Comet ATLAS: Will Shine brightest in May or Not?

Astronomers and sky enthusiasts are patiently waiting for the recently discovered comet to grace the sky next month when the comet is at its brightest.

ATLAS, the newly discovered comet is expected to appear in our night skies as one of the brightest comets since Hale-Bopp in 1997. 

The comet, nicknamed in the owner of the Asteroid Terrestrial-impact Last Alert System (ATLAS) telescope. The comet is officially known as C/2019 Y4 and was first spotted in late December 2019. As of mid-late March, it has a magnitude brightness of an eighth-magnitude star. The brightness is not visible yet but within reach of medium-sized telescopes in dark skies.

As the comet nears our solar system and moves to the sun, it becomes brighter. According to Karl Battams of the Naval Research Laboratory in Washington, D.C., the comet is releasing a huge amount of frozen gases which makes it brighten so fast.

ATLAS has brightened to that of an eight-magnitude star since its discovery on December 28, 2019. To measure the object's brightness, apparent magnitude is used. The lower the magnitude reading, the brighter the object appears. Thus, the brightest objects have negative magnitude reading. 

 ATLAS may not be visible to the naked eye, but medium-sized telescopes should be able to spot the new comet in the dark skies. By May, as the newly discovered comet comes closer to the sun, ATLAS may brighten to visible magnitude +1 to -5. 

AS the comet moves towards the sun, frozen volatiles are vaporized on the comet's crust which explains the formation of a glowing coma of gas around the nucleus. The solar wind stretches this into a tail, with some extending for millions of miles from the comet's head.

There are cases in which comets do not vaporize frozen volatiles. Some others, weakened by repeated flybys of the sun, break up and fade away. While ATLAS will brighten the earth by a comfortable 72 million miles on May 23, it is expected that its trajectory will only be 23 million miles of the sun by May 31. Battams doubt if ATLAS will survive such a close encounter. He deems that the comet is over-achieving, and will not be surprised if it will disintegrate before reaching the sun.

But for the stargazing fans, it is not the end of the world. The new comet appears to share an identical 6,000 orbit with the Great Comet of 1844, raising the speculations that the new comet might be a part of the Great Comet.

Comet ATLAS is in a "favorable position for northern latitudes and will appear more than halfway up in the north-northwest sky after nightfall". One should be able to shot it with a telescope through April by looking in the constellation Camelopardalis the Giraffe.

On May 23, it is expected that Comet C/2019 Y4 (ATLAS) will be closest to Earth on May 23. Its perihelion, or the closest distance to the sun, will occur on May 31.

ATLAS is expected to be at 23,517,819 miles (37,848,261 km) from the sun, a distance relatively closer to the sun than Mercury's elliptical orbit (about 36 million miles or 57.9 million km on average).