(ORDO NEWS) — Astronomers were able to determine the nature of the unusual Blue Ring nebula, discovered 16 years ago. It turned out that it is a substance ejected from a binary star system at the stage of merging of its components. The article was published in the journal Nature.
A large number of stars in the Universe are not single objects, but are included in multiple systems, with binary stars being the most common. About half of the stars in the Milky Way are part of binary systems and at some stage of evolution can merge, which leads to the formation of unusual objects such as magnetic and blue straggling stars, as well as fast rotators. Despite the fact that several merger events have been observed directly, most of the processes occurring in this process remain poorly understood due to the opaque shell of gas and dust surrounding the system after the merger.
A group of astronomers led by Keri Hoadley of California Institute of Technology has published the results of an analysis of observations of the Blue Ring nebula associated with the star TYC 2597-735-1. This object was originally discovered by the GALEX Space Ultraviolet Telescope in 2004. Scientists have studied the nebula using a number of ground-based and space-based telescopes, including the Hale and Keck telescopes, as well as WISE and Spitzer.
The nebula has an estimated mass of four that of Jupiter, it is located about 6.2 thousand light years from the Sun and 4.9 thousand light years above the plane of the Milky Way. Its physical size is approximately 13 light years and is estimated to be less than five thousand years old. In the center of the nebula is the star TYC 2597-735-1 with a mass from 1 to 2.1 solar masses and a radius of about 11 solar radii, its luminosity is 110 times that of the Sun. The star emits unusually intense infrared and ultraviolet radiation. The nebula itself has a bipolar structure, and the visible rings are shock waves.
Based on the simulations carried out, astronomers came to the conclusion that in the past, TYC 2597-735-1 merged with its low-mass (0.1 solar mass) companion, while part of the matter formed an accretion disk of gas and dust, extending several astronomical units from stars, and some of the matter was ejected from the system, giving rise to a nebula. This discovery provides scientists with a unique opportunity to study the morphology of the binary system after the merger, and future telescopes may find a number of similar objects in the Milky Way.
Earlier, we talked about how astronomers discovered a binary star system in the center of the planetary nebula Abell 30 and what an unusual gas structure looks like around the binary star system HD101584.
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