Stars Archives

January 16, 2025January 16, 2025 by Andy Tomaswick

Colliding Stars, Stellar Siphoning, and a now a “Blue Lurker.” This Star System has Seen it All

Triple star systems are more common than might be imagined – about one in ten of every Sun-like star is part of a system with two other stars. However, the dynamics of such a system are complex, and understanding the history of how they came to be even more so. Science took a step towards doing so with a recent paper by Emily Leiner from the Illinois Institute of Technology and her team.

January 14, 2025January 14, 2025 by Evan Gough

The Webb Shows Us Where Cosmic Dust Comes From

Concentric rings of dust form around the pair of binary stars named Wolf-Rayet 140. The dust is formed when the stellar winds from the stars slam into each other every few years. Image Credit: NASA, ESA, CSA, STScI, JPL-Caltech

Carbon-rich cosmic dust comes from different sources and spreads out into space, where it’s necessary for life and for the formation of rocky planets like ours. When astronomers aim their telescopes at objects in the sky, they often have to contend with this cosmic dust that obscures their targets and confounds their observations.

One reason the JWST was built is to see through some of this dust with its infrared vision and unlock new insights into astrophysical processes. In new work, the JWST was tasked with observing the dust itself.

November 26, 2024November 26, 2024 by Evan Gough

The Hubble and FU Orionis: a New Look at an Old Mystery

This is an artist's concept of the early stages of the young star FU Orionis (FU Ori) outburst, surrounded by a disk of material. A team of astronomers has used the Hubble Space Telescope's ultraviolet capabilities to learn more about the interaction between FU Ori's stellar surface and the accretion disk that has been dumping gas onto the growing star for nearly 90 years. NASA-JPL, Caltech

In 1936 astronomers watched as FU Orionis, a dim star in the Orion constellation, brightened dramatically. The star’s brightness increased by a factor of 100 in a matter of months. When it peaked, it was 100 times more luminous than our Sun.

Astronomers had never observed a young star brightening like this.

November 21, 2024November 21, 2024 by Evan Gough

The First Close-Up Picture of Star Outside the Milky Way

WOH G64 is a massive red supergiant star in the Large Magellanic Cloud. Thanks to the ESO's Very Large Telescope Interferometer, this is the first close-up picture of a star in another galaxy. Image Credit: ESO/K. Ohnaka et al.

Like a performer preparing for their big finale, a distant star is shedding its outer layers and preparing to explode as a supernova.

Astronomers have been observing the huge star, named WOH G64, since its discovery in the 1970s. It’s one of the largest known stars, and also one of the most luminous and massive red supergiants (RSGs). The star is surrounded by an envelope of expelled star-stuff, which could indicate it’s getting ready to explode.

November 20, 2024November 20, 2024 by Evan Gough

Main Sequence and White Dwarf Binaries are Hiding in Plain Sight

This ALMA image shows the binary HD101584. The pair of stars share a common envelope, and are surrounded by complex clouds of gas. Image Credit: By ALMA, CC BY 4.0, https://commons.wikimedia.org/w/index.php?curid=86644758

Some binary stars are unusual. They contain a main sequence star like our Sun, while the other is a “dead” white dwarf star that left fusion behind and emanates only residual heat. When the main sequence star ages into a red giant, the two stars share a common envelope.

This common envelope phase is a big mystery in astrophysics, and to understand what’s happening, astronomers are building a catalogue of main sequence-white dwarf binaries.

November 18, 2024November 18, 2024 by Evan Gough

Up to a Third of Stars Ate Some of their Planets

Ultra-short period planets can be engulfed by their stars. They may be responsible for differences in metallicity between sibling stars. Image Credit: NASA, ESA and A. Schaller

In recent years, astronomers have developed techniques to measure the metal content of stars with extreme accuracy. With that capability, astronomers have examined sibling stars to see how their metallicity differs. Some of these co-natal stars have pronounced differences in their metallicity.

New research shows that stars engulfing rocky planets are responsible.

November 5, 2024November 5, 2024 by Evan Gough

Habitable Worlds are Found in Safe Places

Illustration of Kepler-186f, a recently-discovered, possibly Earthlike exoplanet that could be a host to life. (NASA Ames, SETI Institute, JPL-Caltech, T. Pyle) — This is Kepler 186f, an exoplanet in the habitable zone around a red dwarf. We've found many planets in their stars' habitable zones where they could potentially have surface water. But it's a fairly crude understanding of true habitability. Image Credit: NASA Ames, SETI Institute, JPL-Caltech, T. Pyle)

When we think of exoplanets that may be able to support life, we hone in on the habitable zone. A habitable zone is a region around a star where planets receive enough stellar energy to have liquid surface water. It’s a somewhat crude but helpful first step when examining thousands of exoplanets.

However, there’s a lot more to habitability than that.

October 8, 2024October 8, 2024 by Mark Thompson

TESS Finds a Triple Star System that Could Fit within Mercury’s Orbit

This artist’s concept illustrates how tightly the three stars in the system called TIC 290061484 orbit each other. If they were placed at the center of our solar system, all the stars’ orbits would be contained a space smaller than Mercury’s orbit around the Sun. The sizes of the triplet stars and the Sun are also to scale. NASA’s Goddard Space Flight Center

TESS, the Transiting Exoplanet Survey Satellite has been on the lookout for alien worlds since 2018. It has just hit the news again having identified an extreme triple star system where two stars orbit each other every 1.8 days. The third component circles them both in 25 days – this puts the entire system within the orbit of Mercury with a little wriggle room to spare! To visual observers, it looks like a single star but the power of TESS revealed a flicker as the stars line up and pass one another along our line of sight. Eventually, the two inner stars will merge, triggering a supernova event!

September 19, 2024September 25, 2024 by Evan Gough

Plants Would Still Grow Well Under Alien Skies

This is an artist's illustration of the rocky super Earth HD 219134. It orbits a K-type star, a long-lived stable type of main sequence star. The light from K-type stars is different than the Sun's. Can Earth plants photosynthesize effectively near these stars? Image Credit: By NASA/JPL-Caltech - http://photojournal.jpl.nasa.gov/jpeg/PIA19833.jpg, Public Domain, https://commons.wikimedia.org/w/index.php?curid=41995148

Photosynthesis changed Earth in powerful ways. When photosynthetic organisms appeared, it led to the Great Oxygenation Event. That allowed multicellular life to evolve and resulted in the ozone layer. Life could venture onto land, protected from the Sun’s intense ultraviolet radiation.

But Earth’s photosynthetic organisms evolved under the Sun’s specific illumination. How would plants do under other stars?

September 18, 2024September 20, 2024 by Evan Gough

A Star Was Kicked Out of a Globular Cluster by an Intermediate-Mass Black Hole

The M15 Globular Cluster (aka. Great Hercules Cluster). Astronomers suspect the existence of one or more intermediate-mass black holes at its heart. Credit: NASA/ESA/HST

Astronomers have solid evidence for the existence of stellar-mass black holes and supermassive black holes. However, evidence for Intermediate Black Holes (IMBHs) is more elusive. Their existence remains hypothetical.

However, study by study, evidence is accumulating for IMBHs. The latest comes from the globular cluster M15, where a fast-moving star suggests the presence of something massive. Could it be an elusive IMBH?