Comet gazers this week are being treated to views of comet “Africano” discovered last year by B.M.Africano at Mt Lemmon and reported merely 21 minutes before the Catalina Sky Survey noticed it too. Africano passed within 0.5 AU (half the distance between the Sun and the Earth) and currently appears to moving towards Neptune in the Northern sky for us Southern Hemisphere viewers.
Like most comets we see, Africano has come from the far reaches of our solar system but is on a peculiar hyperbolic trajectory which means it’s about to be slingshot out and escape the Sun’s gravitational influence forever unless it meets one of the planets on the way out and is captured again. So this is your last chance to see this comet, that we just discovered, ever. It’s fairly large (as far as comets go) and should be easily photographed even with modest telescopes. Pictured here taken with the 400mm focal length Celestron RASA 8 on September 29th with 180s exposures (ZWO 1600MM, D. O’Donnell). It’s closest approach was September 27th but will still look good for comet observers for a while. See here for details of where to find it.
On the other hand, we have C/2019 2I Borisov which according to it’s now-established orbital parameters doesn’t appear to be from our solar system at all. The last time we saw something like this was with 1I/2017 U1 “Oumuamua” which was the only other object like this we’ve observed coming towards the Sun from outside the solar system. This first event drew much speculations about the objects origins including the idea that it might be an old spaceship considering it’s elongated and rusty appearance!
This time around Borisov which was discovered by amateur astronomer Gennady Borisov on Aug 30th looks to pass within about 2AU of the Earth and observers everywhere are looking forward to capturing and observing this weird interstellar comet. For details of of this approach which lucky for us will be best seen from the Southern Hemisphere in December. Head to Astronomy Now here for more details and we’ll keep you informed at Bintel!
(Comet Borisov – Image credit: Gemini Observatory/NSF/AURA/Travis Rector)