Astronomers have created a detailed three-dimensional map of the Local Hot Bubble (LHB), the vast, low-density region surrounding our solar system. This bubble filled with hot, The eROSITA telescope, which operates as part of the Spectrum-Roentgen-Gamma (SRG) mission, has allowed astronomers to see the bubble with unprecedented clarity by observing X-ray activity from outside Earth’s geocorona.
The new map shows interesting temperature differences within the LHB, which have been attributed to stellar winds and supernova explosions. These events cause some areas of the bubble to expand, giving a more dynamic picture of its evolution. A special discovery is the identification of an “escape tunnel” directed towards the constellation Centaurus. This tunnel may be a connection to another superbubble in the galaxy formed by active young stars.
History of the local hot bubble
The presence of the LHB has been recognized for nearly five decades, and its origin is thought to be linked to supernova activity. Initial studies of the bubble were hampered by interference from X-ray emissions within the Earth’s atmosphere. However, the eROSITA telescope, launched in 2019, has now provided astronomers with the clearest X-ray data of the bubble. Michael Yeung, a researcher at the Max Planck Institute, said the eRASS1 data, which were collected during a period of low solar wind activity, provide the most precise view of the X-ray sky to date.
Mapping of the Milky Way’s hemispheres in approximately 2,000 regions has revealed differences in temperature between the galactic north and south, with the northern hemisphere being cooler. This finding indicates internal temperature inhomogeneity within the LHB.
A new interstellar tunnel and its implications
Along with variations in temperature, eROSITA data have revealed a previously unknown interstellar tunnel pointing toward the Centaurus constellation. This tunnel appears to connect the LHB to a hot gas corridor in the Milky Way, suggesting a large network of such tunnels in interstellar space.
The team also noted the presence of dense molecular clouds at the edges of the LHB, likely a remnant of the bubble’s formation. MPE scientist Gabriele Ponti emphasized that the Solar System lies at the center of this bubble, even though the Sun entered the LHB only a few million years ago – a brief moment in the Sun’s 4.6 billion-year history.
