The mean size of the observed Mira stars and their surrounding molecular layer is compared to the size of the inner Solar System. The Earth’s, Mars’ and Jupiter’s orbits are shown, as well as the Sun’s position. The picture illustrates that when the Sun becomes a Mira-type star in about 5 billion years, it will nearly reach Mars’ orbit and its surrounding molecular layer will extend far beyond Mars.
For the first time, an international team of astronomers led by Guy Perrin from the Paris Observatory/LESIA, (Meudon, France) and Stephen Ridgway from the National Optical Astronomy Observatory (Tucson, Arizona, USA) has observed the close environment of five so-called red giant Mira stars, using astronomical interferometric techniques. They found that the observed Mira stars are embedded in a shell of water vapor and possibly of carbon monoxide that extends to twice the stellar radius. Studying these Mira stars is of particular interest since they are now undergoing a late stage of the evolution that one-solar mass stars, including our Sun, experience. Therefore, these stars illustrate the fate of our Sun five billion years from now. Would such a star, including its surrounding shell, be located at the Sun’s position in our solar system, it would extend far beyond Mars.
Although they are really very large (up to a few hundred solar radii), red giant stars are point-like to the unaided human eye on Earth, and even the largest telescopes fail to distinguish their surfaces. This challenge can be overcome by combining signals from separate telescopes using a technique called “astronomical interferometry” that makes it possible to study very small details in the close surroundings of Mira stars. Ultimately, images of the observed stars can be reconstructed.
Mira stars, named after the first such known object, Mira (omicron Ceti), have been observed for more than 400 years by astronomers both professional and amateur. This class of variable red giants is famous for their pulsations that last for 80-1000 days and that cause their apparent brightness to vary by ten or more during a cycle at visible wavelengths. A possible explanation of their significant variability is that large amounts of material, including dust and molecules, are produced during each cycle. This material blocks the stellar radiation until the material becomes diluted by expansion. The close environment of Mira stars is therefore complex, and the characteristics of the central object are difficult to observe.
Jennifer Martin | alfa
Further Improvement of Qubit Lifetime for Quantum Computers
09.12.2016 | Forschungszentrum Jülich
Electron highway inside crystal
09.12.2016 | Julius-Maximilians-Universität Würzburg
Physicists of the University of Würzburg have made an astonishing discovery in a specific type of topological insulators. The effect is due to the structure of the materials used. The researchers have now published their work in the journal Science.
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A multi-institutional research collaboration has created a novel approach for fabricating three-dimensional micro-optics through the shape-defined formation of porous silicon (PSi), with broad impacts in integrated optoelectronics, imaging, and photovoltaics.
Working with colleagues at Stanford and The Dow Chemical Company, researchers at the University of Illinois at Urbana-Champaign fabricated 3-D birefringent...
In experiments with magnetic atoms conducted at extremely low temperatures, scientists have demonstrated a unique phase of matter: The atoms form a new type of quantum liquid or quantum droplet state. These so called quantum droplets may preserve their form in absence of external confinement because of quantum effects. The joint team of experimental physicists from Innsbruck and theoretical physicists from Hannover report on their findings in the journal Physical Review X.
“Our Quantum droplets are in the gas phase but they still drop like a rock,” explains experimental physicist Francesca Ferlaino when talking about the...
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