars, maybe visible to the eye, in November. It'll be near the moon and Venus before dawn in early December.





http://www.universetoday.com/122611/comet-us10-catalina-our-guide-to-act-ii/
Comet US10 Catalina: Our Guide to Act II

by David Dickinson   on October 6, 2015


http://apod.nasa.gov/apod/ap150818.html
Astronomy Picture of the Day

Discover the cosmos! Each day a different image or photograph of our fascinating universe is featured, along with a brief explanation written by a professional astronomer.

2015 August 18

Announcing Comet Catalina 
Image Credit & Copyright:  Ian Sharp

Explanation:  Will Comet Catalina become visible to the unaided eye? Given the unpredictability of comets, no one can say for sure, but it seems like a good bet. The comet was discovered in 2013 by observations of the Catalina Sky Survey. Since then, Comet C/2013 US10 (Catalina) has steadily brightened and is currently brighter than 8th magnitude, making it visible with binoculars and long-duration camera images. As the comet further approaches the inner Solar System it will surely continue to intensify, possibly becoming a naked eye object sometime in October and peaking sometime in late November. The comet will reside primarily in the skies of the southern hemisphere until mid-December, at which time its highly inclined orbit will bring it quickly into northern skies. Featured above, Comet Catalina was imaged last week sporting a green coma and two growing tails.