Interstellar object Omwamwi may not be a comet but not asteroid

Astronomers again doubted cometary nature first discovered interstellar object might Omului — a cross between a comet and an asteroid.

Межзвездный объект Оумуамуа может оказаться не кометой, но и не астероидом

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A year has passed since then, as the astronomers noticed a small body crossing the Solar system on that trajectory and with such speed that, in the end it was identified as an interstellar object. The name he received the appropriate — 1I/Omwamwi: 1 — first, I — interstellar (Interstellar), Omului — “guest” or “messenger” in Hawaiian (the object was first noticed by researchers working in the Observatory in Hawaii). It is hardly surprising that Omwamwi attracts the attention of scientists, which, however, still can’t figure out its nature.

Initially, it was considered a comet, then an asteroid. A few months ago, astronomers found that Omwamwi could receive additional acceleration due to solar evaporation of the light substances from the surface, and again decided that it was a comet. On the same version and indicates the study of the spectrum Omwamwi: it found a mass of water ice, characteristic of comets. But in the new work of the Cambridge astrophysics Roman Rafikov (Roman Rafikov) this version is again questioned. The corresponding article submitted to the online library of preprints

In fact, no matter how many arguments in favor of the hypothesis of “cometary nature” Omwamwi nor cited, one thing is perfectly clear: she had no tail, which should be disposed of comets approaching the Sun. Of course, the tail could be too sparse, and the observation of the rapid object — too short, so the tail we can simply ignore. However, the Professor Rafikov indicates that the evaporation of the substance from the surface Omwamwi, which could create a tail and to give it extra speed in any case should affect the nature of the rotation of the object.

Moreover, according to the scientist’s calculations, if additional acceleration is indeed due to this process, it would have to spin up Omwamwi to such a high speed that any comet would have collapsed under the action of centrifugal forces. “There are strong arguments in favor of both versions, — added Roman Rafikov. — But if an asteroid with a very unusual, exotic scenario of education.”

It may be a strange interstellar the guest indicates a significant disadvantage of the existing classification of small celestial bodies. We used to divide them into rocky residents of the inner regions of the Solar system, asteroids are moving along relatively circular paths, and icy comets that are more numerous in the far outer areas and arriving to the Sun on highly elongated orbits. Exotic features Omwamwi can say that this binary division is not precise enough and there are not only “strict” asteroids and comets, but also intermediate variants.