Oumuamua, the first interstellar object discovered in the Solar System, has been a focus of discussion and interest since its first sighting in October 2017 . Now, the latest results obtained suggest that Oumuamua has slightly increased its speed according to observations and data obtained by NASA and the European Space Agency through the Hubble Space Telescope. The operation has been carried out with the support of an international team of astronomers and numerous ground-based telescopes such as the Canada-France Hawaii Telescope , the ESO’s Very Large Telescope and the Gemini South Telescope .
The team led by Marco Micheli , from the European Space Agency, affirms that the visiting object continues to lose speed due to the gravitational attraction that the Sun exerts on it, but even with this it shows a speed higher than expected. Of the different scenarios that have been analyzed to explain this behavior, it seems that the most likely option is that the body is degassing , losing material from its surface due to the impact of the Sun and causing a constant acceleration that would be generating said impulse. On June 1, Oumuamua was traversing the Solar System at a speed of approximately 114,000 kilometers per hour.
If this theory is confirmed, the original idea would be questioned by considering the interstellar object Oumuamua a comet and not an asteroid, as was initially believed. The characteristic that most differentiates a comet from an asteroid is that the former has on its surface a layer of ice and volatile materials that vanish with the heat generated by the Sun and create a characteristic ‘tail’ in these bodies, also causing a acceleration and changes in body velocity. Asteroids are celestial bodies made up of metallic and rocky materials that come from places partially close to the Sun and that, therefore, do not have that layer of volatile materials that make up the comet’s tail.
Astronomical confusion
“We think it is a rare little comet ,” declared Marco Micheli after the latest results. Another factor that reinforces this new theory is that the momentum that accelerates it seems to decrease as it moves away from the Sun, a characteristic behavior of comets that receive less heat from the star and lose less material from its surface that pushes it.
According to official statements, the error stems from the fact that no degassing samples were observed, the accumulation of dust and gas called ‘coma’ or the characteristic tail of the comet. The head of the team that discovered the Oumuamua in 2017, Karen Meich , believes that these elements were not detected because ‘the Oumuamua has too large and coarse dust particles’ as the smallest ones have been destroyed during its trip. This would cause the wake left by the comet, made up of the larger particles, not to be bright enough for the Hubble Telescope to detect, confusing the scientific team.
But not only the nature of this celestial body seems uncertain. The latest observations were made in order to determine the trajectory of Oumuamua and to be able to trace the route to its solar system of origin, a task that has been complicated due to the acceleration detected. Olivier Hainaut, a member of the European team, concludes that “the true nature of this enigmatic interstellar nomad will remain a mystery .”
Reference: Marco Micheli & team. ‘Non-gravitational acceleration in the trajectory of 1I72017 U1 (‘ Oumuamua) ‘, Nature Journal (2018). Doi: https://doi.org/10.1038/s41586-018-0254-4
