comet 3I/ATLAS: A Unique Visitor from Beyond Our โSolar System
comet 3I/ATLAS is โcurrently attracting significant attention from astronomers worldwide due to its unusual characteristics, โคdistinguishing โit from typical comets observed within our solar system.This marks only the third โtime โคscientists have identifiedโฃ an objectโค originating from โฃoutside our planetary neighborhood, following the discoveries of ‘oumuamua and comet 2I/Borisov. Notably, 3I/ATLAS is considerably brighter than either of its predecessors.
The comet’s distinctiveness stems from its highly eccentric orbit. While most comets,notably short-period ones,have an eccentricity around 1โ (and often below),3I/ATLAS boasts anโค eccentricity exceeding 6,confirming itsโ interstellar originโ according to Martin Biely of the Society for Interplanetary Matter. Eccentricity measuresโ the degree of an orbit’s elongation and theโฃ position of its focal points.
Further analysis reveals compositional differences. Martin Maลกek from the Czech Astronomical Society notes a higher ratio of carbon dioxide to water in theโ comet’s coma, and also an increasedโข nickel content in its spectrum. These variations suggest the comet formed within a different planetary system, under distinct conditions during the protoplanetary disk stage. This makes 3I/ATLAS a valuable subject for astronomical research.
Recently, observations of a tail โappearing to pointโ away from the Sun sparked speculation about the comet’s artificial nature. However, Maลกek clarifies this is a natural phenomenon known as โan “anti-tail.” This occurs due to larger โฃdust particles (around 0.1 millimeters in size) behaving differently than smaller particles when exposed to solar radiation. Smaller particles are more strongly influenced by the sun’s radiation, whileโ larger particles follow a different trajectory, creating the appearance of a tail directed away from the sun.
Currently, the comet is not visible โขin the evening โsky, having last been observed at the end of September. However, it was recently detected by โprobes near Mars. 3I/ATLAS will reach its closest approach to the Sunโ (perihelion) on October 29th and will become visible again inโฃ the morningโค sky in earlyโ november. Astronomers estimate its โbrightness will be between magnitudesโข 10 and 11, perhaps making it observableโ with telescopes ofโข atโ least 20 centimeters โคin diameter.
The comet will traverse the constellations Virgo in November and Leo in โDecember, with improving observation conditions, โthough its brightness is expected to diminish overโ time. Despite this, Biely encourages observation, emphasizing that 3I/ATLAS is the brightest of the threeโ interstellar objects discovered to date.
The size of the comet’s coreโ remains uncertain, with โคcurrent estimates ranging from 0.5 โto 5 kilometers, as it has not yet been examined by a โขclose-range probe.
