Haleakal\u0101-based Pan-STARRS1 detected object A/2017 U1 on 19 October 2017. Rapid follow-up revealed a hyperbolic orbit unlike any Solar System body. The International Astronomical Union soon redesignated the object 1I/'Oumuamua, meaning "scout" in Hawaiian. Telescopes worldwide scrambled to record photometry and spectra showing a reddish, elongated body with no visible coma.
Breakthrough Listen used the Green Bank Telescope in December 2017 to search for radio emissions. None were found. A 2018 Nature paper reported a non-gravitational acceleration, suggesting volatile outgassing. Subsequent Spitzer observations failed to detect an infrared signature, implying a small size or high reflectivity. The object's true nature remains uncertain, fueling speculation about its origin.
Timeline
Observational data
- Pan-STARRS and VLT images show an elongated reddish body roughly a hundred metres long.
- Spectroscopic studies detect no coma, implying a dry surface or depleted volatiles.
- Breakthrough Listen and other radio campaigns report silence across multiple bands.
- Spitzer and other infrared telescopes provide only upper limits on diameter.
References
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IAU – The IAU approves new type of designation for interstellar objects ↩
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Minor Planet Center – MPEC 2017-U181 and MPEC 2017-U183 ↩
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Minor Planet Center – MPEC 2017-V17 ↩
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Breakthrough Listen – Initial results from observations of 'Oumuamua ↩
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Micheli et al. 2018, Nature – Non-gravitational acceleration in 1I/'Oumuamua ↩
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JPL – NASA learns more about interstellar visitor 'Oumuamua ↩