The solar system shines in the middle of a distinctly empty region of space.
This region of low-density hot plasma stretches for about 1,000 light-years and is surrounded by a membrane of cold, dense neutral gas and dust. It is called the local bubble and was a very difficult puzzle to solve, exactly how and why it appeared, why the solar system is in the middle of it.
Recently, a team of astronomers at the Harvard-Smithsonian Astrophysical Center compiled a more accurate map of the local balloon at this time and determined that the local balloon was probably “cut out” in a series of supernova explosions millions of years ago.
Previous studies have shown this, but now additional details have been revealed: the local bubble, which is still in the process of expansion, is causing an increase in star formation around its perimeter.
“It’s a really original story; “For the first time, we were able to explain how the formation of all the nearby stars began,” said study author Catherine Zucker, an astronomer at the Space Telescope Science Institute.
The local bladder was discovered not so long ago, in the 1970s and 1980s, by combining optical, radio, and X-ray observations. Gradually, these observations revealed a huge region that is about 10 times less dense than the average rate of interstellar space in a deer leap.
Since we know that supernovae can “cut out” gaps in space, as they expand outward to disperse gas and dust from there, this seemed like a reasonable explanation for the local bubble.
But it turned out to be more difficult to figure out how and when. First of all, it is difficult to measure the dimensions of the region of the space when you are in it; And it is doubly difficult to measure emptiness (voids) when it is surrounded by dazzling stars and other cosmic objects.
Zucker and his team used Gaia’s latest data to map gas and young stars within a radius of 650 light-years around the Sun. Gaia is an ongoing project of the European Space Agency, which accurately records the positions and movements of deer leaping stars.
As a result, it was found that all the new stars and star-forming regions are on the “surface” of the local bubble.
It is logical. When a supernova expands outward, it strikes and shrinks the matter in which it expands. Thus dense nodules of molecular gas are formed, which tangle in interstellar space, gradually collapsing under their own gravity and forming infant stars.
After that, the researchers conducted simulations and calculated the past locations of the star-forming regions to create a model of bladder expansion. As a result they were able to reconstruct its history to match their calculations on a bubble map.
The balloon’s history was found to begin about 14.4 million years ago, first with the birth of stars, followed by massive, short-lived supernova explosions of stars.
“We calculated that 15 supernovae that exploded over millions of years formed a local bubble like the one we see today,” explains Zucker.
Its radius is currently 538 light-years and is still expanding outward, but relatively slowly, at a speed of about 6.7 kilometers per second.
I wonder why the solar system is in the middle of it? This is purely coincidence.
“When the first supernovae that created the local bubble exploded, our sun was far from our area of action. “But about five million years ago, on its way to its own galaxy, the sun fell into exactly this bubble, and now, quite by accident, it is almost exactly in the center of the bubble,” said Juan Alvis, an astronomer at the University of Vienna.
According to the researchers, this indicates that deer leaps are more likely to be filled with such bubbles because the probability of such processes is so low that the bubbles are rare. This idea presents a deer leap in a sea-like structure, or a flat slice of Swiss cheese.
The next step is to discover other such bubbles. Their locations, dimensions, shapes, and interactions with each other may be the key to giving us better information about the evolutionary history of star formation and deer leap.
The following data from Gaia, which we will receive at the end of the year, should be very useful for this.