Investigated using complex radio telescope ALMA, located in Chile’s Atacama desert, a quadruple star system really surprised astronomers. It turned out that she has one feature that is never met in practice and up to this point existed only in the minds of theorists. However, the results of the conducted observations, published in the journal Nature Astronomy, once again prove that the cosmos is full of mysteries that are just waiting to be discovered.
Quadruple star system that contains two pairs of binary stars in fact are not unusual. Yes, they are quite rare, but do occur. Also the presence of the protoplanetary disk (rings of gas and dust which form the future of the planet) is not a revelation. The studied system HD 98800 is approximately 146 light years from Earth in the constellation of the Cup and has all these features. What surprised the scientists? Incredibly unique protoplanetary disk that comes with it.
System HD 98800 consists of four bodies, divided into pairs of inner and outer. The inner pair of stars, called BaBb, are in close proximity to each other at a distance of about 1 astronomical unit (1 a.e. = distance from the Earth to the Sun). External lights pair, AaAb, located much further from each other – 54 astronomical units, which is significantly farther than the distance between Pluto and the Sun (about 40.e.). The outer pair of lights no is not interesting. The most interesting thing in the system – the inner pair of stars and a surrounding protoplanetary disk.
Usually the protoplanetary disk is in the same plane as the orbital plane of the other objects in the system. As it turned out, this rule does not work with the system HD 98800. The latter has a disk that is oriented exactly perpendicular to the plane of rotation of the component stars. In other words, instead of the conventional horizontal plane to the West-East drive is located in the plane North-South. To do this, open system like HD 98800 existed only in theory.
“The rich gas and dust, protoplanetary disks are observed around almost all the young stars. We know that at least within 1/3 of the disks have single stars, see planets. Some of these planets under the action of certain forces can be displaced relative to the axis of rotation or the equator of the star. We always wondered about whether such a strange dynamics in systems with double stars. Computer modeling shows that in such systems, the development can go in two ways: either the planet will rotate in the same plane with the stars, or perpendicular to them. But we did not have this evidence,” says the study’s lead author from the University of Warwick (UK) Grant Kennedy.
Astronomers knew about the existence of the system HD 98800 for several years. In previous studies there has been an attempt of observation of the movement of the inner pair of lights. However, thanks to the powerful array “Atkarskoy a large antenna array of millimeter range” the Kennedy team managed to get through the dense layers of gas and dust the disk just now. The use of ALMA allowed us to get the clear picture of what it looks like system HD 98800, and uncover the amazing orientation in it the protoplanetary disk.
Prospective view from the surface of a hypothetical extrasolar planets inside of the protoplanetary disk in the system HD 98800 BaBb
According to the authors of the study, assuming that the inside of the protoplanetary disk is formed exoplanet, the sky from the surface would look just incredible. Being on such a planet, a ring of dust and gas of the protoplanetary disk would look like a bright streak rising from the horizon, passing right over your head, and then hiding on the opposite side. At the same time, two stars of the system periodically hide behind the disk again and then came out from behind him, sometimes throwing to the surface a particular shade.
“This is a surprising result of the observations,” says astronomer at Caltech’s Konstantin Batygin, who do not participate in this study.
“This configuration is what can be expected from the combinatorial effects of gravity and the internal dissipation inside the protoplanetary disks. The opening of the first such systems suggests that the previous simulation actually proved to be very accurate. Now there is no doubt that in the future we will be able to find the same system.”
An astronomer at Princeton University, Daniel Tamayo, also participated in the study, sharing the joy of the research group Kennedy, describing published in Nature Astronomy work as “incredible article on the unique and beautiful discovery.”
“It’s funny that such a bizarre mathematically model the dynamics of the Arctic planetary disk around a binary system is a relatively stable configuration. Initially it was unclear if she can even appear in nature. In earlier studies mentioned about the opening of the slightly inclined protoplanetary disks, but this option was found for the very first time”.
The next challenge for astronomers will be finding a similar system, but at different stages of their evolution.