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The binary system of Alpha Draconis (also known as Thuban), a system visible even to the naked eye and well studied 270 light years away from us, is actually an eclipsing binary system. Eclipsing binary systems are those in which the two stars, from our point of view, eclipse each other, i.e. they pass one in front of the other. This surprised the same researchers who discovered this important feature using data from NASA’s TESS telescope.
The system is made by a primary star 4.3 times the size of the Sun, and a companion star probably half the size of the primary star.
“The first question that comes to mind is ‘How did we miss this?'”, says Angela Kochoska, a researcher at Villanova University in Pennsylvania who presented her findings at the annual meeting of the American Astronomical Society in Honolulu.
Probably this feature has never been detected until now because eclipses, being quite short (they last about six hours) can be easily lost from Earth and, being the star so bright, the thing appeared “hidden” also other space detectors. This is one of the brightest known eclipsing binary systems in which the two stars are widely separated and interact only gravitationally (they don’t exchange materials).
These systems are very important for astronomers because it is possible to measure their masses and dimensions with unprecedented accuracy.
Researchers have found that stars orbit every 51.4 days at an average distance that is slightly greater than the average distance between mercury and the Sun. From our point of view, however, neither is ever completely covered by its companion and so it is a partial eclipse.
A team of astronomers has studied in greater detail the jet of materials and gas that escapes from the black hole at the center of the galaxy Messier 87, or M87, the black hole that was so prominent last year when astronomers published the first ever image of such an object.
This supermassive black hole, with a mass of 6.5 billion times that of the Sun, is located 500 million light-years away from Earth and is characterized by a very powerful jet of particles that come out at very high energy and very high speed as they “bounce” before being sucked into the event horizon of the black hole itself. Researchers have studied this jet at various wavelengths of light, including X-rays, also using the Chandra Space Telescope.
The results confirm that these jets coming out of supermassive black holes can reach speeds close to that of light. This is the first time that the speed of an object emerging from a black hole is recorded using X-ray data, as explained by Ralph Kraft of the Center of Astrophysics | Harvard & Smithsonian (CfA) in Cambridge. In fact, to make precise measurements of the speed of these jets, you need sharp X-ray vision, something that probably, at the moment, only the Chandra telescope can allow.
These jets, also called “relativistic jets”, are made of materials that initially form part of the swirling growth disk that rotates around the black hole at the center of the galaxy. Part of this material falls inside the black hole while another part is redirected at very high speed, in the form of narrow beams with real jets, along the magnetic field paths of the black hole itself.
In calculating the speed of the black hole’s object at the center of the galaxy M87, the researchers obtained the first example of a phenomenon called “superluminal movement” which, only apparently, sees sections of this jet move at speeds greater than the speed of light. This is just an optical effect that happens when these jets, travelling at very high speeds close to those of light, point in our direction.
The jet seems to travel towards us almost as fast as the light it generates and this generates the illusion, even measurable, that the jet’s motion is faster than light itself.
Researchers have measured an apparent speed of 6.3 times that of light for the “node” of the nearest black hole jet (a “node” is a kind of brighter lump that forms along the jet due to the irregularity of its fall).
The LIGO observatory in collaboration with the Virgo observatory has captured the gravitational waves of another collision event that most likely is the fusion clash between two neutron stars.
The first data was collected on April 25, 2019 and the related study was then published in Astrophysical Journal Letters.
This is a “very interesting” binary system, as reported by Alberto Vecchio, director of the Institute of Gravitational Wave Astronomy at the University of Birmingham, because the sum of the masses of the two neutron stars is the highest ever observed in a binary system. So high that perhaps we could talk about a new class of binary systems of neutron stars, a class that is substantially different from the similar binary systems we have identified so far.
At the moment, however, it cannot yet be ruled out that one of the members of the system is in fact a black hole. This is the second time that two neutron stars orbiting each other during fusion are detected through the reception of gravitational waves. The first such detection took place in August 2017.
Unlike the first time, this time no light was detected but only the gravitational wave data that suggested that fusion led to the creation of a new object with “an unusually high mass,” as reported in the press release that appeared on the website of the English University.
The study was carried out in collaboration with researchers from the Virgo Observatory in Italy and the results were presented during the meeting of the American Astronomical Society in Honolulu.
After a six-year development, a team of researchers from the Department of Neurology at the Vienna Medical University announces a new ultrasound technique that can significantly improve brain performance, especially for people suffering from Alzheimer’s disease, Parkinson’s disease or multiple sclerosis. In these diseases, brain neurons are constantly lost and this leads to memory loss, speech and movement disorders, mood swings and classic Parkinson’s tremors.
