A Sun-like star orbiting a black hole

`This is the nearest known black hole by a factor of 3, and its discovery suggests the existence of a sizable population of dormant black holes in binaries.`

480 parsecs => 1500 light years away.

DoneWithAllThat• 4 years ago

I’m not an academic so maybe this is normal but 20+ “authors” of a paper seems crazy to me.

TeMPOraL• 4 years ago

Seems to be common these days in astrophysics and particle physics, where you have many teams across multiple institutions collaborating on the research.

zh217• 4 years ago

It's actually quite normal for experimental and observational subjects, which is the case for this one. I believe the record is set by one with over 5000 authors - see https://www.nature.com/articles/nature.2015.17567 for details.

rrwo• 4 years ago

For some subject areas, this is normal. Everyone who contributed something to the research gets credit. (I think in Physics the authors are listed alphabetically as well.)

Contrast that with other areas where people who contributed significant amounts of work towards research often get omitted from the work.

I note this from experience as a former academic and being close friends/family with academics.

taubek• 4 years ago

For some science fields it is totally normal to have so many people working on the same paper/project.

gus_massa• 4 years ago

I've been in ~10 authors papers. They were a collaboration of two ~5 persons groups of different universities. Each group has a different method tuned for a similar topic, and the idea was to use both of them together to get a better result.

And our project is a "software only" project. Other projects have to build an experimental device, babysit the device during the experiment, cleanup the noisy experimental data, and then try to reach conclusion, so it's natural to need more authors.

maaaaattttt• 4 years ago

If the star is close enough I have a hard time imagining what is happening to its orbiting planets.

Did they "de-orbit" during the creation of the black hole? Or do the planets orbit the black hole as they were already orbiting the original star before that?

Does that mean you can have a mix of stars and planets orbiting another star? Could it even be possible that a star has planets and a star orbiting it AND the star orbiting it also has it's set of planets orbiting as well?

And what happens to the time on the planets once they orbit closer to the black hole?

So many (and apologies in advance if stupid) questions!

devoutsalsa• 4 years ago

Let's assume the Star A and the Black Hole B hole orbited each other when the black hole was Star B. If Star B collapsed into a black hole of roughly the same mass, I don't think Star A & its planets would be affected much at all in terms or orbits. Maybe the Star A system would have been fried when Star B went supernova, but the orbits I don't think would change all that much. It's like how people say Earth would continue orbiting the center of our solar system if our sun turned into a black hole, as the center of gravity would be the same.

Someone try this w/ Universe Sandbox & report back please :) => https://universesandbox.com/

chasil2• 4 years ago

"Star A" is nearly the mass of our sun.

When our sun exhausts the hydrogen in the core, it will swell as a red giant, encompass the orbits of Mercury and Venus, and likely come very close to earth.

"Black hole B" is currently ten times the mass of our sun. The star that produced it was likely much more massive still. The red giant phase of such a star might have reached to Neptune, so there is no way that these two evolved together.

When the star in this pair exhausts its hydrogen, the black hole will drain the red giant that it becomes.

jonhohle• 4 years ago

We have moons orbiting our planets orbiting our sun orbiting around the center of the Milky Way orbiting a larger galaxy… turtles all the way down.

ddevault• 4 years ago

I don't know the composition of this system or how feasible this arrangement would be given however the system may have evolved, but any planets could co-orbit the star and the black hole around their combined center of mass. They'd probably have to be relatively far away from both to be stable.

ilyt• 4 years ago

Did they "de-orbit" during the creation of the black hole? Or do the planets orbit the black hole as they were already orbiting the original star before that?

If the mass wouldn't change the orbit wouldn't chance much, they're still orbiting "same" mass.

But in most cases (AFAIK) creation of black hole involves supernova so, well, that ain't gonna be very healthy for the planet itself (lmao) and part of the mass would get ejected and orbits would get more elliptical

treeman79• 4 years ago

Death by neutrinos! https://what-if.xkcd.com/73/

three_seagrass• 4 years ago

They're not sure how the star came to be around the blackhole but it likely wasn't around when the blackhole was formed.

