Nearby Type Ia Supernova in NGC 1433 Is Still Brightening
A Type Ia supernova in NGC 1433, 50 million light-years away, is brightening toward a peak expected Nov. 18 to 23 and is visible in small telescopes.
A star has exploded in the spiral galaxy NGC 1433, about 50 million light-years away, and astronomers caught it early. NSF NOIRLab released new images on Nov. 12 of the supernova, named SN 2026ahvu, taken with the Dark Energy Camera and the Gemini South telescope. The explosion is still getting brighter and is expected to peak between Nov. 18 and Nov. 23.
NOIRLab says the supernova is one of the nearest Type Ia explosions seen since SN 2011fe appeared in the Pinwheel Galaxy (Messier 101) in 2011.
How it was found and what it is
The Asteroid Terrestrial-impact Last Alert System (ATLAS) discovered the object on Nov. 2, 2026, when its apparent magnitude was about 17. On the magnitude scale astronomers use, smaller numbers mean brighter objects. Within days, observers reported it at magnitude 13.5.
A spectrum taken on Nov. 3 with the Keck II telescope’s DEIMOS instrument showed it to be a young Type Ia supernova. That is the explosion of a white dwarf, the dense remnant of a star like our Sun, that has pulled matter from a close companion star. NGC 1433 lies in the southern constellation Horologium. The supernova appears to the right of the galaxy’s center and slightly below it. NOIRLab notes that published distance estimates for the galaxy differ, and the release uses roughly 50 million light-years.
What the telescopes are doing
The Dark Energy Camera sits on the Víctor M. Blanco 4-meter Telescope at Cerro Tololo Inter-American Observatory in Chile. It also imaged NGC 1433 before the explosion during the Dark Energy Survey, which ran from 2013 to 2019. Those older images let astronomers compare the supernova’s surroundings before and after the blast, and the sharper Gemini South images add detail on the system.
NOIRLab is coordinating follow-up work with the Blanco telescope and camera, Gemini and the Southern Astrophysical Research (SOAR) Telescope on Cerro Pachón in Chile. Repeated imaging tracks changes in brightness and color, and spectroscopy shows what the expanding material is made of and how fast it moves. The observatory has invited other observatories to add coverage across wavelengths and time zones. The Gemini data are public through the Gemini Observatory Archive.
Why it matters for astronomers
Astronomers use Type Ia supernovae to measure cosmic distances, because their intrinsic brightness is well known. Even so, NOIRLab says questions remain about which stellar systems produce them and exactly how they ignite. Observations in the first days can help separate competing explosion scenarios and look for signs of interaction with a companion star or surrounding material. That evidence can vanish quickly as the debris expands.
The peak brightness will also refine the distance to NGC 1433. NOIRLab cautions that the predicted peak magnitude, 10.5 to 12.1, and its timing are estimates that may change as data arrive. The peak can also occur at different times in different filters.
Can amateurs see it?
NOIRLab says the supernova can already be seen in small to moderately sized amateur telescopes under favorable conditions. It appears as a faint point of light. Visibility depends on location, telescope size, sky darkness and weather, and the object is best placed for southern locations. Its position, right ascension 03h 41m 55.511s and declination −47° 13′ 39.39″, makes it hard or impossible to see from far northern latitudes. Imaging can reveal it in smaller telescopes than visual observing needs.
Source: NOIRLab
