The interstellar comet 3I/ATLAS has been successfully imaged by the NOAA satellite despite its position behind the Sun from October to November 2025. The discovery was made by amateur astronomer Worachate Boonplod, who utilized data from the CCOR-1 coronagraph aboard the GOES-19 satellite to capture this celestial visitor. The comet was detected around its perihelion on October 29, the point at which it comes closest to the Sun.
The imaging was made possible by the coronagraph, which effectively blocks the Sun”s intense light, allowing for the observation of 3I/ATLAS. Traditional ground-based telescopes cannot view the comet during this period due to excessive brightness from solar radiation. Discovered on July 1, 2025, 3I/ATLAS follows a hyperbolic trajectory, which is indicative of its interstellar origin.
As the comet approaches perihelion, it experiences an increase in solar radiation, leading to potential heating and the release of dust and gases. Researchers are closely monitoring its brightness and activity to analyze its composition, as fragmentation may occur, similar to the behavior observed with the comet 2I/Borisov. The CCOR-1 coronagraph primarily focuses on studying the solar corona and related phenomena, including coronal mass ejections, while also recording objects in proximity to the Sun.
Daily images produced by the instrument highlight 3I/ATLAS as a bright point surrounded by a diffuse coma, although no tail has been detected in the processed images by Boonplod. The earlier interstellar object, 1I/”Oumuamua, sparked discussions about the possibility of extraterrestrial technology, although subsequent studies by NASA affirmed its natural composition. The comet 2I/Borisov displayed typical behaviors associated with comets when observed in 2019, both of which follow hyperbolic orbits and signify a single passage through the Solar System.
The findings from 3I/ATLAS are expected to yield valuable insights into materials originating from other stars. Monitoring of the comet is set to continue until March 2026, when it will exit the solar system. Boonplod”s analysis of sequences from GOES-19 in Earth orbit has helped to pinpoint the comet”s location within specific regions of the images. The observed coma shows slight diffusion around its nucleus, with the absence of a tail likely due to the angle of observation.
The data from CCOR-1 allows for real-time tracking of the comet as it nears perihelion. Solar heating is anticipated to reveal the comet”s chemical elements, and comparisons with 2I/Borisov will help scientists understand the variations among interstellar visitors. The comet is expected to emerge from solar glare in November 2025, allowing ground-based telescopes to resume direct observations.
With its hyperbolic trajectory, 3I/ATLAS is on a definitive path out of the solar system by March 2026. Meanwhile, satellites like the ESA“s ExoMars Trace Gas Orbiter have already captured sequences from Mars. Notably, 3I/ATLAS has exhibited a recently confirmed antitail, a phenomenon resulting from interactions with solar wind, indicating the presence of volatiles through gas release. Future spectral analysis aims to identify unique components of this interstellar object.
The GOES-19 satellite operates in a geostationary position, with the CCOR-1 providing valuable daily images for monitoring space weather. The detection of 3I/ATLAS validates the instrument”s capabilities in observing sungrazer comets, and the data collected will be accessible through specialized platforms. Continuous monitoring will focus on the integrity of the comet”s nucleus, as any fragmentation would offer indirect samples of interstellar material.
