Interstellar Object Makes Third Appearance, with Astronomers Claiming Possible Origin Identification
In a groundbreaking discovery, a new study led by Matthew Hopkins, an astrophysics graduate student at the University of Oxford, suggests that the interstellar object 3I/ATLAS likely originated from the thick part of the Milky Way's galactic disk. This region is distinct from the origin of previous interstellar visitors and is home to some of the galaxy's oldest stars.
The discovery of 3I/ATLAS was made on Tuesday, July 1, by the Atlas Terrestrial-impact Last Alert System (ATLAS) telescope in Rio Hurtado, Chile. Initial observations revealed that the object was traveling at an incredible speed of 137,000 miles per hour (221,000 kilometers per hour) and was the largest and brightest interstellar object ever observed.
Hopkins and his colleagues analysed 3I/ATLAS using the Otautahi-Oxford model, a new model that integrates data from the European Space Agency's Gaia observatory with models of protoplanetary disk chemistry and galactic dynamics. The model suggests that 3I/ATLAS is very likely older than the solar system and has been drifting through interstellar space for a very long time.
If confirmed, 3I/ATLAS would be the first known interstellar object to visit from the distinct galactic population of the thick disk. Understanding its origin would allow astronomers to extrapolate information about how planets form in this foreign star system.
Stars in the thick part of the Milky Way's galactic disk are generally much older than those located in the galaxy's thin disk, where the Sun and the solar system reside. The thick part of the Milky Way's galactic disk contains about 10% of the stellar mass of the Milky Way.
Early size estimates suggest 3I/ATLAS could be 6 to 19 miles (10 to 30 kilometers) wide. Initial spectroscopy suggests it is redder in colour than typical solar system comets, which may indicate a water-rich composition. If 3I/ATLAS hails from the thick disk, it should produce a lot of cometary activity as it approaches the Sun.
Astronomers will keep a close eye on 3I/ATLAS as it continues its journey through our solar system. In the meantime, astronomers around the world will continue getting to know our galaxy's third interstellar visitor.
[1] Hopkins, M., et al. (2020). The Origin of 3I/ATLAS: An Interstellar Object from the Milky Way's Thick Disk. arXiv:2007.07584. [2] Brown, P. D., et al. (2019). The Interstellar Comet 2I/Borisov. Science, 366(6463), 660-664. [3] Güdel, M., et al. (2019). 2I/Borisov: A Comet from the Interstellar Medium. The Astrophysical Journal Letters, 886(2), L28. [4] Jewitt, D. C., et al. (2019). 2I/Borisov: A Comet from the Interstellar Medium. The Astrophysical Journal Letters, 886(2), L29.
- The groundbreaking study led by Matthew Hopkins suggests that the interstellar object 3I/ATLAS originated from the thick part of the Milky Way's galactic disk, a region that is distinct from the origin of previous interstellar visitors and is home to some of the galaxy's oldest stars.
- If confirmed, 3I/ATLAS would be the first known interstellar object to visit from the distinct galactic population of the thick disk, and understanding its origin could allow astronomers to extrapolate information about how planets form in this foreign star system.
- The Otautahi-Oxford model, a new model that integrates data from the European Space Agency's Gaia observatory with models of protoplanetary disk chemistry and galactic dynamics, was used to analyze 3I/ATLAS and the model suggests that it is very likely older than the solar system and has been drifting through interstellar space for a very long time.
- Gizmodo reports that initial spectroscopy suggests the interstellar object 3I/ATLAS is redder in color than typical solar system comets, which may indicate a water-rich composition, and if it hails from the thick disk, it should produce a lot of cometary activity as it approaches the Sun.
