Comet U1 NEOWISE: A Possible Binocular Comet?

U1 NEOWISE
U1 NEOWISE
Comet C/2016 U1 NEOWISE on December 23rd as seen from Jauerling, Austria. Image credit: Michael Jäger.

Well, it looks like we’ll close out 2016 without a great ‘Comet of the Century.’ One of the final discoveries of the year did, however, grab our attention, and may present a challenging target through early 2017: Comet U1 NEOWISE.

Comet C/2016 U1 NEOWISE is expected to reach maximum brightness during the second week on January. Discovered by the Near-Earth Object Wide-field Infrared Survey Explorer (NEOWISE) space observatory on its extended mission on October 21st, 2016, Comet U1 NEOWISE orbits the Sun on an undefined hyperbolic orbit that is perhaps millions on years long. This also means that this could be Comet C/2016 U1 NEOWISE’s first venture through the inner solar system. Comet C/2016 U1 NEOWISE is set to break binocular +10th magnitude brightness this week, and may just top +6th magnitude (naked eye brightness) in mid-January near perihelion.

The orbit of Comet U1 NEOWISE. Credit: NASA/JPL.

Visibility prospects: At its brightest, Comet C/2016 U1 NEOWISE will pass through the constellations Ophiuchus to Serpens Cauda and Sagittarius, and is best visible in the dawn sky 12 degrees from the Sun at maximum brightness. This apparition favors the northern hemisphere. Perihelion for Comet C/2016 U1 NEOWISE occurs on January 13th, 2017 at 0.319 AU from the Sun, and the comet passed 0.709 AU from the Earth on December 13th.

This is the ninth comet discovered by the extended NEOWISE mission since 2014.

The pre-dawn view on the morning of December 28th. Image credit: Starry Night.

Comet C/2016 U1 NEOWISE ends 2016 and early January 2017 as a difficult early dawn target, sitting 25 degrees above the eastern horizon as seen from latitude 30 degrees north about 30 minutes before dawn. Things will get much more difficult from there, as the comet passes just 12 degrees from the Sun as seen from our Earthly vantage point during the final week of January. The comet sits 16 degrees from the Sun in the southern hemisphere constellation of Microscopium on the final day of January, though it is expected to shine at only +10th magnitude at this point, favoring observers in the southern hemisphere.

The time to try to catch a brief sight of Comet C/2016 U1 NEOWISE is now. Recent discussions among comet observers suggest that the comet may be slowing down in terms of brightness, possibly as a prelude to a pre-perihelion breakup. Keep a eye on the Comet Observer’s database (COBS) for the latest in cometary action as reported and seen by actual observers in the field.

Finding C/2016 U1 NEOWISE will be a battle between spying an elusive fuzzy low-contrast coma against a brightening twilight sky. Sweep the suspect area with binoculars or a wide-field telescopic view if possible.

The path of Comet U1 NEOWISE through perihelion on January 13th. Credit: Starry Night.

Here are some key dates to watch out for in your quest:

December

25-Crosses in to Ophiuchus.

26-Passes near +3 mag Kappa Ophiuchi.

January

1-Crosses the celestial equator southward.

3-Passes near M14.

7-Passes near the +3 mag star Nu Ophiuchi.

8-Crosses into the constellation Serpens Cauda.

10-Passes near M16, the Eagle Nebula.

11-Passes near M17 the Omega Nebula, crosses the galactic equator southward.

12-Crosses into the constellation Sagittarius.

13-Passes near M25.

16-Crosses the ecliptic southward.

27-Crosses into the constellation Microscopium.

28-Passes near +4.8 mag star Alpha Microscopii.

February

1-May drop back below +10 magnitude.

C/2016 U1 NEOWISE (23.nov.2016) from Oleg Milantiev on Vimeo.

A rundown on comets in 2016, a look ahead at 2017

C/2016 U1 NEOWISE was one of 50 comets discovered in 2016. Notables for the year included C/2013 X1 PanSTARRS, 252/P LINEAR and C/2013 US10 Catalina. What comets are we keeping an eye on in 2017? Well, Comet 2/P Encke, 41P/Tuttle-Giacobini-Kresak, C/2015 ER61 PanSTARRS, C/2015 V2 Johnson are all expected to reach +10 magnitude brightness in the coming year… and Comet 45P/Honda-Mrkos-Pajdušáková has already done so, a bit ahead of schedule. These are all broken down in our forthcoming guide to the top 101 Astronomical Events for 2017. Again, there’s no great naked eye comet on the horizon (yet), but that all could change… 2017 owes us one!

Comet Jacques Brightens: How to See it in May

A recently discovered comet is headed northward and is set to put on one of two fine performances for binocular observers in 2014 starting this week.

Comet C/2014 E2 Jacques was discovered on March 13th 2014 by Cristóvão Jacques, Eduardo Pimentel and João Ribeiro de Barros while observing from the Southern Observatory for Near Earth Asteroids Research (SONEAR) facility located near Oliveira, Brazil.

The comet was just about at +15th magnitude at the time of discovery as it glided across the southern hemisphere constellation of Centaurus.

While a majority of comet discoveries are destined to remain small and faint, Comet Jacques was immediately shown to be something special. Upon discovery of any new comet, the first task is to gain several observations hours or nights apart to accurately gauge its distance and orbit. Are astronomers looking at a small, garden variety comet close up, or a large, active one far away?

