Observations de la comète Leonard... vues de l'espace

Three different space missions offer spectacular views of Christmas Comet A1 Leonard.

Comet A1 Leonard, as seen from (left to right): from Yangwang-1, Solar Orbiter, and STEREO-A. Credit: CNSA, ESA, NASA.

If you’re like us, you’ve been amazed by some of the views we’ve had of Comet C/2021 A1 Leonard worldwide leading up to this Christmas season 2021. Now, check out these stellar views of the comet from space.

First up, is the view courtesy of the European Space Agency’s Solar Orbiter (SolO) mission. The capture was made by the Solar Heliospheric Imager (SoloHI) instrument from December 17 to the 19th, and shows the comet (along with the planets Mercury and Venus) sliding through the field of view:

The geometry of the view places the inbound comet with the dust tail off to one side, but also illustrates an intriguing aspect of comets: the dust tail is driven by the solar wind, meaning that it always points away from the Sun. Right now, the comet is beginning its U-turn through the inner solar system, meaning that after it passes perihelion at 0.62 AU (92.8 million kilometers) from the Sun on January 3^rd, 2022, the tail will lead the comet on its outbound leg.

Next up are views from NASA’s STEREO-A (The Solar TErrestrial RElatiOns) spacecraft:

So yeah, comet Leonard has definitely kicked into a new gear over the past couple of days. Check out that tail action! ?

These are highly-processed images from our @USNRL SECCHI/HI-2 camera @NASASun STEREO-A on Dec 14.

?: B.Gallagher, NRL> pic.twitter.com/QzNWL2UjNf

— Karl Battams (@SungrazerComets) December 16, 2021

This enhanced view was captured on December 14^th courtesy of STEREO-A’s SECCHI/HI-2 camera, and subtracts ‘difference images’ from one frame to the other to bring out subtle contrast in the comet’s wispy tail. STEREO-A and the late STEREO-B spacecraft (which failed in 2014) observe the Sun from separate vantage points in the solar system, and comets do occasionally ‘photo-bomb’ its field of view.

…and finally, here’s the view from a Chinese space telescope Yangwang-1: Never heard of Yangwang-1? This small proof of concept mission was launched on a Long March-2D rocket in early November 2021, and sports a small primary mirror. Yangwang-1 (meaning ‘look up’ in Chinese) caught ‘comet-rise’ around the limb of the Earth from its vantage point in Earth orbit, with a slight halo of high-altitude aurora adding in a very photogenic touch to the scene:

Now’s the time to see the comet, while you still can. Discovered on the night of January 3^rd 2021 precisely one year before perihelion by Gregory J. Leonard as part of the Mount Lemmon Catalina Sky Survey, A1 Leonard was a fine binocular comet at dawn in early December for northern hemisphere observers. The comet is brightening now at magnitude +4.5 as it heads towards perihelion next week, and is currently crossing the constellation Microscopium and is now well-placed for southern hemisphere observers at dusk.

Comet Leonard also sustained a tail disconnection event over the past weekend, suggesting that it is still very much dynamically active as it nears the heat of the Sun towards perihelion.

The comet is on an ~80,000 year orbit inbound, but won’t be returning to the solar system again, as passages near Earth and Venus in 2021 tweaked its orbit enough to kick it out of the solar system post-perihelion. After 2022, the comet will instead wander the galaxy as an interstellar object.

Don’t miss your last chance to see Comet A1 Leonard, as we marvel at these amazing views of the comet from space.