Science & Technology

Astronomers Discover a New Class of Galactic Nebulae

Discovery image of the nebula. In this image, 120 individual exposures had to be combined to get a total exposure time of 20 hours. The image was taken from Brazil over several months. Credit: Maicon Germiniani

An international team of astronomers, led by Stefan Kimeswenger of the Department of Astronomy and Particle Physics, has identified a new class of galaxy nebulae with scientific amateurs. It provides an important component in understanding stellar evolution and demonstrates the importance of international cooperation between university research and regional science.

For the first time, scientists have succeeded in providing evidence of a fully developed shell of the Common Envelope System (CE), which is the phase of the common envelope of a star system, starting with discoveries by scientific amateurs. “Towards the end of their lives, normal stars bulge into red giants. This affects the evolution of their end of life, as most of the stars are in binaries. In close-range star systems. However, inside this gas envelope, the cores of the two stars are virtually undisturbed and independent, with the expanding outer part of the star merging as a common envelope around both stars. It’s evolving like a single star, “explains astrophysicist Stefan Kimeswenger. Researchers are currently publishing the results in the journal Astronomy & Astrophysics.

Discovered thanks to amateur astronomy

Many star systems are known to be remnants of such evolution. Their chemical and physical properties act as fingerprints. Also, the star system that is trying to develop a common envelope has already been discovered because of its particular high brightness. However, the fully developed envelope of CE and its release into the interstellar space have not previously been observed in this form.

“These envelopes are very important in understanding the evolution of stars in the final stages. In addition, they help us understand how to enrich the interstellar space with heavy elements. Elements are important for the evolution of planetary systems like ourselves, “Kimeswenger explains and adds an explanation for the importance of newly discovered galaxy nebulae. It is as follows. “They are too big for the field of view of modern telescopes and at the same time very dark. Moreover, their lifespan is quite short, at least on the time scale of the universe. It’s only hundreds of thousands of years.”

The starting point for this unique discovery is a group of amateur astronomyists from Germany and France. They worked hard to search historical astronomical images of unknown objects in their now digitized archives, and finally found a fragment of the nebula on a 1980s photographic plate.

International cooperation solves puzzles

With their discovery, the group contacted international scientific experts, including the Department of Astroparticle Physics at the University of Insbruck, who is very experienced in this field. Innsbruck researchers summarize observations from various telescope public archives over the last two decades and combine them with data from four different space satellites to rule out the first assumption: the discovery of a planetary nebula. I was able to. The wreckage of a dying star. With the help of measurements made with the Chilean telescope, a huge area of ​​the nebula has finally been revealed. American scientists have finally completed these observations with a spectroscope. “The diameter of the main cloud is 15.6 light-years in diameter, almost one million times the distance from Earth to the Sun, much larger than the distance from Sun to Sun. The closest neighboring star. In addition, 39 light-years away. Fragments of the sun have also been found, as the object is a little above. Milky Way, The nebula was able to develop almost undisturbed by other clouds of surrounding gas, “explains Kimeswenger.

A new class of galaxy nebula models

By combining all this information, researchers have succeeded in creating a model of the object. It consists of a close binary system of 66,500 degrees. White dwarf A normal star with a mass slightly smaller than the mass of the star and the sun. Both orbit each other at a distance of only 2.2 solar radii in just 8 hours and 2 minutes. Due to the short distance, the companion star, which has a temperature of only about 4,700 degrees Celsius, is heated strongly on the side facing the white dwarf. This causes extreme phenomena in the star’s spectrum, resulting in very regular changes in brightness. Around both stars is a huge envelope of material outside the white dwarf. This material, with a solar mass of just over 1, is heavier than the white dwarf and its companions and was released into space about 500,000 years ago.

Another part of the puzzle related to the discovery of a new class of galaxy nebulae has not yet been solved, says Stephen Kimeswenger. In any case, the position of the historical observation is very well in line with the position of the object described here. “

Astronomers Discover a New Class of Galactic Nebulae Astronomers Discover a New Class of Galactic Nebulae

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