UPDATE LEONARD COMET

 Comet Leonard quickly loses brightness, based on the latest visual observations of this comet, its latest report, is located at visual magnitude m1 = + 4.8, this means a rapid decrease in its rate of increase in brightness, and therefore in its gaseous and dusty activity, according to my calculation at a rate of 0.44 magnitudes per day, this is an excessive rate of decrease in brightness, after the burst of brightness, which took place a few days ago, specifically on December 14, Today the 19th, that is, 5 days later, the comet has lost 2.6 magnitudes, let's bear in mind that a jump of one magnitude is equivalent to a difference in brightness of 2.5 times (the fifth root of 100), so The comet in just 5 days, has varied approximately 6 times its difference in brightness, we can conclude that its period of visibility with the naked eye has been very short, according to my data, little more than a week ... however, it is still right now as bright as the comet 1 P / Halley in its appearance in 1986, I encourage all of you to keep trying to observe it, now that it is still relatively bright, remember, that it is already difficult to see comets of magnitude 5 as it is right now. Graphic : COBS .
https://fb.watch/9_SXErxymp/

Images of comet C/2021 A1 LEONARD .

 Images of comet C/2021 A1 LEONARD .

LARSON SEKANINA FILTER LEONARD COMET

 Good morning before the doubts that this comet is offering, and the rumor that runs that it is disintegrating, I have used the larson sekanina filter, this filter calculates the radial and rotational gradient of an image. It is used to enhance the finest details in bright objects, exhibiting symmetry of revolution (elliptical galaxies and comet commas). This filter is very powerful to reveal internal details within the coma of bright comets (such as jets and shells), in the attached image not a single fragmentation detail is observed, only the ionic tail, in addition to that I have done to ensure even more, a GDP of the coma, in which there is no abrupt or strange change in it.

Image Credit: Pepe Manteca.

Processed: J.P. Navarro Pina.

Dall-Kirkham Telescope 0.43 mts.

Cometary blackout in Leonard's Comet

 I have a hypothesis that I have been studying for years for these

cases, when a comet suffers a fading of the rate of increase in
brightness, and that is that the comet suffers a change in the

predominant volatile component CO -> H2O, this is usually typical in
the new comets coming from the Oort cloud, this slowdown in its
activity index, usually occurs in the heliocentric range of 1.5 <R
1.2, as is the case of comet C / 2021 A1 LEONARD, I do not think it
will increase much plus its brightness, since my last analysis
indicates an index n = 2.24, the term 2.5 n log R, represents the
change in brightness due to the variation of the heliocentric distance
of the comet, and the brightness varies by pure reflection n = 2, as a
solid object without gaseous activity, which I call the '' cometary
blackout '' .

Graphic adapted by COBS , Analysis J.P.Navarro .

NO FRAGMENTATION COMET 2021 A1 LEONARD

 I have just carried out an analysis of the brightness intensity profile of the coma of comet C / 2021 A1 LEONARD, and no apparent rupture or fragmentation is observed at the coma level, we await more observations that can confirm this fact .
Image Credit : Pepe Manteca
Processed : J.P.Navarro Pina

Comet C / 2021 A1 LEONARD could be visible to the naked eye by Christmas 2021.

 After a last update of the light curve of Comet Leonard, and using only visual observations, it seems that, if there are no surprises, the comet could be visible to the naked eye, my last estimate indicates a probable maximum visual magnitude of m1 = + 4.6 for the date of December 11, 2021, until reaching its perihelion in January 2022, its rate of increase in brightness is quite low, Law Power R ^ -1.7, and n = 4.46, but it is usual for new comets coming from The Oort Cloud, I attach the light curve, but beware, this curve mixes ccd and visual, it is important to differentiate both types of observations, since the difference is usually 1.5 magnitudes, according to a personal study, in this regard, Using the heliocentric and geocentric distances, based on the classic brightness formula for comets, using logarithms for the comet-earth and comet-sun geometry, it could give us a visual magnitude close to +5 and perhaps +4, everything will depend of the act ivity that the comet demonstrates in the determining moments of its proximity to the sun:

m1 = + 8.2 +5 log (D) +4.46 log (R)

This formula is far from the one calculated based on the CCD + VISUAL data, which based on 842 observations would look like this:

m1 = + 11.7 +5 log (D) +5.59 log (R)

The contribution of dust + gas is added in the case of this last formula, we take into account that the spectral response ccd for comets is similar to the amount of dust dispersed and emitted by sunlight, and unlike visual observations, where we observe the swan and C2 bands, and the sum of OH, indicating a small portion of the gas emitted, this leads us to the conclusion that there is more gaseous emission in Comet Leonard than dust.

Update Analysis Light Curve C/2021 A1 LEONARD A1

 My second analysis of the light curve of comet C / 2021 A1 LEONARD, indicates in T-300, a stagnation in the rate of increase in brightness or activity index with a brightness law similar to that of a solid object without gaseous activity. of R ^ (- 1.4), following this same brightness law, its maximum visual magnitude at perihelion could reach m1 = +9.5, in the best of cases.

Also a more exhaustive analysis of the light curve could indicate a probable precession period of the cometary nucleus, with a periodicity of approximately 40 days, due to a sudden increase in brightness or outburst in its light curve around +0.5 at +0.7 magnitudes (+0.7 <dm1 <+0.5) -> P (prec) ~ 40 days.

The estimated general gloss formula is:

m1 = +12.9 +5 log (D) +3.6 log (R)

Based on 525 MPC brightness measurements, and a data residual of +0.52.

Image Credit : J.P.Navarro Light Curve C/2021 A1 LEONARD ( Update 05/09/2021 )

Analysis Light Curve COMET 2021 A1 LEONARD

 Comet C / 2021 A1 Leonard shows at the moment with 272 ccd observations a linear fit in its light curve, the provisional photometric parameters are m0 = + 10. and n = 3.1, this low activity rate shows little gas and dust activity at the nuclear level behaving almost like a solid nucleus with almost no sublimation activity, based on the formula of Sosa & Fdez 2011, the water production rate is 10 ^ 26.42 mol s, I am inclined to think that it is much smaller, like the active fraction area for the nucleus, interpolating data I have taken a value of 0.5 but perhaps it is lower.

Regarding the future brightness trend, green color adjustment, it is observed that the maximum magnitude could be around m1 ~ + 6.0, but these data are CCD, so the apparent or visual magnitude could be much brighter in Based on other analyzed light curves, cautious for now, and wait for the visual observations that will be the ones that will give us more clues in future months of its true maximum brightness.