Home=Current Comets: C/2026 A1
| The German Group
| Tutorials
| Archive
| Projects, publications
| Images
| Contact
A member of the Kreutz group was discovered as the first comet of 2026 on Jan. 13 in the constellation Columba as part of the MAPS project. A total magnitude of 18.0 was determined via the images of comet C/2026 A1 (MAPS), with a diffuse coma of 12" diameter. Remote images taken by Michael Jäger and Gerald Rhemann on Jan. 18 showed a 2.5' coma of total brightness 16.1 mag. Subsequently, the comet could be tracked back to Dec. 18, 2025. This is the Kreutz comet that has been observed at the greatest solar distance to date. The comet will pass perihelion on Apr. 4, 2026 at a solar distance of only 0.0057 AU (CBET 5658). Assuming an average brightness development it could become as bright as –2 mag during a very short time, but it will then be positioned very close to the Sun. Thus it is more likely that only solar probes will be able to track its development during the days around perihelion.
However, its absolute magnitude is well below the Bortle limit. This means that there is a high probability that the comet will disintegrate while approaching the Sun. On the other hand, it is possible that it will not show an average brightness development, that its absolute brightness will increase significantly, and that it will then be able to reach or just survive perihelion. Examples are comets C/2006 P1 (McNaught) and C/2011 W3 (Lovejoy). Assuming an average brightness development the comet would be brighter than 16 mag until the end of May. During this period it will initially move retrograde from the constellation Eridanus to the constellation Pisces. Thereafter moving prograde from Pisces to Orion. It will remain virtually invisible from Central European locations. Only in the few days around perihelion could it possibly be spotted with binoculars or a telescope in the bright twilight, provided it actually becomes brighter than 0 mag for a short time. Possibly, forward scattering could be helpful, which could cause a brightness increase of more than 1 agm from 14hUT to 23hUT on Apr. 4, peaking at about 4.5 mag at 16hUT. If it survives its extreme proximity to the Sun attempts can be made to locate the comet in the bright evening twilight in the days around perihelion. Earth will cross the comet's orbital plane on March 29.
By mid-February only 31 CCD observations from 11 observers could be used for a rough analysis. These show an extremely rapid increase in activity, which can be represented by the parameters m0=10.0 mag / n=10, resulting in an unrealistic peak brightness of –20 mag. It must therefore be assumed that this increase in activity will level off significantly in the near future. More likely are parameters m m0=12.0 mag / n=4 (or even lower), which would still result in a (very short-term) maximum brightness of about –9 mag (but this would probably still be significantly too bright) – always assuming that the comet survives its perihelion passage unscathed. The additional brightening due to forward scattering on Apr. 4 is: 14hUT: –1.0 mag, 15hUT: –4.0 mag, 16hUT: –4.5 mag, 17hUT: –2.5 mag, 18hUT: –2.0 mag, 19hUT: –1.5 mag.
Andreas Kammerer