Most studies of star formation—the “birth” of new stars—have been performed using static 2-dimensional photographs of star forming regions, or nebulae. Now, a new study using 3-D space motions that map stars in 3 dimensions of space, motion, and time astronomers have been able to generate a spatiotemporal map that reveales stars in our local region of the galaxy forming along the surface of an approximately 1000 light year wide bubble [1]. The stars in our “Local Bubble” are all moving away from a central point that appeared to form from several supernovae about 14 million years ago, which triggered expanding shockwaves that initiated condensation of interstellar gases into the discrete surface region of the bubble. The supernovae shockwaves—carrying all the heavy elements of the supernova metallogenesis—are responsible for triggering new star formation via the condensing of interstellar gases.
Astronomers have long theorized that supernovae could trigger this condensing by sweeping up gas into dense clouds that ultimately form new stars, but according to reports from the researchers involved in the latest study, they were surprised to learn that almost every single new star near the sun is forming on the surface of this Local Bubble.
Interestingly, the Sun is located nearly exactly at the center of the Local Bubble, although it wasn’t in the current central location when the supernovae occurred, it was at a safe distance from the supernovae emissions starting 14 million years ago. This observation and others have led astronomers to theorize that this similar structuring occurs throughout the Milky Way galaxy—in which there will be large voids surrounded by dense stellar formation surfaces, similar in patterning to the large-scale cosmological structure known as the cosmic web.
Researchers involved in the study believe that our Local Bubble may be interacting with other bubbles in our galactic neighborhood— new data from the Gaia mission, Gaia DR3, will help provide 3-D space motions for 30 million stars, expanding the spatiotemporal map beyond our Local Bubble to include adjacent stellar formation areas, and may reveal how this galactic patterning affects our solar system and others.
Reference
[1] C. Zucker et al., “Star formation near the Sun is driven by expansion of the Local Bubble,” Nature, vol. 601, no. 7893, pp. 334–337, Jan. 2022, doi: 10.1038/s41586-021-04286-5.
