Merging Stars Can Lead to Blue Supergiants

Artistic image of a binary system of a red giant star and a younger companion that can merge to produce a blue supergiant. Credit: Casey Reed, NASA

In the constellation of Orion, there is a brilliant bluish-white star. It marks the right foot of the starry hunter. It’s known as Rigel, and it is the most famous example of a blue supergiant star. Blue supergiants are more than 10,000 times brighter than the Sun, with masses 16 – 40 times greater. They are unstable and short-lived, so they should be rare in the galaxy. While they are rare, blue supergiants aren’t as rare as we would expect. A new study may have figured out why.

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Gaia Finds Ancient Streams of Stars That Formed the Milky Way

ESA’s Gaia space telescope discovered two star streams that helped form the infant Milky Way. Both are so ancient that they likely formed before even the oldest parts of our present-day galaxy’s spiral arms and disc. This image shows the location and distribution of Shakti (yellow) and Shiva (blue) stars throughout the Milky Way. Credit: ESA/Gaia/DPAC/K. Malhan.

Using ESA’s Gaia spacecraft, astronomers have tracked down two streams of stars that likely formed the foundation of the Milky Way. Named “Shakti and Shiva,” the two streams contain about 10 million stars, all of which are 12 to 13 billion years old and likely came together even before the spiral arms and disk were formed. These star streams are all moving in roughly similar orbits and have similar compositions. Astronomers think they were probably separate galaxies that merged into the Milky Way shortly after the Big Bang.,

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NASA’s VERITAS Mission Breathes New Life

Artist’s illustration of NASA’s VERITAS spacecraft in orbit around Venus. (Credit: NASA/JPL-Caltech)

In a win for planetary scientists, and planetary geologists in particular, it was announced at the recent 55th Lunar and Planetary Science Conference (LPSC) in Texas earlier this month that NASA’s VERITAS mission to the planet Venus has been reinstated into NASA’s Fiscal Year 2025 (FY25) budget with a scheduled launch date of 2031, with the unofficial announcement coming on the first day of the conference, March 11, 2024, and being officially announced just a few days later. This comes after VERITAS experienced a “soft cancellation” in March of last year when NASA revealed its FY24 budget, providing VERITAS only $1.5 million, which was preceded by the launch of VERITAS being delayed a minimum of three years due to findings from an independent review board in November 2022.

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Life Might Be Difficult to Find on a Single Planet But Obvious Across Many Worlds

This artist's illustration shows the exoplanet WASP-62B. Searching for chemical biosignatures on exoplanets is a painstaking process, weighed down by assumptions and prone to false positives. Is there a better way to find exoplanets with a chance to support life? Image Credit: CfA

If we could detect a clear, unambiguous biosignature on just one of the thousands of exoplanets we know of, it would be a huge, game-changing moment for humanity. But it’s extremely difficult. We simply aren’t in a place where we can be certain that what we’re detecting means what we think or even hope it does.

But what if we looked at many potential worlds at once?

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Brown Dwarf Pairs Drift Apart in Old Age

An artist's conception of a brown dwarf. A new study identifies CK Vulpeculae as the remnant of a collison between a brown dwarf and a white dwarf. Image: By NASA/JPL-Caltech (http://planetquest.jpl.nasa.gov/image/114) [Public domain], via Wikimedia Commons
An artist's conception of a brown dwarf. Brown dwarfs are more massive than Jupiter but less massive than the smallest main sequence stars. Image: By NASA/JPL-Caltech (http://planetquest.jpl.nasa.gov/image/114) [Public domain], via Wikimedia Commons

The only thing worse than drifting through space for an eternity is doing it alone. Observations with the Hubble Space Telescope show that brown dwarfs that once had companions suffer that fate. Binary brown dwarfs that were once bound to each other tend to drift apart as time passes.

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Dwarf Galaxies Could be the Key to Explaining Dark Matter

Dark matter map in Galaxy Cluster Abell 1689. Credit: NASA, ESA, and D. Coe (NASA JPL/Caltech and STScI)

If you have a view of the southern celestial sky, on a clear night you might see two clear smudges of light set off a bit from the great arch of the Milky Way. They are the Large and Small Magellanic Clouds, and they are the most visible of the dwarf galaxies. Dwarf galaxies are small galaxies that typically cluster around larger ones. The Milky Way, for example, has nearly two dozen dwarf galaxies. Because of their small size, they can be more significantly affected by dark matter. Their formation may even have been triggered by the distribution of dark matter. So they can be an excellent way to study this mysterious unseen material.

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An Asteroid Found Sharing the Orbit of Mars

The trojan asteroids of Mars. Credit: Armagh Observatory

Astronomers discovered another asteroid sharing Mars’ orbit. These types of asteroids are called trojans, and they orbit in two clumps, one ahead of and one behind the planet. But the origins of the Mars trojans are unclear.

Can this new discovery help explain where they came from?

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The Sound of an Interstellar Meteor Might Have Just Been a Rumbling Truck

Illustration of a fast blazing asteroid meteor over Earth
Illustration of a fast blazing asteroid meteor over Earth

A 2023 expedition to the Pacific Ocean, searching for debris from a suspected extraterrestrial object, may have been looking in the wrong place. A new look at the infrasound data used to locate the point of impact suggests that they may have been confused by the rumblings of a truck driving past.

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Webb Watches the Most Distant Galactic Merger Ever Seen

JWST shows details of massive galaxy merger 13 billion years ago. Credit: ASTRO 3D
JWST shows details of massive galaxy merger 13 billion years ago. Credit: ASTRO 3D

Astronomers know that galaxies form through mergers. They’ve been happening since the earliest epochs of cosmic time. Using the Webb telescope (JWST) astronomers found a massive merger of young galaxies going on about a half million years after the Big Bang. It’s called Gz9p3, one of the earliest and most distant mergers ever witnessed.

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Parker Solar Probe Was Blasted by Coronal Mass Ejections 28 Times in 4 Years

Artist's rendition of NASA's Parker Solar Probe. (Credit: NASA Goddard Space Flight Center)

NASA’s Parker Solar Probe (PSP) was launched on August 12, 2018, with the goal of becoming the first spacecraft to touch the Sun while teaching us more about our host star than any spacecraft or solar instrument in human history. Now, a recent study submitted to The Astrophysical Journal discusses the incredible data that PSP collected on coronal mass ejections (CMEs) over a four-year period. This study holds the potential to help scientists and the public better understand the CMEs and how they contribute to space weather.

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