Comet P/2016 J3 (STEREO) was recently observed by several including: I41 Palomar Zwicky Transient Facility; G96 Mt. Lemon Survey; K. Sarneczky at K88, GINOP-KHK, Piszkésteto in Hungary, M. Jaeger at Stixendorf, Austria; H. Sato is H06 at Mayhill, NM; K. Yoshimoto, Hirao, Kumage, Yamaguchi, Japan; and K. Kadota, Ageo, Japan.
This comet has brightened to near 14th magnitude and is at a low 37 degree solar elongation and high phase angle due to its position interior to Earth’s orbital distance.
Michael Jager, Stixendorf, Austria, reported P/2016 J3 (STEREO) P/2016 J3 (STEREO) at magnitude 14.0 on 2021-Jan-07 to S. Yoshida’s web pages.
Gideon van Buitenen, Dordrecht, NL, reported P/2016 J3 (STEREO) at magnitude 14.7 on 2021-Jan-08.72 on COBS.
Revised orbital elements for 2021 and astrometry are pending release of a MPEC. The comet returns to perihelion on January 25, 2021 at 0.526 au, 22 degrees solar elongation, 135 degrees phase, and as bright as 12th magnitude. Forward scattering is expected to enhance its brightness. Due to low elongation it is already a difficult target.
In the second week of February 2021, P/2016 J3 will be observable by observers in the southern hemisphere but rapidly fading.
Comet P/2016 J3 (STEREO) was found by Scott Ferguson in STEREO HI-1 images in May 2016 as bright as magnitude 8 to 9. The initial orbit and astrometry were published in MPEC 2016-K41 : COMET P/2016 J3 (STEREO) (2016 May 31).
Comet P/2016 J3 (STEREO) had never been imaged or observed from the ground until it was recently recovered by I41 Palomar Zwicky Transient Facility and others.