Astronomers: Many Sun-Like Stars Already Devoured Their Planets

You can tell a lot about a star by the lines of its spectral “fingerprint,” starting with what chemical elements it must be made of. From there, we can draw conclusions about lots of stellar phenomena, including how old a star is, how hot it’s burning, how fast it’s moving, and whether it’s due to explode. That’s how we figured out that Betelgeuse — one of Orion’s shoulders — is a baby rogue star doing its best to live fast and die young.

Our sun is not like Betelgeuse, thankfully. Just like the overwhelming majority of known stars, Sol is a nice quiet stable main-sequence star. Main sequence refers to the period of a dwarf star’s life when it’s fusing hydrogen into helium. As a main-sequence star ages, a cascade of reactions and explosions creates heavier elements, with some of the raw materials flung away into space at every step. The debris from this unbroken sequence creates a forensic record that reliably links a main sequence star’s color and composition to its temperature and age.

Stars born in the same place at the same time should be, in the authors’ words, “chemically identical.” If the stars in a pair are of different kinds, that can tell us a binary pair came about as a capture. Trace differences in stellar composition can even tell us what a star has eaten recently. Twin studies are important to science, and twin stars are no exception: Twins are also why the authors of this new study are able to so confidently assert these odds of planetary snackage. Based on how often they observed the presence of certain heavy elements in just one of the twins in a binary pair, the researchers estimated that up to one in three stars will eat “at least one” of their rocky planets.

“If a star is anomalously rich in iron but not in other elements such as carbon and oxygen, this can be interpreted as a signature of planetary engulfment,” explained lead study author Lorenzo Spina, an astrophysicist at the Astronomical Observatory of Padua. Furthermore, sun-like stars burn off their lithium pretty fast, but there’s lithium in the crust of planets – so lithium in an older star’s spectral signature is another tipoff that it may have consumed a planet. So too for metals, and silica from rock.

This all confirms our expectation of Sol eventually expanding to consume everything from Earth inward, right before it explodes into a planetary nebula. It could also help point us toward earthlike worlds outside our own star system.

It also means that there’s a timeline where one of the twin suns of Tatooine ate the planet long before Anakin could start whining about sand. And the only way anyone would know there ever was any sand is by staring straight at the system and noticing the barest glow of silica in the light of one slightly mismatched star. Just like Anakin would have wanted.

Continue reading

Chromebooks Gain Market Share as Education Goes Online

Chromebook sales have exploded in the pandemic, with sales up 90 percent and future growth expected. This poses some challenges to companies like Microsoft.

Review: The Oculus Quest 2 Could Be the Tipping Point for VR Mass Adoption

The Oculus Quest 2 is now available, and it's an improvement over the original in every way that matters. And yet, it's $100 less expensive than the last release. Having spent some time with the Quest 2, I believe we might look back on it as the headset that finally made VR accessible to mainstream consumers.

AMD Smashes Revenue Records as Zen 3, Xbox Series X, PS5 Ramp Up

AMD's Q3 2020 results are in, and the results are excellent for the company, in every particular.

MSI’s Nvidia RTX 3070 Gaming X Trio Review: 2080 Ti Performance, Pascal Pricing

Nvidia's new RTX 3070 is a fabulous GPU at a good price, and the MSI RTX 3070 Gaming X Trio shows it off well.