“The R-Process Alliance aims to answer the big, unanswered questions related to decoding the mysteries of the oldest stars in the Milky Way–by bringing together an interdisciplinary group of observers, theorists, and experimentalists,” University of Michigan astronomer Ian Roederer wrote in an email to The Daily Galaxy, about the discovery of a relatively bright star HD 222925. The ancient object is a rare, ninth-magnitude star located toward the southern constellation Tucana, where astronomers have been able to identify the widest range of elements in its photosphere, more than in any star beyond our solar system.
“The luminous blue variable is a supermassive, unstable star,” said Yan-Fei Jiang, a researcher at the Flatiron Institute in New York City. Unlike our own smaller and steady-burning Sun, luminous blue variables (LBVs) have been shown to burn bright and hot, then cool and fade, only to flare up again. Because of its mercurial behavior, conventional one-dimensional models have been less than adequate at explaining their special physics.
Astronomers have found an explanation for the strange occurrence of massive stars located far from their birthplace in the disk of our Milky Way Galaxy: the secret seems to lie in the merging of medium-mass stars, specifically HD 93521, a Population I massive O-type star 3,000 light-years above the galactic plane that was ejected on a 39-million year journey either through dynamical interactions or a result of a supernova in a binary system.
“Finding old stars could also lead to the discovery of new planets. Maybe we can find some ancient civilizations around these old stars,” suggested astrophysicist, Wei-Chun Jao, research scientist at Georgia State University about the oldest stars developed in the early stage of the Milky Way’s formation, making them about eight to twelve billion years old. They’re found in the halo, a roughly spherical component of the galaxy that formed first, in which old stars move in orbits that are highly elongated and tilted, hinting at their age through their motion, rotation rate, and chemistry.
“This is really an origin story; for the first time we can explain how all nearby star formation began,” says astronomer and data visualization expert Catherine Zucker a NASA Hubble Fellow at the Harvard Center for Astrophysics and Space Science Institute about the discovery that Earth sits in a 1,000-light-year-wide void surrounded by thousands of young stars.
“The discovery of this exceptional globular cluster remnant will help refine models of the formation of the first stellar structures of the Universe,” astronomer Nicolas Martin told The Daily Galaxy about the discovery of a stellar structure known as C-19 uniquely comprising stars with extremely low metallicity. Recent studies suggest that planetary systems made up of terrestrial-type planets in compact, tightly-spaced orbits are most likely to form around lower-metallicity stars. Small planetary systems orbiting low-metallicity stars have been around a lot longer, and may be the earliest type of planetary system, making them an ideal place to search for life.