This story may give you a sense of déjà vu.
A new comet has been discovered, and in late May it will pass by the sun near the orbit of Mercury. But it’s not Comet ATLAS (C/2019 Y4). Instead, this is Comet SWAN (C/2020 F8)
The above awesome 5 minute exposure picture was captured on April 13th.
The new very brilliant comet was discovered by Michael Mattiazzo of Swan Hill, Victoria, Australia, on April 11, 2020, when he was looking at data from the Solar and Heliospheric Observatory’s (SOHO) SWAN instrument.
This is his 8th discovery credit for SWAN comets since 2004.
Ernest Guido and colleagues confirm that the comet is bright (8th magnitude), green, and has a long tail as shown in the picture below.
Guido explains: “We took this picture on April 11th – the same day Mattiazzo found the comet in SWAN data. We couldn’t see it from Italy, so we used a remote-controlled 0.1 meter telescope in Australia.“
SOHO’s Swan Instrument
SOHO’s SWAN instrument was not designed to find comets. Its job is to survey the solar system for hydrogen.
When the solar wind blows into a cloud of hydrogen-bearing compounds, the impact produces UV photons that SWAN can photograph.
“For SWAN to see a comet, it means the comet must be producing a fairly significant amount of hydrogen,” explains Karl Battams of the Naval Research Lab in Washington DC. “This is usually in the form of water-ice.“
“It’s extremely likely that Comet SWAN is in ‘outburst’ mode,” he continues. “That is, some major eruption happened to this otherwise small and faint comet, releasing a massive cloud of hydrogen-rich volatiles. SWAN is picking up on this sudden dump of hydrogen into the inner solar system.“
Comet SWAN visible to the naked eye next month
If the outburst continues, Comet SWAN could become visible to the naked eye next month.
Preliminary light curves suggest that it could reach 3rd magnitude – dim, but visible without optics.
However, Battams, who correctly predicted the demise of Comet ATLAS, is not so sure.
“I doubt that the comet will maintain its current impressive appearance, and will quite possibly fade away soon,” he says. “But we’ve only been viewing it for a couple of days, so no one knows.”
Comet SWAN is currently located in southern skies, best seen by telescopes in Australia, New Zealand, southern Africa and South America. Preliminary orbital elements are available here.
Keep your eyes to the sky and enjoy this new Comet SWAN and some more sky events like the following April’s meteor showers.