The mass of a star required to form the black hole would have swallowed this smaller star in it's formation.

Either way, it's challenging the current conceptions of how binary systems form/work.

throwaway4aday3• 4 years ago

Not sure if I got the masses right but using 9.62 solar masses and 0.92 solar masses for the black hole and the star respectively with a period of 185 days gives me a semi-major axis of 1.39 AU (using an orbital period calculator). If that's correct then this star is orbiting quite close to the black hole. Chances of it having any planets would be quite small although I suppose there could be planets orbiting the binary system at a large distance.

I don't speak astrophysicist but I think this part

Common envelope evolution can only produce the system’s wide orbit under extreme and likely unphysical assumptions. Formation models involving triples or dynamical assembly in an open cluster may be more promising.

means that the black hole and star formed separately and the black hole later captured the star? Hopefully the star had no life bearing planets before that, that would have been a terrible fate.

sulam2• 4 years ago

That’s how I interpret this as well.

n4r9• 4 years ago

the black hole later captured the star? Hopefully the star had no life bearing planets before that

That sounds like a decent sci fi novel idea: a civilisation racing to develop interstellar travel before a black hole grabs hold of its star and swallows its planet. How many months/years would it be from the star being captured to the planet being ripped away, I wonder? What would the experience be like for anything conscious on the planet?

chaosbolt• 4 years ago

Would the star's system orbiting the black hole change anything for its planets though? It's like with us, we barely care about Pluto let alone some distant object the sun and us as well are orbiting.

bArray• 4 years ago

At what point do they notice they are being captured? Depending on when this is set (relative to our own tech) and the relative speed at which their host star travels to the black hole, they could get little warning. The smaller the black hole (roughly planet size), I think the interesting it is, especially if it's on a collision course with earth.

I could imagine some engineer notices that some more distance probe from the star is suffering from clock skew, but nobody takes them seriously, putting it down to a fault in the circuitry: "It's old, the crystal timer is well out of spec". Then another distant probe also suffers a similar problem, and more people begin to take it seriously.

By the time they collect enough evidence that this is not by chance, other people have started to notice that stars have been vanishing behind a space in the sky. When asked why they didn't notice this sooner, there was no telescope pointed there for a while due to its position and budget cuts to the astronomy programme have limited search time.

Then the real drama begins, they know that amateurs will also notice soon enough, so they need to control the spread of information. They then need to somehow convince people who will most certainly die, along with everybody they know and love, and work towards the common goal of saving the human race.

Then some awesome science fiction around space travel that can escape black holes. Of course something will happen and the escape will be narrow, with them needing to sling-shot off the black hole or something.

I would call it something simple like "From Darkness" as not to spoil too much the story. For some reason Matthew McConaughey will be a space cowboy pilot, Amy Adams as space-travel Science officer, Matt Damon is chief potato grower and Denzel Washington has for some reason got to make a super hard decision to leave somebody behind. Samuel L Jackson will at some point get pissed off and force the launch. In a side story, Bruce Willis starts an expedition to go mine the black hole, and instantly gets noodled.

shagie2• 4 years ago

https://www.researchgate.net/publication/253117230_Science_F... - which may or may not have specific items in it that you're after, but they are on the harder side of science fiction within the topic.

I'd also suggest Crucible of Time by John Brunner, while it doesn't have black holes it does have an astronomical time pressure to it.

Flux is part of Stephen Baxter's Xeelee Sequence and again has an astronomical pressure. I'm gonna point out that this particular story has a lot of plot detained on Wikipedia with spoilers so... go there realizing that.

Continuing with Baxter and astronomical pressure... Raft (the first book of the Xeelee Sequence).

An honorable mention in this is another of the great Bs in science fiction his Gregory Before with the Galactic Center Saga... though it lacks the the same astronomical pressures that the other stories I've mentioned have.

cwillu• 4 years ago

Earth's orbit being disturbed fiction: A Pail of Air by Fritz Leiber and Perihelion Summer by Greg Egan

pyuser583• 4 years ago

That’s basically the plot of Three Body Problem.

