Naked-eye comet on the horizon: Tsuchinshan-ATLAS grows brighter

Naked-eye comet on the horizon: Tsuchinshan-ATLAS grows brighter

The “comet of the year” is getting brighter. In the wake of the total solar eclipse and the sudden solar “superstorms,” it’s looking more likely that we’ll also see a naked-eye comet later this year in the evening skies.

Comet Tsuchinshan-ATLAS (C/2023 A3) is now getting brighter and growing a tail, according to Sky and Telescope, writes.

Traveling between the orbits of Mars and Jupiter, for now, comet A3 is only observable in a large telescope. It’s in the constellation Virgo.

Comets visible to the naked eye are notoriously difficult to predict in advance, but this one is expected to brighten substantially during October and possibly become as bright as Venus in the night sky. That would make it the “comet of the year”—and possibly the century.Where Is The Comet?

Arriving in the wake of the so-called “eclipse comet” 12P/Pons–Brooks, 2023’s "green comet" and 2020’s comet NEOWISE, this particular cosmic snowball is a long-period comet with an orbit of just over 80,000 years. It comes from the Oort Cloud—a sphere around our solar system that’s home to millions of comets.

Comet A3 was discovered in February 2023 by astronomers at both South Africa’s Asteroid Terrestrial-impact Last Alert System (ATLAS) telescope and China’s Tsuchinshan Observatory.

When And Where To See The Comet

The comet’s perihelion—its closest approach to the sun—will occur on October 10, 2024. From the northern hemisphere, it will be easiest to see the comet just after that, when it will be visible in the southwest just after sunset.

It’s hoped the comet will be a naked-eye object in the southern sky, climbing higher into the sky during October and November.

How Bright Will The Comet Be?

It’s impossible to know in advance, but it could get as bright as Venus, roughly magnitude -5. Venus is the second brightest object in the night sky after the full moon at a magnitude of -12.6. It’s the geometry of this comet’s position relative to Earth that might make that possible.

Even if it does get that bright, we’re unlikely to get much benefit because, at its brightest, it will be very low on the horizon and lost in its haze, as seen from the northern hemisphere.