ALAN'S COMETS

TALLY ENTRIES 661-670

661. COMET FLEWELLING C/2019 D1          Perihelion: 2019 May 11.85, q = 1.577 AU

Over 3 1/2 months have elapsed since I made a "real-time" addition to my comet tally. (The previous entry, which I placed on the tally in late March, was a retroactive addition of an object that I observed almost 20 years ago.) This is the longest period of time that I have gone without a tally addition in 19 years, and it has coincided with a general slowdown in cometary activity (in contrast to the high level of activity that was going on at the beginning of this year).

A lot has happened during these past 3 1/2 months. During the latter part of January Vickie and I traveled to Adelaide, South Australia for three weeks, where I taught a brief course on the "small bodies" of the solar system as a part of the International Space University's Southern Hemisphere Space Studies Program (and also was able to visit my older son Zachary and his girlfriend Karina, who have resided in Adelaide for the past three years while she has been pursuing doctoral studies at Flinders University). Vickie moved in with me at the end of February, making us full-fledged "domestic partners," and she has commenced turning my erstwhile "bachelor pad" into an actual respectable home. Meanwhile, over the fairly recent past I have been busy developing an expanded educational program around the solar system's "small bodies" which I hope to implement next year, and I plan to be making a statement about it (on this website) in a couple of months. Finally, in early March I "celebrated" birthday number 61, and for a birthday present Vickie treated me to a concert by Bob Seger that was held in Albuquerque; during that same trip we visited Santa Fe where I was able to meet with some educators and (together with Vickie) was formally introduced on the floor of the New Mexico State Senate.

The comet that ended the long drought of tally additions was discovered on February 26, 2019, by Heather Flewelling with the ATLAS program in Hawaii, utilizing the ATLAS telescope at Mauna Loa. Although it was too faint to attempt visually at the time, it was nevetheless relatively bright as far as recent survey discoveries go, and two weeks later I sucessfully obtained images of it with one of the Las Cumbres Observatory telescopes while it was still listed on the Minor Planet Center's Possible Comet Confirmation Page. (Unfortunately, the star images were too trailed to allow valid astrometry to be performed.) After the comet's discovery was announced I attempted it visually a couple of times in early April, without success. After the April full moon I made another attempt on the morning of April 29 and suspected a very faint, diffuse, 14th-magnitude object, however the rising crescent moon and some possible thin clouds that moved in prevented me from confirming it. After one day of cloudy weather I was able to observe again, under good sky conditions, on the morning of May 1, and was able to verify my earlier suspect.

Comet Flewelling is traveling in a moderately-inclined orbit (inclination 34 degrees) with an approximate period of 1700 years. It is currently located in western Pegasus and is traveling towards the northeast at 50 arcminutes per day; it passes slightly to the northwest of the "Great Square" during the last week of May and enters western Andromeda during the second week of June, passing three degrees north of the Andromeda Galaxy M31 shortly after mid-July. By that time its motion will have slowed down to somewhat under 20 arcminutes per day and will be turning more directly westward; it reaches its farthest north point (just south of declination +47 degrees) in mid-August, is at its stationary point a week and a half later, and is at opposition in early October. As far as the comet's brightness is concerned, with its being at perihelion in just a little over a week and being closest to Earth (1.57 AU) at the end of May it probably won't get much brighter than it already is, unless it undergoes some sort of post-perihelion brightening (which is not unprecedented for long-period comets that have made previous returns, as is the case with this one). In any event, though, I doubt if I will be following this comet much beyond the end of June.

    Comet Flewelling C/2019 D1, as imaged by telescopes of the Las Cumbres Observatory. LEFT: March 13, 2019 -- at which time it was still listed on the Possible Comet Confirmation Page -- from the South African Astronomical Observatory. RIGHT: April 28, 2019 -- a little over 14 hours before I first picked it up visually -- from Siding Spring Observatory in New South Wales.

Despite this latest addition to my tally, the comet activity will likely remain quite low for some time yet, and I don't expect this comet or either of the other two comets I am presently following -- one of which I am already about done with -- to be around for too much longer. It is always possible, of course, that some unexpected bright comets could appear in the not-too-distant future, but otherwise things will probably be pretty slow until I am able to pick up some of the expected comets later this year, including some of those listed on the "Notable Upcoming Comets" page.

