Since its existence was confirmed in August 2016, Proxima Centauri B has been one of the most important objects of study for experts in planetary sciences. First, because this extrasolar world, located just 4.2 light years away, is the closest to Earth discovered to date . Also, because it has a mass slightly greater than that of our planet. But, above all, because it is in the so-called habitable zone of its system, a space in which liquid water could exist on its surface and, therefore, conducive to harboring life.
However, it is not all good news. Proxima Centauri, the star around which it orbits, from which it is only 7 million kilometers (the planet surrounds it in 11.2 days), does not resemble the Sun. Of this red dwarf, smaller and colder than the star King, emanates a jet of particles that exerts a pressure on the exoplanet two thousand times greater than that experienced by Earth. Over time, this phenomenon could have caused a kind of electromagnetic erosion capable of dismantling its atmosphere. This, in fact, would thus lose so much oxygen that water could not be formed in a liquid state. A Princeton University study published in 2017 in The Astrophysical Journal Letters addressed this issue and already warned that, in this way, the chances that life had developed in Proxima Centauri B were significantly reduced, at least as we know it.
A stellar flamethrower
In addition, this red dwarf has been classified as a blazing star, an object that experiences sudden increases in brightness throughout the electromagnetic spectrum and from which constant flares emanate. Well, a team of researchers coordinated by astrophysicists Meredith MacGregor and Alycia Weinberger, from the Carnegie Institution, in the USA, has discovered that in March 2017 a gigantic solar flare took place in Proxima Centauri thatmultiplied its brightness by a thousand for ten seconds. This was ten times brighter than any recorded on the Sun.
In an essay also published inThe Astrophysical Journal LettersThe scientists point out that, to determine this, they analyzed the data provided by the ALMA radio telescope, located in the Atacama desert in Chile. Thus, they found out that the flare was preceded by a less intense one. In total, the event lasted just a couple of minutes, but, as a consequence of it, Proxima B could have received a bath of radiation of high energy four thousand times greater than that which the Earth can receive when this type of outburst occurs in our system. This would greatly complicate the development of life in this extrasolar world. “This type of event could destroy its atmosphere, evaporate the oceans and sterilize the surface, which leads us to think that the habitability of an exoplanet is influenced by many factors, in addition to the fact that it is at the appropriate distance from its star”, MacGregor notes in a statement.
Referencia: Detection of a Millimeter Flare from Proxima Centauri. Meredith A. MacGregor, Alycia J. Weinberger et al. The Astrophysical Journal Letters, Volumen 855; número 1 (2018).
Images: Roberto Molar Candanosa – Carnegie Institution – NASA / ESO – M. Kornmesser
