The magnetic field of the “local bubble” has been detected in 3D for the first time

The local bubble. It’s the name that Astronomy scientistsAstronomy scientists Give some kind of envelope about 1000 light yearslight years that surround us solar system. It is known to have been created by several explosions of massive stars in supernovae. a few million years ago. And as its surface is concentrated GasGas And dust, stars are born there. Recently, astronomers were able to map it (see article below). Today, some Researchers at the Center for Astrophysics at Harvard University (United States) unveils a new 3D image. that sound magnetic fieldmagnetic field.

Note that Milky Way It looks a bit like a piece of Emmental. With many wonderful cosmic bubbles that are similar to our local bubble. So learning more about the Local Bubble should allow astronomers to better understand the evolution and dynamics of these fascinating bubbles. But also its impact on the birth of stars and, more broadly, on the shape of large galaxies.

Better understanding of the role of magnetic fields

convinced that magnetic fields They play an important role in many astrophysical phenomena, and the researchers combined data from several space missions (JayaJaya And plankplank) to observe the polarization of light in our surroundings solar systemsolar system. Polarization caused by magnetically aligned dust particles. Which betray the direction of the magnetic field acting on it.

From the 2D map they obtained, the researchers turned to 3D on the assumption that most of the interstellar dust producing the observed polarization is on the surface of the Local Bubble and theories that predict that the magnetic field will be “rush” in the surface of the bubble when it expands true. “As technology and our understanding physicalphysical Improvement, we can improve the accuracy of our map and hopefully confirm what we’re seeing.”explains Alyssa Goodman, an astronomer at Harvard University communication. But already, astronomers can begin to investigate the effects of magnetic fields on star formation in superbubbles and a better understanding of how these spheres influence many other cosmic phenomena.

We are passing through a huge gas bubble on the surface of which stars are forming

Our solar system zips through a particularly empty region of space. It is surrounded by a local bubble, as astronomers call it. And today they tell us how this bubble was formed. After the explosion of several supernovae.

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Article from Natalie MeyerNatalie Meyer Posted on 01/16/2022

For decades, astronomers have known that it exists around our solar system, like a giant bubble. a “local bubble” which still measures about 1,000 light-years in diameter. Today, some researchers from Harvard and STScI (Space Telescope Science Institute) Report found everything The smallest stars around us It lies exactly on the surface of this bubble. All younger stars, but also many and a few star formation regions cloudsclouds Molecules – these are dense regions in which stars can successfully form – are well known. Through these observations, these astronomers are telling the story of this strange bubble.

Do you know ?

The existence of our Local Bubble was revealed in the 1970s and 1980s by observations in optics, radio waves and X-rays, and showed that the small corner of the Milky Way is about ten times thinner than the average.

It all began approximately 14.5 million years ago. with a training phasestarstar very strong. Then with a stretchSupernova explosion of fifteen massive stars. A series of explosions that began to eject interstellar dust and gas. It leaves us in a low-density area. It further gives rise to a bubble-like structure, the surface of which has the properties just right for star formation.

According to astronomers, this local bubble is still expanding today. for one SpeedSpeed 6.5 kilometers per second. It is equal to 23,400 kilometers per hour. High speed on our scale. But speaking of an astronomical phenomenon, the researchers believe we have a local bubble “I lost a punch”. It has practically reached a plateau.

Other bubbles in the Milky Way?

To rewrite the history of this amazing bubble, astronomers have drawn on several tools. Forms SupernovaSupernovafollower movementsmovements Excellent – according to data from European space mission Gaia — or even 3D maps of the material that surrounds our local bubble.

The researchers point out that it is our happy coincidence sunsun Right now it’s almost in the middle of this bubble. result of his journey through Milky Way. He drove it there about 5 million years ago now. Evidence, according to astronomers, that this type of structure must exist elsewhere in our galaxy. Because if these giant bubbles are rare, it is statistically unlikely that we will ever find ourselves in the heart of one.

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our Milky WayMilky Way So it will look a bit like cheese with holes. Holes – bubbles – excavated by dying stars and supernovae and at the edges of which one can observe newborn stars. It now remains only for the researchers to map a few of these bubbles. To determine its shape and size as well as its location. And why not, their interaction methods. A new way to understand the role end-of-life stars play in star formation, but also in the evolution of galaxies.

Who created the local bubble, Where is the Sun? supernovae…

It was highlighted during the 1970s that the local bubble in which our sun and its planets are currently moving may have been formed as a result of the successive explosion of multiple supernovae, firefire Cosmic fireworks that occurred about 10 million years ago. However, another explanation is possible: interchange fees solar windsolar wind With neutral gases from the interstellar medium. To decide between them, a team of researchers has developed a specific tool. The result: strengthening the supernova hypothesis.

Article from Xavier DemmersmanXavier Demmersman Posted on 09/09/2014

As we recently reported, according to a study that made the front page of natureOur galaxy, the Milky Way, in which we live, belongs to A sub-continentsub-continent The galaxy named by its discoverers Laniakea (“Enormous Heavenly Horizons” in the Hawaiian language). So much for a very large scale drawing. In more modest proportions, our Sun is currently evolving within one of its lobes AstrophysicistsAstrophysicists Calls since the spotlight in the seventies and eighties the “local bubble”.

With an estimated length of 300 light-years, its shape is similar to that of a PeanutsPeanuts or an hourglass. Its density is very low (0.001 atoms per cubic centimeter) and the temperature of the gases is particularly high in all directions, as shown by the first observations in X-rays.

A large number of supernovae

To explain these cavities in interstellar mediumthe proposed main scenario is a series of supernovae. Remember that such explosions of stars of incredible power (the energy spread out can exceed that developed by the Sun for a few million years) are not uncommon in the Milky Way. Astronomers estimate that in our galaxy, there is one galaxy every fifty years, on average. If many of us have escaped (as far back as 1604, the Kepler supernova was the last observed supernova in our galaxy), it is mainly because stars and dust are obscured from the galactic disk.

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However, it was completely different in our area 10 million years ago. In fact, many members of the massive star cluster appear to have popped like popcorn, leaving behind huge residual bubbles that continue to expand even today! This should happen at a reasonable distance from Earth, because we biospherebiosphere He didn’t seem to have experienced potential shock waves, and he didn’t show it stigmastigma for this period.

The supernova appears to have created the bubble

The hypothesis of the local bubble excavated by the explosion of stars is not unanimous in the scientific community. Scott Porter, one of the authors of the article published this summer in nature (July 27, 2014 issue), “Over the past decade, researchers have challenged the interpretation of supernovae, proposing that most, if not all, of these soft X-rays are the result of charge exchange.”. freight barter? For them, these are waves of electrically charged particles emitted by our star ( solar wind) on neutral gas shores, because the flares observed in the X-ray range produce the same effect as the ancient supernova remnants.

Also, to decide on the two suggestions and shed light on this topic, the researcher collaborated with Massimiliano Galeazzi (University of Miami) and his team to develop a sensitive detector for this topic. wavelengthwavelength, is able to distinguish between the two signatures. The baby was named at an altitude of about 275 km on December 12, 2012 DXL (Diffuse X-ray emission from the local galaxy) spent just five minutes in space before returning to Earth, loading up on valuable data on charge exchange in the solar system. Finally, after several months of searching, about 40% appears to be of solar origin. So ancient supernovae will be responsible for everything else.

“This is an important discovery.” Because it touches, concludes Professor Glazie “Our understanding of the region near the Sun can therefore be used as a basis for future models of the structure of our galaxy.”. Together with the new measuring instruments, DXL is supposed to make its next leap into space in December 2015.

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