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
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20.04.2018 | ICFO-The Institute of Photonic Sciences
University of Connecticut researchers have created a biodegradable composite made of silk fibers that can be used to repair broken load-bearing bones without the complications sometimes presented by other materials.
Repairing major load-bearing bones such as those in the leg can be a long and uncomfortable process.
Study published in the journal ACS Applied Materials & Interfaces is the outcome of an international effort that included teams from Dresden and Berlin in Germany, and the US.
Scientists at the Helmholtz-Zentrum Dresden-Rossendorf (HZDR) together with colleagues from the Helmholtz-Zentrum Berlin (HZB) and the University of Virginia...
Novel highly efficient and brilliant gamma-ray source: Based on model calculations, physicists of the Max PIanck Institute for Nuclear Physics in Heidelberg propose a novel method for an efficient high-brilliance gamma-ray source. A giant collimated gamma-ray pulse is generated from the interaction of a dense ultra-relativistic electron beam with a thin solid conductor. Energetic gamma-rays are copiously produced as the electron beam splits into filaments while propagating across the conductor. The resulting gamma-ray energy and flux enable novel experiments in nuclear and fundamental physics.
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Stable joint cartilage can be produced from adult stem cells originating from bone marrow. This is made possible by inducing specific molecular processes occurring during embryonic cartilage formation, as researchers from the University and University Hospital of Basel report in the scientific journal PNAS.
Certain mesenchymal stem/stromal cells from the bone marrow of adults are considered extremely promising for skeletal tissue regeneration. These adult stem...
In the fight against cancer, scientists are developing new drugs to hit tumor cells at so far unused weak points. Such a “sore spot” is the protein complex...
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12.04.2018 | Event News
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20.04.2018 | Interdisciplinary Research
20.04.2018 | Physics and Astronomy