In the case of Comet Jacques, it was something in between: a comet about 1.22 Astronomical Units (A.U.s) distant at time of discovery. Comet Jacques is headed towards perihelion 0.66 A.U. from the Sun in early July and will pass 0.56 A.U. from Earth on August 28th.  Follow up observations carried out using the iTelescope at Siding Spring Australia showed a slightly elongated coma about 2 arc minutes across shortly after discovery, and the comet has recently jumped up to magnitude +8 — ahead of the projected light curve — in just the past week.

Starry Night
The path of Comet Jacques, looking west from latitude 30 degree north 45 minutes after sunset. Credit: Starry Night.

We caught our first good look at Comet Jacques last night while setting up for the Virtual Star Party. While +10 magnitude or brighter is usually a pretty good rule of thumb for binocular visibility, we found that the comet was only apparent as a fuzzy smudge viewing it with a 8” Schmidt-Cassegrain telescope using averted vision at low power. Remember, the brightness of a comet is spread out over its apparent surface area, similar to viewing a diffuse nebula. Our first telescopic views of the ill-fated comet ISON as it breeched +10th magnitude were similar. Certainly, a nearby waxing crescent Moon in Gemini last night didn’t help.

How bright will Comet Jacques get? Current projections call for it to perhaps break naked eye visibility around +6th magnitude after June 1st and reach as bright as +4th magnitude in early July near perihelion. After its first evening act in May and June, Comet Jacques will reemerge in the dawn sky for northern hemisphere observers for Act 2 and trace a path northward paralleling the galactic plane through the star rich fields of Perseus, Cassiopeia, Cepheus and Cygnus in August and September of this year. If our luck holds out, Comet Jacques will remain above 6th magnitude until early September.

Credit JPL
The path of Comet Jacques through the inner solar system. Credit: JPL solar system small body generator.

This comet also created a brief flurry of interest when it was revealed that it will pass just 0.085 AUs or 12,700,000 kilometers from Venus on July 13th, 2014. Though close, this is still 31 times the distance from Earth to the Moon. The only “eyes” that humanity has currently in operation around Venus is ESA’s Venus Express orbiter. During closest approach Comet Jacques will appear just over 3 degrees away from Venus as seen from our Earthly vantage point.

Another comet is also set to photobomb a planet, as Comet A1 Siding Spring passes a nominal distance of 0.0009 A.U.s or 135,000 kilometers from Mars this Fall on October 19th.

Comet Jacques
11 images of Comet Jacques stacked from May 3rd. Credit: Ian Griffin @IanGriffin.

The closest recorded passage of a comet near Earth was Comet  D/1770 L1 Lexell in 1770, which passed us 0.015 A.U.s or 233 million kilometres distant.

Now on to Act 1. May finds Comet Jacques spending most of the month in the long rambling constellation of Monoceros. Currently moving just under 2 degrees a day, Comet Jacques crosses the celestial equator northward this week on May 8th. You’ll note its high orbital inclination of 156.4 degrees as it speeds northward. Comet Jacques has a long orbital period gauged at over 30,000 years — the last time Comet Jacques visited the inner solar system, our ancestors had the Last Glacial Maximum period to look forward to.

Light curve
The projected light curve of comet Jacques with recent observations. Credit: Seiichi Yoshida/aerith.net.

Comet Jacques is currently the brightest comet “with a bullet,” edging out the +9th magnitude comets C/2012 K1 PanSTARRS gilding through Canes Venatici and comet C/2012 X1 LINEAR, currently residing in the constellation of Aquila the Eagle. A great place to keep up with current observations of comets is the Comet Observation Database. We’re also pinging the IAU Minor Planet Center’s quick look page for new discoveries daily.

Here are some highlights to watch out for as Comet Jacques heads towards perihelion. Passages within one degree — twice the size of the Full Moon — near stars brighter than +5th magnitude are noted unless mentioned otherwise:

May 3rd through June 1st
The celestial path of Comet Jacques from May 3rd through June 1st. Credit: Starry Night.

May 8th: Passes the +4.1 magnitude star Delta Monocerotis and crosses north of the celestial equator.

May 10th: Passes planetary nebula NGC 2346.

May 11th: Passes briefly into Canis Minor before reentering the constellation Monoceros.

May 14th: Full Moon occurs, marking the start of a favorable two week period of moonless evenings soon after.

May 24th: Passes the +4.8 magnitude star 17 Monocerotis.

May 28th: New Moon occurs, marking the return of the Moon to early evening skies.

May 29th: Passes the +4.7 magnitude star 15 Monocerotis.

May 30th: Passes the Christmas tree cluster. Photo op!

May 31st: The waxing crescent Moon passes less than 8 degrees from Comet Jacques.

June 1st: Comet Jacques reaches naked eye visibility?

June 6th: Crosses into the constellation Gemini.

June 11th: Crosses into the constellation Taurus.

June 13th: Full Moon occurs.

June 14th: Crosses the galactic plane.

June 21st: Passes into the field of view of SOHO’s LASCO C3 camera.

June 27th: New Moon occurs.

July 2nd: Reaches perihelion at 0.6638 A.U. from the Sun.

July 8th: Crosses north of the ecliptic plane.

July 13th: Passes 0.085 A.U. from Venus.

August 28th: Passes 0.56 A.U. from Earth.

And thus, Comet Jacques joins the parade of fine binocular comets in the 2014 night sky, as the stage is set for Act 2 this fall. And keep in mind, the next “big one” could grace our skies at anytime… more to come!