CONFIRMING OBSERVATION: 2019 May 1.42 UT, m1 = 14.2, 0.8' coma, DC = 1-2 (41 cm reflector, 229x)

 

662. COMET LEMMON C/2018 R3          Perihelion: 2019 June 7.20, q = 1.291 AU

I've commented before in various previous entries about the random nature of appearances of comets in our skies; there are times when cometary activity can be quite high, as was the case during the last few months of last year, and there are times when the activity is very slow, as it is now. A symptom of the present low level of activity was the 3 1/2 months that elapsed before the previous entry to my tally; in general, that slow activity is continuing, but in somewhat of an unusual twist barely over a week elapsed between the addition of my previous entry and my addition of this one.

This particular comet was discovered on September 7, 2018, by Brian Africano during the course of the Mount Lemmon Survey based in Arizona. It was a faint object of about 19th magnitude that initially appeared asteroidal -- hence the name "Lemmon" -- but other observers soon began reporting it as being cometary. It remained faint for the next few months before disappearing into evening twilight, and after conjunction with the sun in late February it began emerging into the morning sky towards the end of March. I made an attempt for it in twilight in early April and didn't see anything, and CCD images that were taken shortly thereafter by other observers indicated that it was still quite faint, even more so than expected. While the viewing prospects were never very good, it now looked like the comet would remain too faint to become visually detectable.

It nevertheless did seem to brighten some over the next few weeks, according to CCD images that I saw. (Unfortunately, it remained too low to access with the Las Cumbres Observatory telescopes.) After the April full moon I made another attempt on the morning of the 29th -- the same morning I first observed the previous comet -- and didn't see anything, but when I tried for it again on the morning of May 8 I was rather surprised to see a faint, diffuse, 13th-magnitude patch of light that moved noticeably against the background stars over a period of 15 to 20 minutes. While there were no real doubts in my mind that I had indeed observed the comet, I was nevertheless delighted to see a CCD image that was posted later that same day by Austrian amateur astronomer Michael Jaeger; he had taken the image a few hours before my visual observation, and it clearly showed the comet as being bright enough to be within my visual range.

The viewing geometry remains poor throughout Comet Lemmon's apparition. It is presently low in the northeastern sky at dawn, being located in western Perseus some six degrees east of the star Theta Cassiopeiae, and is actually at its maximum elongation from the sun, just under 41 degrees. It is traveling towards the east-northeast at slightly over one degree per day, passing through the northern regions of the two members of the "Double Cluster" (NGC 869 and NGC 884) on May 14 and crossing into southeastern Cassiopeia two days later before entering Camelopardalis five days after that (while passing half a degree south of the open star cluster Stock 23 in the process). The comet is closest to Earth (1.92 AU) on May 23, is at its maximum northerly declination (+60 degrees) four days later, and is in conjunction with the sun (38 degrees north of it) just before the end of May. While technically it is an evening-sky object at the time of perihelion passage on June 7, it is buried in twilight at a farily small elongation, and the elongation keeps shrinking for the next several weeks as the comet recedes from perihelion on the far side of the sun from Earth. It finally becomes accessible in the morning sky during the last two to three months of 2019 but it will likely be very faint by then.

Even though the comet's recent brightening trend suggests it might brighten still further as it approaches perihelion, its poor placement in the sky will keep it from being easily observed. Theoretically, I have about one week to view it before the full moon washes out the morning sky, however since my initial sighting on the 8th the first of a series of rain storms has arrived in southern New Mexico, and the current forecast indicates that the rain may continue throughout the rest of that week. It is thus entirely possible that my sighting of the comet on the 8th will remain my only observation of it; should that be the case Comet Lemmon would become my 33rd "one-time wonder," a group that constitutes almost exactly 5% of all the comets on my tally.

INITIAL OBSERVATION: 2019 May 8.44 UT, m1 = 13.3, 1.3' coma, DC = 3 (41 cm reflector, 70x)

UPDATE (May 12, 2019): Comet Lemmon turns out not to be a "one-time wonder" after all! We've had a brief break in the series of rain storms that are currently traveling across southern New Mexico, and although I had to play a little "dodge-the-clouds" this morning I was able to view the comet again. While my observation was necessarily rather brief, it was enough to see that the comet is slightly brighter and larger than it was four days ago.

It is reasonable to expect that Comet Lemmon might continue brightening as it approaches perihelion early next month, however the decreasing elongation, as well as the full moon which will be arriving in a few days, will likely prevent it from becoming a prominent object. I am quite probably finished with it.

MOST RECENT OBSERVATION: 2019 May 12.44 UT, m1 = 13.0, 1.6' coma, DC = 3 (41 cm reflector, 70x)

 

       

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