Recent findings published in the journal Monthly Notices of the Royal Astronomical Society reveal the presence of some of the earliest stars in the halo of the Milky Way, surrounded by a galactic disk. These ancient stars, located just 30 thousand light years from Earth, have ages ranging from 12 to 13 billion years, approximately corresponding to the age of the oldest known stars.
The data for this groundbreaking discovery was collected using the Magellan-Clay Telescope Observatory Las Campanas. These stars exhibit low metal content, specifically in elements like strontium and barium, similar to stars previously found in ultrafaint dwarf galaxies, which are among the oldest galaxies thought to have contributed to the formation of the Milky Way.
In a separate discovery in 2022, the RELICS team identified EARANELLA, the most ancient known star, made visible through the manipulation of space-time to enhance views of distant regions of the Universe. This star, also low in metal content, became visible through the gravitational lensing effect caused by the galaxy cluster Whl0137-08.
Further investigation revealed that these ancient metal-poor stars are moving in a direction opposite to the majority of stars in the Milky Way. The team identified an additional 65 stars exhibiting similar characteristics. Astrophysicist Anna Frebel from the Massachusetts Institute of Technology remarked, “These stars are moving very rapidly – hundreds of kilometers per second – in the opposite direction. They appear to be fleeing! The reason behind this phenomenon remains unknown, adding a new dimension to the mystery.”
Future research will involve analyzing the orbital paths of these newly discovered stars to determine if their movements defy the overall motion of stars within the Galaxy. This investigation aims to shed light not only on the timescale of star evolution but also on the process of galactic formation. The James Webb Space Telescope will play a crucial role in this study, with its infrared capabilities enabling scientists to peer through the dense dust clouds of the Milky Way and unveil otherwise elusive celestial sources.