Is suspect Netflix PR is somewhere lurking around.

jl6• 4 years ago

I'd probably take my chances on the planet rather than on a rush-job interstellar mission. My totally unquantified intuition is that the perturbation caused by the black hole arriving in the system is more likely to eject the planet into interstellar space than to cause it to intersect with either the star or the black hole. Even on an icy sunless de-atmosphered rock I think survival would be possible, living off the internal heat of the planet. The planet would become the interstellar mission.

Izikiel43• 4 years ago

I think there was an episode of stargate universe involving something like that.

ithkuil• 4 years ago

I recommend:

https://en.m.wikipedia.org/wiki/Incandescence_(novel)

CalChris• 4 years ago

If the black hole forms separately and then captures a star with an orbiting planet into an orbit, why could the planet not continue to just orbit the orbiting star? Wouldn't this be like a planet orbiting a binary star? There will be exceptional cases but it's not clear to me that the planet has to be consumed by the black hole without consuming the star.

pdonis• 4 years ago

A planet much closer to the star than the black hole is could possibly continue in an orbit fairly close to its previous one. But remember that the black hole is almost 10 times as massive as the star; that means that the hole is going to strongly perturb the orbits of any planets orbiting the star that weren't very close to the star. That doesn't necessarily mean the hole will consume such planets, just that their orbits will be very different than they were before, and might well become orbits around the hole, not the star.

twawaaay• 4 years ago

There is all sorts of possible orbits within the system. Both orbits very close to either BH or the star as well as orbits outside of the binary system orbiting both BH and the star would be very probable and stable.

There are more complex orbits possible but these would be more rare and possibly none of those could be stable over billions of years.

photochemsyn• 4 years ago

Nice zoom in video here, ending with display of orbit, and more discussion of why formation is strange:

https://interestingengineering.com/science/closest-black-hol...

"To elaborate, the star that died and turned into a black hole would have been at least 20 times as massive as the Sun. This likely means that it must have lived only for a few million years. But, if both stars formed at the same time, the gigantic one would have puffed up and swallowed the other star before it could become a "proper, hydrogen-burning, main-sequence star like our Sun". Or, if the star survived, it should have been on a much tighter orbit."

ars• 4 years ago

You may need to adjust for time dilation near the black hole.

means that the black hole and star formed separately and the black hole later captured the star?

That's why they say triplet. It's not actually possible for it to capture it directly without involving a third object.

The speed that the sun goes towards black hole is the exact same speed that it goes away from the black hole, the only way for it to be captured is for it to shed some speed into a third object.

That's why they're having trouble with the scenarios "unlikely" because it's not easy to do that.

Those types of capture is tend to produce extreme and very non-circular orbits. It's extraordinarily unlikely to capture a star and end up in a circular orbit.

karmakaze• 4 years ago

I'm not sure I understand the significance. Is it observation of something we'd expect anyway or something more.

All stars in the galaxy are orbiting a supermassive black hole at the center. So this is similar but on a much smaller scale. Maybe the find is illuminating early black hole interaction with nearby stars, idk.

ISL2• 4 years ago

Unless I'm now out-of-date, it is the first time a system quite like this has been observed. Quiet star quietly orbiting in a black-hole binary. Furthermore, it is very close to us on cosmological scales -- in our own galaxy, just over 1% of a galactic-diameter distant.

From this observation alone, one can directly sharpen up models not only of the probable number of BH-star binaries in the galaxy, but also models of the number of lonely black holes in the galaxy.

Forty years ago, this might have been a Nobel-winning discovery, as it would have provided new and compelling evidence for the existence of black holes (the dark partner can't be a neutron star because it is far too heavy). That story is now familiar to astrophysicists from many angles. This discovery is still one of the early remarkable results from Gaia -- that dataset is going to continue to shape our understanding of our neighborhood and our universe for decades to come.

