Astro News: Planet-eating Stars and an Accidental Brown Dwarf

An Accidental Discovery

Nearby brown dwarf moving through stellar field
The shifting object within the backside left nook of this animation of NEOWISE photographs is a brown dwarf formally named WISEA J153429.75-104303.3 and nicknamed “The Accident.”
NASA / JPL-Caltech / Dan Caselden

A citizen scientist has inadvertantly found a peculiar brown dwarf, formally referred to as WISEA J153429.75-104303.3 — however nicknamed “The Accident.”

Brown dwarfs, typically dubbed “failed stars,” radiate principally infrared relatively than seen mild. But whereas The Accident is vivid at some infrared wavelengths, it is surprisingly faint at others. Its brightness throughout wavelengths, or spectrum, did not match that of greater than 2,000 brown dwarfs already identified — in actual fact, that is why the article slipped by preliminary searches.

Citizen scientist Dan Caselden, a pc safety researcher who enjoys partaking with NASA’s Backyard Worlds: Planet 9 venture, discovered the brown dwarf by — you guessed it — accident. He had created his personal program to seek out objects shifting throughout the body. He was particularly searching for these whose colours matched these of identified brown dwarfs. But whereas he was taking a look at a kind of, he noticed The Accident flitting by.

Davy Kirkpatrick (Caltech) and colleagues printed a follow-up research on the article in Astrophysical Journal Letters. Based on further observations, they counsel that not solely has this brown dwarf cooled off, it is had loads of time to take action — 10 billion to 13 billion years, they estimate. As a consequence, it may need shaped earlier than there was a lot methane about; methane is what provides different brown dwarfs their attribute spectrum.

The workforce writes that the James Webb Space Telescope might present knowledge to verify or deny the dearth of methane, offering “verification, refutation, or further befuddlement.”

Read extra in NASA’s press release.

Some Stars Eat Their Own

Sibling stars ought to look alike, however some Sun-like stars that had been born in the identical gas cloud as their companions present sudden variations — maybe as a result of some stars eat their very own planets.

Star with planet
In the chaos of planet formation, some Sun-like stars might engulf their planets.ESA / ATG medialab

To perceive these chemical variations, Lorenzo Spina (INAF, Italy; Monash University and ASTRO-3D, Australia) led a workforce in inspecting pairs of Sun-like stars. In Nature Astronomy, they report that in 33 of 107 pairs, one of many stars has extra iron than anticipated (the opposite stellar pairs are all chemically an identical). Iron is a refractory factor that may survive engulfment by a star, and it is available in rocky planet cores.

Furthermore, the stars with greater iron abundances additionally had extra lithium. Stars destroy lithium in fusion reactions, however lithium is plentiful in planets, so this discovering additionally helps the planet-engulfment state of affairs.

Based on the pattern, Spina’s workforce discovered that a few quarter of Sun-like stars eat from their very own planetary buffet, talking to the chaos — and carnage — of planet formation.

Read extra from Spina at The Conversation.


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