The Nasa TESS satellite compiled a sequence of images that results in a 28-hour video showing the interstellar comet 3I/ATLAS moving through space. The observations took place between January 15 and 22, 2026, a period in which the object was moving away from Sol after its perihelion. In the record, the comet appears as a bright point with an anti-solar tail directed towards Sol, amid background stars.
The compilation was carried out by Daniel Muthukrishna, an MIT researcher who is part of the TESS team. A brief interruption in observations occurred between January 15th and 18th due to a problem with the satellite’s solar panels, which went into safety mode. The remaining images allowed us to clearly reconstruct the object’s trajectory.
TESS, designed primarily to detect exoplanets through transits, has a wide field of view that facilitated 3I/ATLAS capture. Satellite public Dados is available on Arquivo Mikulski to Telescópios Espaciais.
- Comet 3I/ATLAS was discovered on July 1, 2025 by the ATLAS system at Chile.
- Its hyperbolic trajectory confirmed an interstellar origin within days of detection.
- The object passed perihelion on October 30, 2025, about 1.4 astronomical units from Sol.
Operation of the TESS satellite
Transiting Exoplanet Survey Satellite observes large sections of the sky for periods of approximately one month. Sua main function is to identify variations in the brightness of distant stars caused by the passage of planets. The wide field of view allowed 3I/ATLAS to be recorded in May 2025, almost two months before the official discovery.
After stacking thousands of images from that period, astronomers retroactively identified the object. Naquela phase, the comet showed constant brightness, without evident signs of a tail or prolonged activity. The January 2026 observations revealed different behavior, with the antisolar tail visible due to the position relative to Sol.
Features observed in the video
The compiled video shows 3I/ATLAS as a fast-moving dot against the stellar background. The anti-solar tail points in the direction of Sol, a common phenomenon in active comets that release dust and gas. TESS’ low angular resolution prevents fine details, but the full sequence allows for possible brightness variations to be analyzed.
Researchers plan to examine the data for periodicity related to the comet’s rotation period, estimated to be about 7.1 hours based on previous images of Telescópio Espacial Hubble. Collaboration between experts includes analysis of oscillations in the tail that may indicate rotation of the nucleus.
The cometary activity of 3I/ATLAS intensified after perihelion. Observações spectroscopic images indicate the presence of relatively large dust grains, with a reddish color similar to type D asteroids.
Comparison with previous interstellar objects
3I/ATLAS is the third interstellar object confirmed to pass through Sistema Solar. The first, 1I/’Oumuamua, detected in 2017, had an elongated shape and no visible coma. The second, 2I/Borisov, identified in 2019, exhibited a clear tail and behavior more typical of Sistema Solar comets.
Unlike ‘Oumuamua, 3I/ATLAS developed a clear coma and tail from greater distances. Sua composition appears to include irradiated organic compounds, responsible for the reddish hue observed. The excessive hyperbolic trajectory confirms that the object is not gravitationally bound to Sol.
Additional observations by Hubble
Telescópio Espacial Hubble captured 36 images of 3I/ATLAS between November 2025 and January 2026. Essas observations occurred during a rare alignment between the comet, Terra and Sol, with an accuracy of 0.69 degrees. Hubble images offer higher resolution compared to TESS video.
In them, details of the tail and possible jets of material become more evident. The Hubble data serves as a reference for calibrating TESS sequence analyses. Ambas the combined sources allow for a more complete study of rotation and surface activity.
Context of discovery and trajectory
The initial detection of 3I/ATLAS occurred when the object was about 4.5 astronomical units from Sol. Telescópios terrestrials quickly confirmed the presence of diffuse coma and tail-like elongation. Observações subsequent tests using multiple instruments validated the cometary nature.
The comet passed close to the orbit of Marte and continued moving away from Sol after January 2026. Sua high speed prevents gravitational capture by Sistema Solar. The passage represents a unique opportunity to study primordial material from another star system.
Next Observation Steps
On March 16, 2026, 3I/ATLAS will pass close to the Hill radius of Júpiter. The Juno probe, in Jovian orbit, will be able to observe the comet from a distance of approximately 53.6 million kilometers. Juno’s instruments include optical and infrared cameras, as well as particle and magnetic field sensors.
This proximity will allow collection of complementary data to the optical records of TESS and Hubble. The probe’s microwave radiometers and radio antennas can detect specific emissions. The combination of all observations contributes to a broader understanding of the composition and behavior of interstellar objects.
Scientific importance of observations
Studies of objects like 3I/ATLAS help understand the formation of distant planetary systems. The presence of organic compounds and dust suggests similarities to comets from the outer Sistema Solar. Diferenças in the proportion of elements may indicate variations in interstellar chemistry.
Analysis of surface rotation and activity reveals volatile ice sublimation processes. Dados collected by multiple Nasa missions form the basis for theoretical models about the distribution of interstellar objects in Via Láctea. The rarity of these visitors makes each observation valuable to astrophysics.
TESS records demonstrate the satellite’s versatility beyond hunting for exoplanets. The ability to detect fast-moving objects expands mission applications. Futuras observations of interstellar comets or asteroids can benefit from similar image stacking techniques.
Public data and international collaboration
All TESS images are publicly available for download and analysis. Independent Pesquisadores can contribute to additional studies on brightness variability or tail morphology. Collaboration between institutions includes experts from different countries.
The involvement of amateur and professional astronomers in continuous monitoring complements satellite data. Redes of ground-based telescopes continue to track 3I/ATLAS while it remains visible. Integration of all sources guarantees complete coverage of the comet’s passage.
- Nasa missions that observed 3I/ATLAS:
- Hubble: high-resolution images during alignment.
- Webb: infrared spectroscopy.
- TESS: broad temporal sequence.
- Juno: Observation planned in March 2026.
- Others: Swift, SPHEREx and probes at Marte.
The passage of 3I/ATLAS represents a milestone in modern observational astronomy. The collected data remains available for future research. Avanços in understanding interstellar objects depends on the ongoing analysis of these unique observations.