Black hole blasts may transform ‘mini-Neptunes’ into rocky worlds

Scientists believe such planets would be heavier than the Earth.


According to the team of astronomers at the Harvard Gazette Center, the Milky Way was changed into rocky planets by outbursts created by the adjacent supermassive black hole.

For this study, scientists gathered data from recent exoplanet findings, as well as X-ray and ultraviolet observations of stars and black holes. They examined the environment around the closest supermassive black hole to Earth: the 4 million solar mass black hole known as Sagittarius A*.

Howard Chen of Northwestern University in Illinois said, “It’s pretty wild to think of black holes shaping the evolutionary destiny of a planet, but that very well may be the case in the center of our galaxy.”

Any object that falls into the black hole in occasional feeding frenzies will generate bright flares of X-ray and ultraviolet radiation. And X-beam telescopes, for example, NASA’s Chandra X-beam Observatory and ESA’s XMM-Newton, have seen proven splendid outbursts produced before, running from around 6 million years to a little more than a century back.

Scientists considered the impacts of this high-vitality radiation on planets inside 70 light-years of the dark opening that have masses in the middle of Earth and Neptune. They found that the X-ray and ultraviolet radiation would blast away a large amount of the thick gas atmosphere of such planets near the black hole. In some cases, this would leave behind a bare, rocky core. Such rocky planets would be heavier than the Earth and are what astronomers call super-Earths.

John Forbes, a co-author from the CfA, said, “We wondered what these outbursts from Sagittarius A* would do to any planets in its vicinity. Our work shows the black hole could dramatically change a planet’s life.”

Co-author Avi Loeb, also of CfA, said, “These super-Earths are one of the most common types of planet that astronomers have discovered outside our solar system. Our work shows that in the right environment they might form in exotic ways.”

According to scientists, this black hole impact may be one of the most common ways for rocky super-Earths to form close to the center of our galaxy.

Loeb said, “It is generally accepted that the innermost regions of the Milky Way are not favorable for life. Indeed, even though the deck seems stacked against life in this region, the likelihood of panspermia, where life is transmitted via interplanetary or interstellar contact, would be much more common in such a dense environment. This process might give life a fighting chance to arise and survive.”

There are considerable difficulties required to identify such planets straightforwardly. The separation of the Galactic Center (26,000 light a long time from Earth), the crowded area, and the obstructing of light by interceding dust and gas make it difficult to watch such planets.

In any case, these difficulties might be met by the next generation of extraordinary ground-based telescopes. For instance, looking for travels with future observatories like the European Extremely Large Telescope may identify proof for these planets. Another probability is looking for stars with strange examples of components in their air that have relocated far from the focal point of the cosmic system.

Journal Reference

  1. Chen, H., Forbes, J. C., & Loeb, A. (2017). Habitable Evaporated Cores and the Occurrence of Panspermia near the Galactic Center. ArXiv. DOI: 10.3847/2041-8213/aaab46


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