But many amateur astronomers and skywatchers around the world are patiently \u2013 or impatiently! \u2013 waiting for summer to end and autumn to begin.<\/p>
Because that\u2019s when we might have a bright comet<\/a> in our sky.<\/p> Soon after it was discovered in January of last year, studies of the orbit of Comet C\/2023 A3 (Tsuchinshan-ATLAS)<\/a> suggested it could become very bright in the evening sky in October 2024.<\/p> It may even become as bright as zero magnitude, the reports said.<\/p> That would make it the brightest comet to grace our northern sky for many years.<\/p> Since then the comet has been observed and photographed regularly, as it moved slowly through Virgo and into neighbouring Leo.<\/p> It has developed a short, curved tail, and although it hadn’t brightened as much or as quickly as expected or predicted, the general optimism was it was still going to be a naked-eye object in October\u2019s evening sky, after rounding the Sun.<\/p> The optimism surrounding Comet C\/2023 A3 was somewhat was dampened \u2013 if not drowned – at the start of July by scientific paper entitled ‘Inevitable Endgame of Comet Tsuchinshan-ATLAS (C\/2023 A3)<\/strong>‘ predicting the future for A3 is looking very bleak indeed.<\/p> The paper, written by respected comet expert Zdenek Sekanina, suggests the aforementioned failure of A3 to brighten as predicted means the comet might be in the process of disintegrating.<\/p> It might even have disintegrated already.<\/p> Inevitably, for the next couple of days there was much wailing and gnashing of teeth in the comet community.<\/p> When the paper\u2019s contents were picked up by astronomy and science websites, word began to spread across social media that Comet A3 was ‘doomed’ and that the proverbial big show in October had been cancelled, with no hope of refunds for the skywatchers who had bought early tickets.<\/p> Here’s the abstract from the beginning of the paper:<\/p> Hopes are being widely expressed that C\/2023 A3 could become a naked-eye object about the time of its perihelion passage in late 2024. However, based on its past and current performance, the comet is expected to disintegrate before reaching perihelion. Independent lines of evidence point to its forth-coming inevitable collapse.<\/em><\/p> The first issue, which was recently called attention to by I. Ferrin, is this Oort cloud comet\u2019s failure to brighten at a heliocentric distance exceeding 2 AU, about 160 days pre-perihelion, accompanied by a sharp drop in the production of dust (Af_). Apparent over a longer period of time, but largely ignored, has been the barycentric original semimajor axis inching toward negative numbers and the mean residual increasing after the light-curve anomaly, suggesting a fragmented nucleus whose motion is being affected by a nongravitational acceleration; and an unusually narrow, teardrop dust tail with its peculiar orientation, implying copious emission of large grains far from the Sun but no microscopic dust recently.<\/em><\/p> This evidence suggests that the comet has entered an advanced phase of fragmentation, in which increasing numbers of dry, fractured refractory solids stay assembled in dark, porous blobs of exotic shape, becoming undetectable as they gradually disperse in space.<\/em><\/p> You can read the paper here: https:\/\/arxiv.org\/abs\/2407.06166<\/a><\/p> As you can see, that was very gloomy reading indeed. But some are arguing that reports of the death of Comet A3 have been exaggerated.<\/p> In the aftermath of the paper\u2019s publication, other<\/em> comet experts raised their hands and said “Hang on, that doesn\u2019t seem right\u2026”<\/p> They argued that the comet\u2019s stalled brightening could be explained by other things, such as the angle at which we\u2019re seeing it from Earth at the moment.<\/p> They also pointed out that images of the comet show no sign of any disintegration, no clumps of material falling away from it or moving down its tail etc., which we usually see during the disintegration of a comet.<\/p> Indeed, images of A3 by comet photographer Gerald Rhemann<\/a> at the start of July, under the famously dark skies of Farm Tivoli in Namibia, show A3 has developed a short but noticeable ion tail, suggesting the comet nucleus is healthy and not falling apart.<\/p> And the below image was captured by Jos\u00e9 J. Chambo, another prolific comet photographer, from Namibia at the end of June 2024.<\/p> As you can imagine there is now a lot of discussion in the comet-observing community, with some groaning \u201cI told you so!! It\u2019s another Kohoutek\/ISON! This always happens!\u201d<\/p> Other grizzled veterans, who have been here many times before, are sighing \u201cCalm down everyone, it\u2019s looking ok\u2026\u201d<\/p> Some are even suggesting the comet is still on track to become a naked-eye object in October, with a peak brightness of zero or even negative magnitude.<\/p> So, what\u2019s the truth? Is Comet A3 falling apart like a clown car, as other promising comets have done in the past, and all we\u2019ll see of it after it rounds the Sun will be a faint, dusty trail?<\/p> Or is it still doing just fine, out there between Mars and Jupiter, as it closes in on the Sun?<\/p> The answer, as ever, is \u201cWe\u2019ll just have to wait and see\u201d!<\/p> Predicting the behaviour of comets is famously and notoriously hard.<\/p> Comets we thought were going to be bright have fizzled out and left us shaking our fists at the sky in frustration.<\/p>The hype around Comet C\/2023 A3<\/strong><\/h2>
![\"Chart](\"https:\/\/c02.purpledshub.com\/uploads\/sites\/48\/2024\/05\/Comet-A3-june-2024-1024x816.jpg?fit=800%2C638\")
Is Comet C\/2023 A3 doomed?<\/strong><\/h2>
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The Comet A3 paper<\/strong><\/h2>
![\"Comet](\"https:\/\/c02.purpledshub.com\/uploads\/sites\/48\/2024\/05\/c-2023-a3-tsuchinshan-atlas-social-1024x538.jpg?fit=800%2C420\")
Comet C\/2023 A3: a new hope?<\/strong><\/h2>
![\"Comet](\"https:\/\/c02.purpledshub.com\/uploads\/sites\/48\/2024\/07\/comet-c2023-a3-june-2024-1024x768.jpg?fit=800%2C600\")
![\"Comet](\"https:\/\/c02.purpledshub.com\/uploads\/sites\/48\/2021\/09\/Comet-ISON-C2012-S1-soho-cfdb3fd.jpeg\")