” These envelopes are of excellent value for our understanding of the advancement of stars in their final stage. They assist us to understand how they enrich the interstellar space with heavy elements, which are then in turn important for the advancement of planetary systems, such as our own,” explains Kimeswenger the value of the recently found galactic nebulae and includes an explanation for why the probability of their discovery is low: “They are too large for the field of view of modern telescopes and at the very same time they are very faint.
The starting point for this special discovery is a group of German-French amateur astronomers: With painstaking work they browsed historical celestial images for unidentified things in the now digitized archives and finally discovered a fragment of a nebula on photographic plates from the 1980s.
International cooperation fixes puzzle
With their finding, the group gotten in touch with worldwide scientific professionals, including the Department for Astro and Particle Physics at the University of Innsbruck, which is really experienced in this field. By assembling and integrating observations from the previous 20 years, originating from public archives of numerous telescopes and with information from 4 different space satellites, the scientists in Innsbruck were able to dismiss their first assumption, namely the discovery of a planetary nebula caused by the residues of passing away stars. The massive extent of the nebula finally ended up being evident with the aid of measurements taken by telescopes in Chile. Researchers in the USA finally completed these observations with spectrographs: “The size of the main cloud is 15.6 light-years across, almost 1 million times larger than the range of the earth to the sun and much larger than the distance of our sun to its nearest neighboring star. Pieces as large as 39 light-years apart have actually also been discovered. Since the item lies somewhat above the Milky Way, the nebula had the ability to develop mainly undisturbed by other clouds in the surrounding gas,” Kimeswenger explains the discovery.
Model of the brand-new class of galactic nebulae
By integrating all this details, the scientists have actually been successful in creating a design of the things: It includes a close double star of a 66,500-degree white dwarf star and a typical star with a mass slightly below that of the Sun. Both orbit each other in only 8 hours and 2 minutes and at a distance of only 2.2 solar radii. Due to the little range, the buddy star with a temperature level of just about 4,700 degrees is strongly heated at the side dealing with the white dwarf, which results in severe phenomena in the spectrum of the star and to extremely regular variations in brightness. Around both stars there is a massive envelope consisting of the outer product of the white dwarf. At just over one solar mass, this material is much heavier than the white dwarf and its companion star and was ejected into area some 500,000 years back.
Another part of the puzzle related to the discovery of the new class of galactic nebulae has actually not yet been fixed, Stefan Kimeswenger says: “It is even possible that this system is associated with a nova observation made by Korean and Chinese astronomers in 1086. In any case, the positions of the historical observations match effectively with those of our object described here.”
Discovery image of the nebula. For this image, 120 private direct exposures had actually to be combined to acquire a total direct exposure time of 20 hours. The images were taken control of a number of months from Brazil. Credit: Maicon Germiniani
A worldwide team of astronomers led by Stefan Kimeswenger from the Department of Astro and Particle Physics, together with scientific amateurs, has actually recognized a brand-new class of stellar nebulae. This supplies an important structure block in the understanding of stellar development and reveals the significance of international cooperation between university research study and community science.
Because a really big portion of stars are in binary stars, this affects the advancement at the end of their lives. In close binary systems, the inflating external part of a star combines as a common envelope around both stars. Inside this gas envelope the cores of the two stars are practically undisturbed and follow their advancement like independent single stars,” discusses astrophysicist Stefan Kimeswenger.
Discovery thanks to amateur astronomers
Lots of outstanding systems being known to be remnants of such a development. Stellar systems which are simply about to establish a typical envelope had actually already been found due to their particular and high brightness.
Given that a really big portion of stars are in binary stars, this impacts the evolution at the end of their lives. In close binary systems, the inflating outer part of a star combines as a common envelope around both stars. Inside this gas envelope the cores of the 2 stars are practically undisturbed and follow their advancement like independent single stars,” discusses astrophysicist Stefan Kimeswenger. By combining all this info, the scientists have been successful in developing a design of the item: It consists of a close binary system of a 66,500-degree white dwarf star and a typical star with a mass somewhat below that of the Sun. Due to the small distance, the companion star with a temperature level of just about 4,700 degrees is strongly heated at the side dealing with the white dwarf, which leads to severe phenomena in the spectrum of the star and to very regular variations in brightness.
