All articles tagged with #stellar evolution
A new analysis of 155 binary black-hole mergers detected by LIGO/Virgo/KAGRA finds about 14% could be second-generation black holes formed from prior mergers, suggesting hierarchical mergers occur in dense stellar environments and can create unusually massive BHs in the 40+ solar-mass range, challenging simple stellar-collapse narratives and raising questions about their true origins.
New models of how aging stars interact with nearby planets suggest Earth could avoid being engulfed as the Sun swells into a red giant. The study finds that weaker tidal forces and mass loss from the Sun could allow Earth (and Mars) to migrate outward, while Mercury and Venus are still doomed to be swallowed. The outcome depends on uncertain mass-loss rates during the Sun’s final stages; with current data, Earth’s survival is possible but not guaranteed, and more observations of sun-like giants are needed, the team reports in Astronomy & Astrophysics.
New stellar-evolution models and observations of a nearby dying star suggest Earth could survive the Sun’s giant phases if solar mass loss dominates over tidal forces, allowing Earth to move outward rather than be engulfed. Mercury and Venus are still expected to meet a fiery end, but the outcome hinges on how much mass the Sun will lose—an uncertainty researchers are currently trying to resolve, with future missions like PLATO expected to help. A Letter to the Editor in Astronomy & Astrophysics outlines these calculations and the remaining questions about Earth’s ultimate fate.
New modelling suggests Earth might avoid engulfment by the Sun if solar mass loss dominates tidal dissipation; the planet could drift outward as the Sun expands into a red giant and finally a white dwarf, while Mercury and Venus are still likely to be swallowed and life on Earth would end due to rising luminosity.
A newly released image of the Crystal Ball Nebula captures the dramatic ejections from a dying star, revealing intricate shapes carved by stellar winds and offering fresh insight into the final stages of stellar evolution and planetary nebula formation.
New research models how a star capturing a primordial black hole (PBH) would evolve, finding that capture is most likely in three-body systems and leads to two possible fates: a rapid, disk-driven explosion (a Hawking-star) that destroys the star, or a slower, quasi-steady consumption that leaves a massive, high-spin remnant. The explosive path would produce multimodal electromagnetic signals (X-ray flash, UV/blue transient, possibly a low-luminosity GRB) while the quiet path could emit gravitational waves in the future. Observing these outcomes could constrain how much PBHs contribute to dark matter.
Astronomers report that the star WOH G64 in the Large Magellanic Cloud has transitioned from a red supergiant to a yellow hypergiant, with ongoing mass loss and heating—a potential sign it is nearing a supernova. The change may result from interactions with a companion or a pre-supernova wind, representing a short-lived but crucial phase in the evolution of a very massive star.
Using NASA’s TESS data from 2019–2024, astronomers identified TIC 120362137 as the most compact 3+1 quadruple star system: an eclipsing binary eclipsed by a third star, plus a distant fourth star with a 1,045.5‑day orbit—the shortest outer period observed in such a configuration. The inner three stars are packed within Mercury’s orbital distance while the outer companion sits near Jupiter’s orbit. The team’s models suggest the inner trio will merge into a white dwarf in ~300 million years, leaving a double white-dwarf system with a ~44‑day orbit.
Astronomers using NASA’s TESS have found TIC 120362137, the most compact known 3+1 quadruple star system: a tightly bound inner triple is orbited by a distant fourth star, with the outer companion about the distance of Jupiter from the Sun, while the inner trio would fit inside Mercury’s orbit. This rare architecture helps scientists study how such systems form and stay stable, and simulations predict the system will eventually merge into two white dwarfs in a ~44-day orbit, a scenario described in Nature.
Astronomers monitoring the red supergiant WOH G64 in the Large Magellanic Cloud report a rapid evolution into a yellow hypergiant, with a temperature rise of about 1,000 C and significant shrinking. This rare color and size change may signal an impending supernova, though researchers offer two possible explanations—binary interaction with a companion or a prior eruptive episode—and the star’s exact fate remains uncertain.
Astronomers may have observed the first superkilonova, a hybrid explosion involving both a supernova and a kilonova, suggesting new insights into star death and heavy element formation, though confirmation is pending.
Researchers used archival Hubble data to test axion models by examining white dwarf cooling rates, but found no evidence for axions, setting new constraints on their interaction with electrons and highlighting the need for more innovative detection methods.
Scientists using TESS data have observed that planets are becoming rarer around aging stars, likely due to the stars' expansion and tidal forces that cause planets to decay or be engulfed, providing insights into the future fate of our solar system.
Scientists have explained the 'impossible' merger of massive, rapidly spinning black holes by considering the role of magnetic fields in the evolution of progenitor stars, revealing that magnetic forces can influence black hole mass and spin, and potentially produce black holes within the mass gap observed in previous theories.
Astronomers captured the earliest image of a supernova, SN 2024ggi, just 26 hours after explosion using ESO's VLT, revealing its olive-shaped geometry and providing new insights into the explosion mechanics of massive stars.