Astronomers have discovered a star that appears to have engulfed around 15 Earth masses worth of rocky planets (not gas giants):
In mythology, the Titan Kronos devoured his children, including Poseidon (better known as the planet Neptune), Hades (Pluto) and three daughters. So when a group of Princeton astronomers discovered twin stars, one of which showed signs of having ingested a dozen or more rocky planets, they named them after Kronos and his lesser-known brother Krios. Their official designations are HD 240430 and HD 240429, and they are both about 350 light years from Earth.
The keys to the discovery were first confirming that the widely separated pair are in fact a binary pair, and secondly observing Kronos' strikingly unusual chemical abundance pattern, explained Semyeong Oh, a graduate student in astrophysical sciences who is lead author on a new paper describing Kronos and Krios.
[...] Other co-moving star pairs have had different chemistries, Oh explained, but none as dramatic as Kronos and Krios. Most stars that are as metal-rich as Kronos "have all the other elements enhanced at a similar level," she said, "whereas Kronos has volatile elements suppressed, which makes it really weird in the general context of stellar abundance patterns." In other words, Kronos had an unusually high level of rock-forming minerals, including magnesium, aluminum, silicon, iron, chromium and yttrium, without an equally high level of volatile compounds — those that are most often found in gas form, like oxygen, carbon, nitrogen and potassium.
[...] Oh and her colleagues calculated that gaining this many rock-forming minerals without many volatiles would require engulfing roughly 15 Earth-mass planets. Eating a gas giant wouldn't give the same result, Price-Whelan explained. Jupiter, for example, has an inner rocky core that could easily have 15 Earth masses of rocky material, but "if you were to take Jupiter and throw it into a star, Jupiter also has this huge gaseous envelope, so you'd also enhance carbon, nitrogen — the volatiles that Semyeong mentioned," he said. "To flip it around, you have to throw in a bunch of smaller planets."
While no known star has 15 Earth-sized planets in orbit around it, the Kepler space telescope has detected many multi-planet systems, said Jessie Christiansen, an astronomer at the NASA Exoplanet Science Institute at the California Institute of Technology, who was not involved in the research. "I see no problem with there being more than 15 Earth masses of accretable material around a solar-type star." She pointed to Kepler-11, which has more than 22 Earth masses of material in six planets with close orbits, or HD 219134, which has at least 15 Earth masses of material in its inner four planets.
(Score: 2, Funny) by EEMac on Monday October 16 2017, @01:25PM (3 children)
Am I the only one who thought: big round ball + eating dozens of crunchy small round pellets = Pac Man?
(Score: 2, Informative) by Anonymous Coward on Monday October 16 2017, @01:38PM
Yes.
(now mod me informative if you can)
(Score: 2) by bzipitidoo on Monday October 16 2017, @04:18PM
I thought of Cookie Monster. Particularly the "Crumby picture" intro of his movie parodies that show a greater than planetary sized Cookie Monster eating a planet sized cookie, against a background of stars.
(Score: 2) by nobu_the_bard on Monday October 16 2017, @04:57PM
I was thinking Galactus. He appears in a form you can comprehend. Maybe all we can comprehend is a big rock. Is that a step up from a really big man in purple armor? I don't know.
(Score: 0) by Anonymous Coward on Monday October 16 2017, @01:39PM
no. known in Roman mythology as "Neptune", and Greek mythology as "Poseidon".
god of the sea. big magic trident. same person. not a planet.
princeton.edu? I'm still happy for my friend who's doing a postdoc there, because he's actually working with smart people, but suddenly "princeton" doesn't mean all that much to me anymore.
(Score: 0) by Anonymous Coward on Monday October 16 2017, @01:43PM
Now, get there, cool it down (and store the energy in some shipstones) then mine the hell out of it.
(Score: 0) by Anonymous Coward on Monday October 16 2017, @03:27PM
Kolob tastes like chicken."
(Score: 2) by frojack on Monday October 16 2017, @07:08PM (1 child)
When a star eats its planets, nothing happens fast. One does not THROW a planet into a star.
Where will the gaseous envelope go? Will it go into the star, or pushed out into space by the horrendous stream of radiation?
See MAVEN Mission [nasa.gov]
Even if the gas giant was slowly sucked into the star, the gaseous atmosphere would be first sucked in, burned, probably almost instantly, followed by the much heavier core.
So this imbalance of elements may be a strictly temporal thing, and it might have looked different earlier in the process before the atmosphere was burned in the star.
No, you are mistaken. I've always had this sig.
(Score: 2) by takyon on Monday October 16 2017, @08:53PM
Elements heaver than hydrogen would not be "burned" (fused) in the star until later in the star's evolution.
Some gases from a rocky exoplanet might be blown away by the star instead of getting sucked in, but that shouldn't happen as much with a gas giant that has more gravity and gas.
[SIG] 10/28/2017: Soylent Upgrade v14 [soylentnews.org]