It's very cool.

sulam2• 4 years ago

It’s not a typical binary. The money quote is 2/3 of the way down, essentially saying this is a bog standard G-type star with no obvious means to end up in this configuration that doesn’t involve complex interactions, up to and including a black hole wandering by and capturing the star (and probably sending all its planets spinning off into the universe).

Your typical binary like this is in close orbit, with far higher radial velocities (ie they are spinning like a top), and they show the effects of having been within shooting distance of the creation of their special friend (ie they got fried in a supernova).

pohl• 4 years ago

The title does bury the lede: this discovery is the closest confirmed black hole now. Before that, the closest was ~3000ly away.

There might be one ~960ly away, but that hasn't been confirmed.

https://en.wikipedia.org/wiki/List_of_nearest_known_black_ho...

Tepix2• 4 years ago

The paper is not yet on sci-hub.

arXiv link: https://arxiv.org/abs/2209.06833

soraki_soladead• 4 years ago

Is sci-hub still adding papers? I thought it was stalled because of a court case in India.

Regardless, if its on arxiv why use sci-hub?

Tepix2• 4 years ago

I think they started adding papers again.

Regardless, if its on arxiv why use sci-hub?

The version on arXiv is likely an earlier one.

exhilaration2• 4 years ago

We report discovery of a bright, nearby (G = 13.8; d = 480pc) Sun-like star orbiting a dark object.

Can anyone explain these two units - G and pc. I'm assuming d is distance? I've googled it but can't figure them out.

flebron• 4 years ago

pc = Parsec :) https://en.wikipedia.org/wiki/Parsec

I don't know what the G stands for. Possibly luminosity of some kind?

exhilaration2• 4 years ago

Brightness seems to be measured as apparent magnitude but that's denoted by m https://en.wikipedia.org/wiki/Apparent_magnitude

I think G is Stellar Classification https://en.wikipedia.org/wiki/Stellar_classification#Class_G which would mean this new star is the same class as our Sun.

captaincrowbar• 4 years ago

G is the apparent magnitude in the green part of the spectrum. Astronomers have a standardised set of optical bandpass filters to record the brightness of a star at various wavelengths - U (ultraviolet), B (blue), V (visual), G (green), etc. Using the letter ID of the filter to mean "apparent magnitude as seen through this filter" is a common convention.

DiogenesKynikos2• 4 years ago

G is for "Gaia," not "green." This is a wide band that covers most of the visible part of the spectrum.

See: https://www.cosmos.esa.int/web/gaia/iow_20180316

DiogenesKynikos2• 4 years ago

G refers to the apparent magnitude[0] in the main filter used by the European Space Agency's Gaia space telescope (one of the most important scientific missions going on right now, though the public is less aware of it than, say, JWST).[1,2]

pc refers to "parsec," a unit of distance approximately equal to 3.3 light years. Parsecs are a natural unit of distance, because a star that is one parsec away has a yearly parallax "wobble" of one arcsecond (not by accident - this is how the parsec is defined). Parallax is the fundamental way in which distances to nearby stars are measured, so parsecs are the natural unit to use. Every greater distance in astronomy is defined with reference to parsecs: kiloparsecs, Megaparsecs, Gigaparsecs, ...

0. https://en.wikipedia.org/wiki/Apparent_magnitude

1. https://en.wikipedia.org/wiki/Gaia_(spacecraft)

2. https://www.esa.int/Science_Exploration/Space_Science/Gaia

PicassoCTs• 4 years ago

Could life develop and survive in a green belt orbit around such a extreme system?

jayess• 4 years ago

What is a dormant black hole?

rsstack• 4 years ago

It isn't actively consuming new matter, which means it doesn't emit easily-visible radiation.

codethief• 4 years ago

A non-active one, i.e. without a significant accretion disk.

deathanatos• 4 years ago

My SO humorously proposes "Dyson Sphere" as the explanation for the dark companion mass.

phoe-krk• 4 years ago

After reading the title, my mind immediately created a headcanon that the black hole is Oracle and Sun is inevitably getting sucked in at some point.

Time to read the actual article, I guess. /s

A Sun-like star orbiting a black hole

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