If you have access to some binoculars, you can spot something special in the night sky, particularly on Friday, February 15, in the constellation Cancer: the comet known as C/2018 Y1 Iwamoto.
The recently discovered comet is being described as a shimmering, green object from Earth’s perspective, with a classification as an Extreme Trans-Neptunian object locked into a wildly eccentric orbit. It is already visible through telescopes and binoculars, and it’s set to reach a prominent point of visibility on Friday.
This is the first binocular comet of 2019, and that is defined as a comet that can be seen from our perspective with simple binoculars, to state the obvious. Only a few binocular comets seem to come every year.
With the discovery being attributed to Masayuki Iwamoto, an amateur astronomer, a few other interesting details people may not be familiar with can be derived from this information.
For instance, this comet has been calculated to orbit the Sun in an extremely elongated, 1,371-year orbit. It sort of adds intensity to the reality of comets to know that they whirl around the Sun, sometimes with multi-millennial orbital periods.
Some objects that bear resemblance to this green comet approach Earth much closer, but this one is going to get as close as 28 million miles (45 million kilometers). For some perspective, that’s about 118 times further from Earth than the Moon.
Reminiscent of the way copper burns green, it is being said that some comets typically emit a green glow due to exactly what anybody would expect, a nondescript composition of gas and dust, released by melting ice, forming what is referred to as a “comet coma.”
When the human eye spots the comet, it sees the effect of ultraviolet light in space hitting the ball of volatile ice and material that composes the comet, causing it to appear green. However, a fairly vague description of a green comet’s actual composition was provided. In 2018, a comet was so visibly green it was dubbed “the Incredible Hulk.”
At this link, you can find a tool that is useful for spotting exactly where in the sky C/2018 Y1 Iwamoto is located. If you acquire a telescope or even some simple binoculars, you can look up in the sky at the constellation Cancer, and spot it for the next few days.
Thankfully, the constellation Cancer is prominently visible in the sky right now, as the Sun in Aquarius (Capricorn sidereal) is nearly opposite it. South of Cancer in the sky, you can spot the brightest star in the night sky: Sirius, in the constellation Canis Majoris. The bright star Sirius is a helpful point of reference to locate this green comet.
One interesting thing about this comet is the fact that it is happening to transverse the sky closest to Earth, right along some of the zodiac constellations. Of all spots to appear in the sky from Earth’s perspective, it will hit the zodiac belt constellations of Leo, Cancer, and Gemini, going a little bit backwards through the ecliptic before it returns to the end of our Solar System.
The “comet” has such an eccentric orbit, it’s small but it is seemingly unusual that it technically qualifies as an Extreme Trans-Neptunian Object, like a Sednoid if you’re familiar with the term.
This is the last time we’ll get to lay eyes upon C/2018 Y1 Iwamoto, so unless you expect to live until the year 3390, you can go get some binoculars and invite someone to spot the comet with you if you want to make the most of it.