COMET RESOURCE CENTER

NOTABLE UPCOMING COMETS

Last updated: December 28, 2018

For planning purposes, on this page I will list the incoming comets that are expected to become moderately bright or otherwise notable within the next one to two years, and which I expect to add to my tally (if I haven't already). I don't intend this list to be exhaustive, but instead will focus on those comets that are worthy of attention from sky-watchers and other interested people (including, certainly, students) who would not normally be considered "comet astronomers." I plan to update this page every one to two months and/or as necessary.

The "long-range" comets listed at the end of this page are, as implied, mentioned here primarily for long-range planning purposes.

          

(944) HIDALGO     (Perihelion 2018 October 26)

The first-known and, instrinsically, brightest of the potentially "extinct" of "dormant" Jupiter-family comets is well-placed for observation from the northern hemisphere, being located in northern circumpolar skies for the last three months of 2018 and first three months of 2019, reaching a peak northerly declination of +81.4 degrees in early February before going through opposition later that month. Hidalgo is nearest Earth (1.45 AU) in late November and should be near its peak brightness of 14th magnitude around that time; it should remain near that brightness for several months.

NOTE ADDED OCTOBER 2, 2018: I successfully picked up Hidalgo -- slightly fainter than magnitude 14 1/2, and (as expected) stellar in appearance -- in mid-September, and expect to follow it for the next few months, according to the above scenario. I also hope to do some deep imaging with the larger Las Cumbres Observatory telescopes, in the (admittedly faint) hope that some images (and/or images taken by other observers elsewhere) will show cometary activity of some kind. I observed Hidalgo during both its 1991 and 2005 returns (including with CCD on the latter return), and if it were to exhibit any such activity I would add all three returns to my tally retroactively.

NOTE ADDED OCTOBER 15, 2018: On October 14 I successfully obtained a 5-minute-long exposure of Hidalgo with the 2-meter LCO Faulkes Telescope North at Haleakala Observatory in Hawaii (which I have posted on the LCO images page). Hidalgo exhibits a completely stellar appearance in the image, although several nearby galaxies do exhibit a diffuse appearance.

NOTE ADDED DECEMBER 28, 2018: Hidalgo has remained between magnitudes 14 and 14.5 up through now, and I expect to be able to follow it for at least a few more weeks; it has also remained completely stellar in appearance. Meanwhile, on December 23 I successfully obtained another 5-minute-long exposure with the 2-meter LCO Faulkes Telescope North at Haleakala (and have posted this image on the LCO images page); the image is "noisy" due to being taken at the time of full moon, but continues to show Hidalgo as being entirely stellar. At this point I consider it very unlikely that Hidalgo will exhibit any kind of cometary activity during the current return.

     

COMET AFRICANO C/2018 W2      (Perihelion 2019 September 6)

This recent discovery from the Mt. Lemmon Survey in Arizona is traveling in a steeply-inclined retrograde orbit (inclination 117 degrees) and spends the first eight months of 2019 in northern circumpolar skies, passing to within 70 arcminutes of the north celestial pole shortly before mid-March, although it will likely still be too faint for visual observations at that time. After the end of August it rapidly plunges southward and passes 0.49 AU from Earth near the end of September -- at which time it is also near opposition -- and then spends the last two months of the year between declinations -40 and -45 degrees. Brightness predictions for newly-discovered long-period comets are always problematical, but this one should reach at least 9th or 10th magnitude, possibly brighter, around the time it is nearest Earth.

     

A/2018 V3      (Perihelion 2019 September 8)

This discovery by the Pan-STARRS program is traveling in a very elongated comet-like orbit with an inclination of 165 degrees (i.e., retrograde, but inclined 15 degrees with respect to the ecliptic) but, thus far anyway, has appeared entirely asteroidal. Shortly after mid-August 2019 it passes 0.38 AU from Earth as it and Earth fly past each other; at that time it will be near opposition and located near a declination of -30 degrees, and will be traveling rapidly westward at over 5 degrees per day. Even if it remains asteroidal it should reach about 13th magnitude around the time it is nearest Earth; if it should begin to exhibit cometary activity it may well be somewhat brighter than that.

         

COMET 289P/BLANPAIN      (Perihelion 2019 December 20)

A lot of mystery surrounds this comet, which was lost between its original discovery in 1819 and its accidental re-discovery (as an asteroid) in 2003; it has exhibited some sporadic cometary activity (including at least one outburst) since that time. It passes 0.09 AU from Earth on January 10, 2020, and will be well placed for observations from the northern hemisphere around that time; indeed, it is favorably placed throughout its entire return to perihelion. Depending upon what level of activity it exhibits, it might -- or might not -- become somewhat bright.

