As it makes its death-defying dive toward the sun, Comet Pan-STARRS is dazzling the inner solar system. The sungrazing comet, that became a Northern Hemisphere celestial object over the weekend, is now within the field of view of one of NASA’s solar observatories. And it’s bright.
The Solar TErrestrial RElations Observatory (STEREO) is comprised of two sun-orbiting telescopes on opposite sides of our nearest star. The mission’s primary function is to take observations of the sun’s atmosphere from two vantage points, providing a detailed perspective on space weather phenomena, such as coronal mass ejections and the solar wind.
But comets often make an appearance too, as they ‘play chicken’ with the sun’s superheated plasma.
“Comet Pan-STARRS is so bright, it is actually saturating the pixels of the imager’s digital camera,” said NASA’s Tony Phillips, curator of Spaceweather.com. “The comet’s luminosity is mainly due to dust. Earth-based observations show that Pan-STARRS is dustier than an average comet. Comet dust reflects sunlight, so the fan-shaped tail of Pan-STARRS, chock full of it, is especially bright.”
As can be seen from the observation above (made by STEREO-B), the saturation of the observatory’s pixels is obvious — the triangular shape at the bottom is Comet Pan-STARRS, the dot to the right is us (Earth) and the sun is to the left.
Pan-STARRS will come within 28 million miles (45 million kilometers) of the solar photosphere before the sun slingshots it back out into deep space. It’s thought the comet originated from a mysterious, frozen region of the solar system, around a light-year from the sun. This hypothetical region is known as the Oort Cloud, a place where countless billions of comet nuclei swarm. Occasionally, these pristine “dirty snowballs” get disturbed and fall toward the sun only to end their epic journey getting eaten by the sun, or, in the case of Pan-STARRS, swing past, narrowly avoiding solar incineration.
Image credit: NASA