The researchers, led by Roland Beisteiner, have developed a new method that would be, as described in the press release published by the Viennese University’s own website, “a world first.” The ultrasound technique is non-invasive and can reach all areas of the brain to activate neurons and regenerate functions otherwise lost. The method, called transcranial ultrasound pulse stimulation (TPS), allows to penetrate and stimulate all areas of the brain with ultrasound pulses that are delivered directly into the skull.
The procedure is painless and can be performed with the patient fully conscious. The pulse emitted by the device has a wavelength between 3 and 5 mm and a length of approximately 3 cm. The method requires an accurate map of the brain previously performed by magnetic resonance imaging.
Thanks to this “navigation system”, during the procedure the neurologist can identify on the screen where the impulse is to be delivered and generally perform the entire procedure very precisely, as Beisteiner himself states.
Unlike transcranial magnetic stimulation (TMS), this new method provides greater precision for deep brain activation.
A group of researchers has discovered that eggshells can help grow and repair human bones. The discovery, carried out by a team of researchers from the University of Massachusetts in Lowell, could be of great help for those patients who have suffered bone damage caused by illness or accidents.
The process, led by Professor Gulden Camci-Unal, sees the first phase of grinding eggshells. The resulting mass is then combined with a hydrogel mixture. This compound then serves to form a miniature frame on which bone growth can be triggered in the laboratory. These artificially created bones can then be used for bone grafts. To grow bones in the laboratory with this system, researchers use bone cells taken from the patient’s body and cultured in an incubator.
According to the researchers, the main quality of eggshells lies in the fact that their particles, which are mostly made of calcium carbonate, favor the growth and hardening of bone cells taken from the patient, something that in itself accelerates healing as well as the growth of the bone in the laboratory. Furthermore, the fact that the basic cells are taken from the patient’s body minimizes the risks of possible rejection of the immune system.
The same system, the researchers assure, could then be used to make teeth, tendons and cartilage grow also in the laboratory. Researchers, who have already filed a patent, predict that this system may prove to be very important, as Camci-Unal points out, according to which, among other things, eggshell particles could also be used as a vehicle to supply drugs or other substances such as proteins and peptides in the human body.
A group of researchers has discovered that ghrelin, already defined as “the hunger hormone” because it is responsible for transmitting hunger signals from the intestine to the brain, can improve memory.
This substance, produced in the stomach, binds to particular receptors of the vagus nerve, a nerve that connects the intestine to the brain. According to Scott Kanoski, senior author of the study, ghrelin helps the vagus nerve promote memory, at least in the laboratory mice on which the experiments were conducted.
By blocking ghrelin signaling in rats using a method called RNA interference, the researchers found that mice had worse results in episodic memory tests, tests that involve having to remember when something happened or where it is. In the case of these experiments, the rats had to remember where an object was located in a specific location.
Furthermore, when the ghrelin signal was interrupted through the vagus nerve, rodents tended to eat more frequently but consumed smaller amounts with each meal.
According to the researchers, this characteristic would also be related to the problem of reduced memory as “deciding to eat or not to eat is influenced by the memory of the previous meal,” as specified by Elizabeth Davis, the lead author of the study.
These findings could prove useful for improving memory capacity in humans.
A group of researchers confirms that a new method for detecting extrasolar planets using gravitational waves could be very useful indeed. Specifically, this method would apply to the identification of those exoplanets that orbit binary systems of white dwarfs, both in the Milky Way and in the nearby Magellanic Clouds.
The method is based on the observations of gravitational waves, something that would allow the LISA observatory, a space observatory consisting of three satellites whose mission should be launched in 2034, to detect planets with at least 50 land masses. To date, the techniques most used to identify extrasolar planets are those related to the planet’s transit system in front of their own star from our point of view and that which is based on the interception of the gravitational influence that the planet can have on its own star.
In the new article, which appeared in Nature Astronomy , Nicholas Tamanini, a researcher at the Max Planck Institute for Gravitational Physics in Potsdam, and Camilla Danielski, a researcher at the French Commission for Atomic Energy and Alternative Energy (CEA) in Saclay, state that the inherent limitations of these methods can be overcome by resorting to gravitational wave analysis.
As the same Tamanini explains, the LISA observatory will measure, after the launch of the mission, the gravitational waves of many thousands of white dwarf binary systems. However, if in the vicinity of these latter orbits a fairly large planet, the same gravitational waves will appear different and this change can be analyzed to acquire information on the planet, as well as its own presence.