Giant cavity discovered in the Milky Way

After at least one giant star exploded, astronomers discovered a giant cavity in the Milky Way surrounded by two nebulae, the clouds of Perseus and Taurus, according to a study published yesterday. The molecular clouds Perseus and Taurus, as they are called, have long been the subject of observations due to their proximity to the Earth, between 500 and 1000 light years, a negligible distance on the scale of our Milky Way galaxy, which is over 80,000 light years in diameter.

“The funny thing about these two clouds is that you can see that they are well connected, not as you imagine, but through a giant cavity,” researcher Shmuel Bialy told AFP. Harvard Center for Astrophysics and the Smithsonian Institution.

This is the first time that scientists have been able to design a three-dimensional map of such a structure, called the “Per-tau shell”, using advanced computational and imaging techniques, in particular a map of molecular gases in a larger area drawn using data from the Gaia Space Telescope. Bialy explained that one had to imagine a “sphere with an empty interior” or a “super bubble” with a diameter of about 500 light years (about 4.7 million billion km), and its outer atmosphere formed partly by the clouds Perseus and Taurus.

The interior of the cavity contains little dust, “but at a very low density compared to the density of clouds,” said German institute assistant professor Max Planck, astrophysicist and physicist Torsten Enslin.

Inslin participated with lead author Shmuel Bialy in the conduct of this study, the results of which have been published in the “Astrophysical Journal Letters”. He is one of the scientists who created in 2019 and 2020, the first 3D map of dust clouds near our sun. This happened thanks to Gaia’s data on the location and characteristics of more than five million stars in this solar “suburb”.

Catherine Zucker, postdoctoral researcher and astrophysicist, signed up for a second study on the subject to explain how scientists are making good use of this map, helped in part by algorithms developed under her supervision.

“This is the first time that we can use real 3D views, not simulations, to compare theory to observation and estimate what works best” to explain where this giant cavity and these clouds are. installed on its surface, Zucker said.