February 29, 2024

Comet A1 Leonard Brightens in December

On an 80,000 year orbit inbound, Comet A1 Leonard is due for ejection from the solar system after its perihelion passage early next year. The comet reached aphelion 3,500 AU remote in the Oort Cloud about 35,000 years earlier. The upcoming perihelion pass on January 3rd, 2022 will be 0.62 AU from the Sun, interior to the orbit of Venus.
The orbit of Comet A1 Leonard, set for its closest passage near Earth.
Keep in mind, A1 Leonard might be a seasoned long-lasting visitor to the inner solar system with a prospective to over-perform as it nears the Sun. Present predictions have the comet reaching +4 th magnitude, and it may flirt with naked eye brightness. The comet passes simply 0.233 AU (21.7 million miles or 34.9 million kilometers) from the Earth on December 12th, another plus.
Often, dynamically new comets display a burst of activity as they approach the inner solar system for the very first time, heat up, and sublimate their external layers. A comet such as A1 Leonard has actually endured a perihelion passage previously without disintegrating … though this one will be its last.
Getting brighter … Comet A1 Leonard from November 13th. Credit and copyright: Hisayoshi Kato.
Presently, A1 Leonard lies high at dawn for northern hemisphere observers in the constellation Canes Venatici, and starts the plunge sunward throughout the very first half of the month. We really cross the plane of the comets orbit on December 8th, and the comet might show a sharp anti-tail spike sunward around this time.
Another intriguing effect may likewise come into play throughout the December phantom of Comet A1 Leonard. The the Sun-Earth-Comet phase-angle for the tail will sit at higher than 120 degrees from December 9th to December 22nd, and reach an optimum of 160 degrees on December 14th just after it passes closest to the Earth on December 12th. This sets up conditions perfect for a possible surge in brightness, adding the brightness of the tail to the coma of the comet itself.
Comet A1 Leonard from October 30th. Image credit and copyright: Zlatko Orbanic.
Its always difficult to know exactly what comets will do. The planet Venus really travels through the tail of Comet A1 Leonard on December 19th, perhaps developing a Venusian meteor shower in the procedure. Presently, only JAXAs Akatsuki objective in on-hand and active in orbit around Venus.
Unfortunately, the night apparition for Comet A1 Leonard will be a bashful one after it flips from early morning to the sunset sky around December 15th. For northern hemisphere observers the comet stays low in the dusk. Southern hemisphere audiences will, nevertheless, get a much better deem the comet fades, declining in the instructions of the constellation of Piscis Austrinus in early 2022.
The celestial path of Comet A1 Leonard in December 2021. Credit: Starry Night
Here are some key celestial dates with destiny for Comet A1 Leonard (keep in mind close suggests within a degree, unless otherwise shown):.
November.
28-Crosses into Coma Berenices.
The dawn path of the comet in early December. Credit: Starry Night.
December.
1-Crosses into Canes Venatici.
3-Photo op: passes extremely near the globular cluster Messier 3.
4-Crosses into Boötes.
6-Passes 4 degrees from the bright star Arcturus.
8-Orbit edge-on as seen from Earth.
9-Crosses into Serpens Caput.
10-Crosses into Hercules.
11-Crosses into Ophiuchus.
12-Crosses the celestial equator southward, and passes 0.233 AU (34.9 million km) from the Earth, moving half a degree (the period of a Full Moon) per hour.
13-Flips over from the early morning to evening sky, and might top out at +4 th magnitude.
14-Passes near +3.3 magnitude star Nu Ophiuchi, and into Serpens Cauda.
14-Transits Messier 16, and passes 15 degrees from the Sun.
15-Crosses the stellar plane southward.
15-Briefly crosses into Scutum, passes near comet 252P LINEAR, passes 1.5 degrees from Messier 17, and crosses into Sagittarius.
16-Passes near the stars: +3.5 magnitude Xi ^ 2 Sagittarii, +3.8 Omicron Sagittarii and +2.8 Albaldah, and crosses the ecliptic southward.
17-Passes 5 degrees from Venus.
18-Passes simply 0.028 AU (4.2 million km) from Venus.
21-Crosses into Microscopium.
30-Passes into Piscis Austrinus.
The dusk view of Comet A1 Leonard for the last half of December, as seem from South Africa. Credit: Starry Night.
January.
3-Reaches perihelion at 0.62 AU from the Sun.
February.
1-Drops pull back listed below +10 th magnitude.
As you can see, mid-December is a hectic one for Comet A1 Leonard, as it nears the busy stellar airplane.
The light curve of Comet A1 Leonard, with observations (black dots) versus perihelion (purple line). Adapted from Seiichi Yoshidas Weekly Information About Bright Comets.
If Comet A1 Leonard over-performs and breaks into naked eye territory, things might get really interesting. Like Comet F3 NEOWISE, A1 Leonard would then have the prospective to posture with foreground things in the dawn, making for a really photogenic comet.
Strategy on braving the morning December cold to catch sight of Comet A1 Leonard at dawn.
Lead image credit: Comet A1 Leonard near the galaxy NGC 4395 in mid-November. Credit and copyright: Michael Jäger.
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On the night of January 3rd, precisely one year to the day prior to perihelion, astronomer Gregory J. Leonard working at the Mount Lemmon Observatory near Tucson Arizona discovered the first long-period comet of the year, C/2021 A1 Leonard. Another interesting impact might likewise come into play during the December phantom of Comet A1 Leonard. The world Venus really passes through the tail of Comet A1 Leonard on December 19th, possibly creating a Venusian meteor shower in the process. The evening apparition for Comet A1 Leonard will be a bashful one after it turns from early morning to the sunset sky around December 15th. Like Comet F3 NEOWISE, A1 Leonard would then have the potential to position with foreground things in the dawn, making for a genuinely photogenic comet.

Now is the time to begin tracking Comet C/2021 A1 Leonard, as it begins its dawn dive sunward.
The days following New Years 2021 saw a comet discovery with capacity. On the night of January 3rd, precisely one year to the day prior to perihelion, astronomer Gregory J. Leonard operating at the Mount Lemmon Observatory near Tucson Arizona discovered the first long-period comet of the year, C/2021 A1 Leonard. Shining at magnitude +19 and 5 Astronomical Units (AU) far-off (about the distance of Jupiter from the Sun) at the time of discovery, early signs hinted that comet A1 Leonard might prove to be something unique, come the end of 2021.