Martin Mobberley posted a new image of comet 46P/Wirtanen taken remotely from Siding Spring in Australia on October 27, 2018. This image shows a large coma – or cloud around the comet – commonly seen when comets come near the sun. Image via Comets and Asteroids on Facebook.
Have you heard about comet 46P/Wirtanen? It’s approaching the inner solar system, due to pass closest to our sun and Earth in December, 2018. Comet Wirtanen is the brightest comet in the night sky now, although that doesn’t mean you can see it with the eye alone. In fact, it’s visible now only to astronomers with telescopes. But – in December 2018 – comet Wirtanen might be visible to the unaided eye, at least from dark skies. Closest approach to the sun will be December 12, 2018, and closest approach to Earth is just a few days later, on December 16.
According to astronomers at the University of Maryland, this passage of comet Wirtanen near the Earth (near by comet standards, that is) will be the 10th closest approach of a comet in modern times. At its closest to us, the comet will be about 30 times the moon’s distance (7.1 million miles, or 11.5 million km).
Contrast that number to another comet that swept relatively near us recently – 21P/Giacobini-Zinner, which caused a brief outburst in this year’s Draconid meteor shower – and which swept closest to Earth on September 9-10, 2018 at 36 million miles (58 million km). That was the closest Giacobini-Zinner had come in 72 years!
And you can see – from the paragraphs above – that Wirtanen is coming much closer, although still many times the moon’s distance.
This is what’s called a lightcurve. It’s a measurement of comet 46P/Wirtanen’s brightness, over time. The comet is getting brighter! It might become bright enough in December to be viewed with the eye alone, from a dark location. Image via University of Maryland’s comet 46P/Wirtanen: current status page.
Estimates indicate Wirtanen might reach a visual magnitude of 3.5 to 6. That would place the comet clearly in the realm of visibility with the unaided eye (although diffuse objects like comets are tougher to see than the pinpoints of stars at comparable magnitudes).
And, of course, comets have been shown to be unpredictable. We will keep you updated.
Want to stay up-to-date on Wirtanen’s brightness? This webpage from the University of Maryland is providing updates.
The December 16, 2018, close approach to Earth of comet Wirtanen will happen less than 4 days after the comet’s perihelion, or closest point to the sun. Because comets are increasingly active as they draw nearer the sun that binds them in orbit, this comet can be expected to be near its brightest around then. It might be visible to the eye from a dark location. Image via University of Maryland.
Bottom line: Comet Wirtanen will come closest to Earth in December. At that point, it might be visible to the eye alone.
from EarthSky https://ift.tt/2OYXKeL
Martin Mobberley posted a new image of comet 46P/Wirtanen taken remotely from Siding Spring in Australia on October 27, 2018. This image shows a large coma – or cloud around the comet – commonly seen when comets come near the sun. Image via Comets and Asteroids on Facebook.
Have you heard about comet 46P/Wirtanen? It’s approaching the inner solar system, due to pass closest to our sun and Earth in December, 2018. Comet Wirtanen is the brightest comet in the night sky now, although that doesn’t mean you can see it with the eye alone. In fact, it’s visible now only to astronomers with telescopes. But – in December 2018 – comet Wirtanen might be visible to the unaided eye, at least from dark skies. Closest approach to the sun will be December 12, 2018, and closest approach to Earth is just a few days later, on December 16.
According to astronomers at the University of Maryland, this passage of comet Wirtanen near the Earth (near by comet standards, that is) will be the 10th closest approach of a comet in modern times. At its closest to us, the comet will be about 30 times the moon’s distance (7.1 million miles, or 11.5 million km).
Contrast that number to another comet that swept relatively near us recently – 21P/Giacobini-Zinner, which caused a brief outburst in this year’s Draconid meteor shower – and which swept closest to Earth on September 9-10, 2018 at 36 million miles (58 million km). That was the closest Giacobini-Zinner had come in 72 years!
And you can see – from the paragraphs above – that Wirtanen is coming much closer, although still many times the moon’s distance.
This is what’s called a lightcurve. It’s a measurement of comet 46P/Wirtanen’s brightness, over time. The comet is getting brighter! It might become bright enough in December to be viewed with the eye alone, from a dark location. Image via University of Maryland’s comet 46P/Wirtanen: current status page.
Estimates indicate Wirtanen might reach a visual magnitude of 3.5 to 6. That would place the comet clearly in the realm of visibility with the unaided eye (although diffuse objects like comets are tougher to see than the pinpoints of stars at comparable magnitudes).
And, of course, comets have been shown to be unpredictable. We will keep you updated.
Want to stay up-to-date on Wirtanen’s brightness? This webpage from the University of Maryland is providing updates.
The December 16, 2018, close approach to Earth of comet Wirtanen will happen less than 4 days after the comet’s perihelion, or closest point to the sun. Because comets are increasingly active as they draw nearer the sun that binds them in orbit, this comet can be expected to be near its brightest around then. It might be visible to the eye from a dark location. Image via University of Maryland.
Bottom line: Comet Wirtanen will come closest to Earth in December. At that point, it might be visible to the eye alone.
from EarthSky https://ift.tt/2OYXKeL
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