         

COMET PANSTARRS C/2017 T2      (Perihelion 2020 May 4)

This intrinsically bright long-period comet was discovered by the Pan-STARRS program in October 2017, over 2 1/2 years before its perihelion passage. After being in conjunction with the sun in May 2019 it begins to emerge into the morning sky by July or August, and may already be visually detectable at that time. The comet is closest to Earth (1.52 AU) in late December 2019 and then spends most of the first six months of 2020 in northern circumpolar skies (and conveniently placed for viewing in the evening sky). Its somewhat large perihelion distance of 1.62 AU will probably keep it from becoming very bright, but a peak brightness between 6th and 8th magnitudes -- which it may maintain for several weeks -- would seem to be fairly likely.

NOTE ADDED OCTOBER 13, 2018: Some recent reports and CCD images I've seen have suggested that this comet may be running a bit brighter than originally expected, which in theory could be good news regarding its display when near perihelion in 2020. These reports inspired me to take an image with the Las Cumbres Observatory on October 9 (which I have posted on the LCO images page), and which in turn inspired me to make a visual attempt the following night -- which was unsuccessful. While the comet does indeed seem to be running brighter than expected (at least for the time being), it is still too faint for visual observations.

The comet is at opposition in mid-November 2018 and is (temporarily) closest to Earth (5.05 AU) a month later, and remains accessible in the evening sky until disappearing into twilight towards the end of March 2019. I'll probably continue to make occasional visual attempts for it throughout this time, and if does become bright enough to be detected that would be an encouraging sign. On the other hand, the comet appears to be a first-time visitor from the Oort Cloud, which would tend to suggest it might not become as bright as we might wish when it is near perihelion. As is always the case with such comets, we'll just have to wait and see what it actually does.

         

COMET 2P/ENCKE      (Perihelion 2020 June 25)

I have observed this famous comet on a dozen returns going back to 1970, most recently in 2017 (no. 610); I discuss it in my entries for its 2007 return (no. 402) and its 2013 return (no. 531). I will almost certainly not be observing it in 2020; it is impossibly placed for observation from the northern hemisphere prior to perihelion but does become accessible in the evening sky for southern hemisphere observers during the first half of July, where it should remain visually detectable for perhaps a month or so before fading out. The viewing circumstances for the northern hemisphere are much more favorable during the subsequent return to perihelion in October 2023.

     

     

LONG-RANGE COMETS

     

COMET PANSTARRS C/2017 K2     (Perihelion 2022 December 19)

Despite being located at a heliocentric distance of 16.1 AU, this comet was clearly active, and a relatively bright 19th to 20th magnitude, when discovered in May 2017. Even more remarkably, in pre-discovery images taken as far back as May 2013, the comet is clearly active even at a heliocentric distance of 23.7 AU. The high intrinsic brightness, and high activity level at such large distances from the sun, is somewhat reminiscent of Comet Hale-Bopp C/1995 O1 (no. 199).

Unfortunately, the comet's perihelion distance is still a relatively large 1.80 AU. Even more unfortunately, the comet is on the far side of the sun from Earth at the time, never coming closer than 2.23 AU. While naked-eye visibility, perhaps even conspicuous naked-eye visibility, would seem to be almost a certainty, the comet is unlikely to become "Great."

And even more unfortunately for northern hemisphere observers, the comet is in southern circumpolar skies at the time of perihelion. Indeed, the comet is inaccessible from the northern hemisphere for almost a full year (September 2022 through August 2023).

 

Comet PANSTARRS C/2017 K2 (small diffuse object in center) as imaged on March 6, 2018, by the Las Cumbres Observatory facility at McDonald Observatory in Texas. At the time this image was taken, the comet's heliocentric distance was 14.4 AU.
COMET 12P/PONS-BROOKS     (Perihelion 2024 April 21)

This "classical" Halley-type comet (period 70 years) last returned in 1954, four years before I was born. The viewing geometry in 2024 is, unfortunately, rather unfavorable, as during the run-up to perihelion the comet remains on the far side of the sun from Earth and is only visible for a brief period of time in the northwestern sky after dusk, at a small elongation (37 degrees in mid-March, shrinking to 28 degrees by month's end and to 23 degrees by perihelion). Despite the poor viewing geometry, the comet is intrinsically rather bright, and should reach a peak brightness close to 5th magnitude. After perihelion the comet travels southward and is visible from the southern hemisphere as it recedes and fades.

COMET 13P/OLBERS     (Perihelion 2024 June 30)

This other "classical" Halley-type comet (period 68 years) last returned in 1956, two years after the above comet and two years before I was born. Also as with the above comet, the viewing geometry remains relatively poor, with the comet's remaining on the far side of the sun from Earth; on the other hand, it is almost identical to the viewing geometry in 1956. It remains in the northern hemisphere's evening sky throughout the period of prime visibility, albeit at a small elongation (dropping below 30 degrees in early May, to a minimum of 25.5 degrees in early June before increasing back to 30 degrees by perihelion to a maximum of 39 degrees in August). Based upon the reported brightnesses in 1956, the comet should reach a peak brightness between 6th and 7th magnitude.

Around mid-April 12P/Pons-Brooks and 13P/Olbers will be located some 15 degrees from each other, the latter comet being higher (to the east and north) of the former one.

     

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