red dwarf
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One of the most anticipated ground-based telescopes ever built, the Vera Rubin Observatory in northern Chile is finally about to make a difference. Once the company’s wide-field camera detects science’s first light early next year, it will begin looking for optical signatures of supernovae millions or even billions of light-years away. .
This will allow theorists to better understand the nature of both dark energy (the unknown force accelerating the rate of expansion of the universe) and the effects of dark matter (the frightening and mysterious matter that constantly pervades our universe). It will help you. level.
During the observatory’s estimated 10-year initial period of operation, its Legacy Space-Time Survey (LSST) has also identified unusual phenomena that completely overturn current astrophysical understanding. You will.
What is a temporary celestial event?
In the strictest sense of the word, that’s new, SALT transient principal investigator David Buckley told me at the recent Rubin-era Cosmic Flow conference in Puerto Varas, Chile. Told. But transient really refers to anything that changes. It’s something that suddenly exists in a place we didn’t know anything about before, Buckley says.
Fast blue light transients (FBOT) are just one example.
According to Sullivan, fast blue light transients are incredibly bright phenomena that don’t last very long. They have been discovered in research and I believe they have explosive origins, he says. A typical supernova caused by the explosion of a white dwarf lasts several weeks and is about 10 billion times brighter than the Sun, Sullivan said. But FBOTS appear and disappear so quickly, he says, that astronomers don’t have much time to study them in detail and figure out what they are.
What is that?
Sullivan said there is a theory that supernovae occur inside the so-called circumstellar medium. This material is ejected during the star’s life, but remains near the star. And when a supernova explodes, it can collide with this ejected material. When you heat it up, it gets very hot and produces very bright transient events, Sullivan says.
It is expected that LSST will find hundreds of these FBOTs.
But the real trick to understanding what these objects are, Sullivan says, is being able to identify them in the data stream very early, very early on.
Actually catching a red dwarf
Rubin Observatory will also help researchers understand how stellar flares, primarily from M-type stellar red dwarfs, likely influence the origin of life in our universe.
The median timescale of these red dwarf flare events is about 30 minutes, making it impossible to predict when they will occur, said Riley, a graduate student in astronomy and physics at the University of Delaware in Newark.・Mr. Clark told me in his lecture. Same Puerto Varas conference. That makes them very difficult targets for most astrophysical investigations, Clark says.
Clark and his colleagues hope to use LSST to extract enough information from images of single flare events to be useful to researchers studying the stellar physics of these stars.
One possible way to do this, Clark said, is to use the refractive properties of the atmosphere to infer the temperature of a stellar flare based on how far the star moves across the sky during the event. It is said that Their position in the sky is determined by color, he says.
Differential chromatic refraction (DCR) is a refractive property of our atmosphere, Clark says, just as when you look at an object at the bottom of a pool, it appears distorted from its actual location. The atmosphere does the same thing for starlight, so when starlight passes through the atmosphere, it depends on the spectral energy distribution of the light source, he says.
When more light is emitted at shorter wavelengths, the light appears blue, Clark said.
During its 10-year extension, LSST is expected to detect about 3 million red dwarf flares that make the star’s surface an estimated 10,000 Kelvin hotter, or nearly 50 percent hotter than the Sun’s surface. It is this sudden increase in brightness that the Rubin Observatory should detect.
Understanding the mechanisms and frequency of such flare events goes beyond mere astrophysics. Many astrobiologists believe that red dwarfs, the most common stars in the universe, may be prime candidates for terrestrial planets that could potentially support life. If a particular star is prone to such flares, it may not be a candidate for a habitable planet.
Could these flares spark life on exoplanets orbiting such stars?
We don’t know for sure whether the ultraviolet energy from the flare acts as a catalyst for prebiotic life. It might just disrupt the chemistry so much that it starts to strengthen chemical interactions, Riley said.
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