Big comet?

In a series of difficult recent years, the current 2020 is perceived as completely exceptional: in addition to local revolutions, riots and coupling, an unprecedented pandemic seized the entire globe. Of course, such a year could not do without the "caustic messenger of misfortunes":

Now, here is the “Big Comet of 2020” almost irrevocably leaves us (will return only after 7 thousand years; its aphietces - at 500–700 A.E. from the Sun). Let's hope - taking away with yourself and embarrassment in the minds. It remains only to observe its most spectacular photos. The comet passed its perihelium on July 3 very close to the sun (at 0.29 A.E.). Then she had a second tail, and if the first - bluish ion - glowed due to the fluorescence of molecules C2 and CN (a small sodium component was also found in it - with the help of NASA Parker Solar Sunday), the second - golden and smaller - consisted of dust tearing under the influence of close sun.

The comet is removed from us at a speed of more than 60 km/s, but on August 8, the Khabble space telescope (when the comet turned away from the sun) managed to finally take the most detailed from all available pictures, on which you can consider the so -called dusty membrane surrounding a more dense core (unfortunately, the core itself cannot be distinguished).

In the press releases [1, 2] it is noted that the observation of the Hubble comet Neowise is the first time when the object of such brightness is photographed with high resolution after rapprochement with the sun. Previous attempts to capture other bright comets (for example, the ATLAS comet) were unsuccessful due to the actual collapse of such objects after a too close approach to our luminary. Comets, as a rule, break up due to thermal and gravitational influences with similar rapprocheces, but this time the Hubble showed that the solid icy nucleus of Neowise survived. The size of the nucleus should not exceed 4.8 km, and we can only consider the cloud of gas and dust surrounding it with a diane of about 18 thousand km.

Should the current comet be considered truly outstanding? “Big/Great Comets” are relatively rare: over a decade, only one similar appears on average. The vast majority of comets are not bright enough to distinguish them without binoculars and telescopes, usually they pass through the inside of the solar system only under the eyes of astronomers. And the media give out formulations leading to all kinds of confusion. So, it must be taken into account that in the Northern Hemisphere in the XXI century C/2020 F3-it is really the brightest comet, but, as mentioned above, in the South there was still something more interesting. In addition to the McNot comet, C/2011 W3 (Lavjoy) is mentioned - “The Great Comet of Christmas 2011” (The Great Christmas Comet of 2011). Yes, and those who remember the comet Hale-Boppa (a large comet of 1997), who shone in our heavens an absolutely record 18 months (in fact, it was visible since 1996), which led to the mass suicide of some sectarians, and “interrupted” the large comet of 1996 from/1996 b2 (Hyakuaka), it seems, it seems, it was likely Disappointed. Meanwhile, the macnot comet in some ways surpassed this couple, and the greatest comet of the 20th century should be considered more likely a large comet of 1965 C/1965 S1 (Ikei-Sekki). At the time of the passage of Perigelia, that comet had a stellar value of –17m (that is, it was clearly visible in the daytime sky near the Sun - this is 60 times brighter than the full moon).

In the 19th century, one of the most famous comets was the one that Lev Tolstoy wrote about in the War and the World, a large comet of 1811 (C/1811 F1), which was closing the Patriotic War of 1812 and observed with the naked eye in the sky, a record at that time for 290 days. However, by brightness, several more comets could compare with it. For example, the large September comet of 1882 (C/1882 R1). For some time this comet was also observed in the light of day ...

Unfortunately, it was quite difficult to judge on the basis of oral evidence of which of the cometes observed in the “dofeographic” era is quite difficult. Yes, and modern comets are sometimes difficult to compare. After all, record holders are long structures with variable brightness. Human impressions of the shaking and subjective, the circumstances of the observations change - the sky may not be dark or not clear enough ... If we talk about the unofficial epithet “big” or “great”, which is applied to a particular comet (of course, at least visible to the naked eye and in terms of brightness comparable to the most bright stars), of course, of course, does not always reflect the true propagation Phenomena. Indeed, in addition to the proximity to the Earth, the brightness of a comet is determined by the size and activity of the nucleus (and the cores of the comet are varying from a few hundred meters - and less - to many kilometers) and also the arrangement of perihelia. The brightness of a simple reflective body depends on the reverse square of its remoteness from the sun. If the distance from the object to the luminary is halved, its brightness increases four times. However, comets behave differently due to the release of a large number of volatile gases, which also reflect sunlight and can fluorescence. Their brightness changes approximately like a reverse cube of the distance from the sun, which means that if the distance from the comet to the sun decreases by half, then the comet will become eight times brighter. Say, the most famous bright (and actually the only such) Galley’s short-period comet, returning to the Sun every 75–76 years, last time (in 1986), she pretty much disappointed her fans, remaining barely distinguishable without a telescope (however, this did not prevent her from conducting very active research with the help of several space apparatuses at once (Soviet Vega-1 and Vega-2, As well as the European “Giotto” and Japanese probes), which transmitted data on the structure of the cometary nucleus and the mechanisms of the formation of comet and the tail of the comet.

Sometimes a comet, the victim failure according to one criterion, still leaves a long memory of itself. So, the comet Hale - Boppa could boast of an exceptionally large and active core, and even if she did not approach the sun close enough, still became an extremely famous and most observed comet (well, partly also thanks to the Internet and considerable noise in the press). In the same way, the Komet Hyakite - in fact, not a very big comet - looked very bright, because it turned out to be very close to the ground. The current comet, too, will certainly be remembered, but cannot be compared with these predecessors.

Maxim Borisov