A study published this weekend in the journal Monthly Notices of the Royal Astronomical Societyproposes that the oldest star in the Milky Way is a faint white dwarf that is about 10.7 billion years old and shining roughly 90 light years away from Earth.
The two planets are in circles that kind of look like, er….let’s just call the whole thing a cosmic donut (the outer “halo” is the protoplanetary disc of gas and dust from which planets eventually coalesce).
We already know that more than one object can share the same orbit; Jupiter has a collection of 120,000 asteroids following its same path around the Sun, for example. Earth has one, too. But although it’s theoretically possible, astronomers have never discovered two whole planets sharing the same orbit around a star before.
Hmm…the language here is a bit misleading. The two objects are technically not both “planets.”
The article comments later on that the object in the dotted line circle is “a cloud of debris about twice the mass of our Moon trailing a bit behind the innermost gas giant” in one of its LaGrange points (where “Trojan” asteroids follow gas giants such as Jupiter and Saturn). So it’s way too early to say that “two” planets formed in the same orbit.
Still, this is the first time that astronomers have spotted two such objects this close to one another in the same orbit. Who knows if both will remain viable (the debris cloud could become partly or mostly absorbed by the gas giant with the rest either being expelled or thrust into separate orbits).
So why is this called a “cosmic unicorn”?
Apparently because although such Trojans “are allowed to exist by theory, but no one has ever detected them.”
Um. OK.
So, like, totally NOT at all like this? Kind of a bummer, really…
The link below includes a night sky in Montana, which makes little sense when the researchers were in Beijing and Honolulu…
“The first-generation star we observed has the potential to become the oldest star we have ever seen,” said Alexander Heger, a professor in the school of physics and astronomy at Monash University in Australia who was part of the research team. “It probably had only lived for 2 1/2 million years and then exploded.”
Oh, and it also was discovered to be 260 times the size of our own Sun…just as theorized.
More importantly, this involved scientists from three different countries (China, Japan, and Australia), sharing information and working together for science.
Imagine if that spirit of cooperation could be extended into other domains…
Betelgeuse, the closest red giant to Earth, has long been understood to move between brighter and dimmer in 400-day cycles. But from late 2019 to early 2020, it underwent what astrophysicists called “the great dimming”, as a dust cloud obscured our view of the star.
Now, it is glowing at 150% of its normal brightness, and is cycling between brighter and dimmer at 200-day intervals – twice as fast as usual…It is currently the seventh brightest star in the night sky – up three places from its usual tenth brightest.
Betelgeuse is the closet red giant Star to our solar system, one of the shoulders of the Greek constellation of Orion.
The cultural information in the linked article was actually more interesting than the phenomenon observed. For instance, the fact that an Aboriginal people in Australia saw it long before the Greeks did was something I didn’t know.
And that the Greek name comes originally from the Arabic “bat al-jawzāʾ” meaning “giant’s shoulder.”
And all three cultures saw the star as connected with fire held by a giant hunter of some sort.
And so have ancient Babylonians, Egyptians, and probably everyone else, too. We just can’t help personifying even the stars.
The kicker?
When it does eventually explode, it could – over the course of a week – grow so bright that it will be visible during daylight, and cast shadows at night.
Now that’s something I’d like to be around to see. Hmm. If only I could manage to live for another 10- to 100,000 years…
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