prossimi comete visibili italia

Next comets potentially visible in Italy: watch out for the “Halloween comet” C/2024 S1

The “comet of the century” C/2023 A3 (Tsuchinshan-ATLAS) is still putting on a show high on the south-west horizon for three hours after sunset, visible through binoculars. As the days go by it is becoming weaker and weaker, saying goodbye definitively towards the end of October. If the show hasn’t quenched your hunger for hairy celestial bodies, here’s what they will potentially brighter comets of the next three monthsbetween 2024 and 2025.

The most interesting opportunity comes from the one that has already been renamed “Halloween Comet” o C/2024 S1 (ATLAS), discovered only in recent weeks, which belongs to the family of “Kreutz’s grazing comets” (Kreutz sungazer) as the October 28, 2024 it will reach perihelion on its own 1.2 million km from the Sun. If the comet survives this reckless dive into the solar corona, it could become visible to the naked eye between the end of October and the beginning of November with a brightness comparable to that of the star Sirius, which is the brightest star in the firmament. A similar brightness could also be achieved by comet C/2024 G3 (ATLAS)which will pass to the point of maximum proximity to the Sun on January 13, 2025alone 14 million km from the solar surface.

However, let us remember that Comets are very unpredictable objectstherefore any anticipation (especially regarding their visibility) must be taken with due pinch of salt.

Comets potentially visible in Italy in the coming months

There comet C/2024 S1 (ATLAS) has earned the title of “Halloween Comet”since the perihelion (point of maximum proximity to the Sun) will occur on October 28, 2024close to the Halloween holiday, while the point of maximum proximity to the Earth was Wednesday 23 October. The Halloween comet is part of the category of comets sungrazera class of “reckless” comets whose orbit brings them extremely close to the Sun. C/2024 S1 (ATLAS), in particular, will pass perihelion at just 1.2 million km from the solar surface, literally crossing the outermost part of the solar corona.

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Image of the “Halloween comet” obtained on September 28, 2024. Credit: Exoplanetaryscience, CC BY 4.0, via Wikimedia Commons

However, this reckless life has a cost: comets sungrazer they tend to disintegrate even before reaching perihelion. However, if they survive, they can become extremely bright, as was the case with comet Lovejoy in 2011. We don’t know for sure whether C/2024 S1 (ATLAS) has already started to disintegrate, but a report dated October 9th published on The Astronomer’s Telegramcontaining images obtained with the telescopes of the South African Astronomical Observatory, shows how the comet presents i first signs of the disintegration process.

Currently, the Halloween comet has a magnitude equal to approximately 8therefore invisible to the naked eye but detectable with a good telescope. However, its small angular distance from the Sun makes it nearly impossible to locate in the dawn glow. The comet is gradually increasing in brightness as perihelion approaches and the projections, in case of survival, report it as a possible comet of magnitude –1about as bright as Sirius. After closest approach, the comet will increase its angular distance from the Sun again, potentially becoming visible, low on the south-east horizonabout an hour before sunrise.

Comet C/2024 G3 (ATLAS)

There comet C/2024 G3 (ATLAS) it was discovered on 5 April 2024 by the ATLAS project, the same with which the “Halloween comet” and the “comet of the century” C/2023 A3 were discovered. Judging by its orbit, it could be one comet on first pass in the inner Solar System. C/2024 G3 (ATLAS) is part of the class of comets sunskirterthat is, those objects that pass within 33 solar radii of the center of the Sun (i.e. about 23 million km, less than half the distance between the Sun and the planet Mercury).

The comet currently has a magnitude equal to 12therefore not visible only through telescopes with a generous diameter. However, the comet is gaining in brightness day by day as it approaches perihelion, which is forecast for January 13, 2025. The projections report that the comet, if it survives the close encounter with our star, will well exceed the threshold of visibility with the naked eye, reaching a value of magnitude equal to –1about as bright as Sirius.

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Schematic representation of the orbital path of comet C/2024 G3. Credits: http://astro.vanbuitenen.nl/comet/2024G3

At perihelion on January 13, the comet will be angularly very close to the Sun, so it will be difficult to observe in the south-east in the light of dawn. Moving away from the perihelion, although the angular distance from the Sun increases, the visibility of the object from Italy it will not improve much, since the comet’s orbital configuration will make it more easily observable at sunset for those located in the southern hemisphere.

The other comets approaching in 2024 potentially visible from Italy

We close the list of comets arriving in the next three months with comets 333P/LINEAR, C/2022 E2 (ATLAS), C/2024 B1 (Lemmon) and C/2024 M1 (ATLAS). These comets they are not particularly bright and represent a real challenge for amateur astronomers. All four currently have one magnitude that varies between 13 and 15therefore observable only through telescopes with generous apertures.

C/2024 B1 (Lemmon) it passed perihelion on October 7, 2024 at a distance of approximately 245 million km from the Sun (approximately the Mars-Sun distance to the planet’s aphelion), while C/2022 E2 (ATLAS) The September 14th at a distance approximately halfway between Mars and Jupiter. C/2024 M1 (ATLAS) will pass to perihelion November 20, 2024 at a distance of approximately 255 million kmWhile 333P/LINEAR will reach the minimum distance from the Sun of 166 million km The November 29, 2024.