[HN Gopher] A Sun-like star orbiting a black hole
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A Sun-like star orbiting a black hole
Author : taubek
Score : 120 points
Date : 2022-11-08 12:33 UTC (10 hours ago)
(HTM) web link (academic.oup.com)
(TXT) w3m dump (academic.oup.com)
| maaaaattttt wrote:
| 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 wrote:
| 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/
| chasil wrote:
| "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.
| mr_toad wrote:
| > When the star in this pair exhausts its hydrogen, the
| black hole will drain the red giant that it becomes.
|
| I wonder if the accreting matter might undergo fusion.
| pmontra wrote:
| Disclaimer: I can't make any calculation but... Wouldn't
| Star A keep orbiting Star B inside the surface of Red Giant
| Star B, which wouldn't be very dense at the radius of the
| orbit? There is drag but a lot of inertia. Star A would
| start from further away than now. It would probably get
| some extra mass in the process, absorbing the gas of the
| red giant.
| chasil wrote:
| Here is an interesting variant on this concept.
|
| https://en.wikipedia.org/wiki/Thorne%E2%80%93%C5%BBytkow_
| obj...
|
| The drag will lead to orbital decay.
| pmontra wrote:
| Thanks. The time frame is only hundreds of years.
| ilyt wrote:
| > 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 wrote:
| Death by neutrinos! https://what-if.xkcd.com/73/
| jonhohle wrote:
| 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.
| three_seagrass wrote:
| 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.
| ddevault wrote:
| 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.
| exhilaration wrote:
| _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.
| DiogenesKynikos wrote:
| _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
| captaincrowbar wrote:
| 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.
| flebron wrote:
| pc = Parsec :) https://en.wikipedia.org/wiki/Parsec
|
| I don't know what the G stands for. Possibly luminosity of some
| kind?
| exhilaration wrote:
| 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.
| PicassoCTs wrote:
| Could life develop and survive in a green belt orbit around such
| a extreme system?
| wwarner wrote:
| `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.
| throwaway4aday wrote:
| 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.
| n4r9 wrote:
| > 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 wrote:
| 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.
| azernik wrote:
| More likely than "swallowing the planet" is disrupting
| orbits, sending the planet either flying off into deep dark
| cold space or onto some uninhabitable orbit around the
| star.
| shagie wrote:
| Kurzgesagt - What If Earth got Kicked Out of the Solar
| System? Rogue Earth - https://youtu.be/gLZJlf5rHVs
| akiselev wrote:
| If the black hole formed while in the system, the resulting
| radiation would wipe out all life in a light year radius.
| If the black hole captured the star, the tidal forces would
| slowly rip the planets apart.
| wang_li wrote:
| If the person above did their math correctly, a black hole
| and a star orbiting each other a 1.39 AU would be a problem
| for planets. Injecting a black hole like that into our
| solar system would be real trouble for Mercury, Venus,
| Earth, Mars, probably Jupiter, and Saturn too. The rest
| might be ok after a long while for their orbits to
| stabilize.
| cwillu wrote:
| Earth's orbit being disturbed fiction: A Pail of Air by Fritz
| Leiber and Perihelion Summer by Greg Egan
| fjarlq wrote:
| And the Do Not Go Gentle novels by Mark Millstorm.
| bArray wrote:
| 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.
| dfgtyu65r wrote:
| If you're interested in reading something similar, your
| description reminds me of The Black Cloud by the
| astrophysicist Fred Hoyle. I have to say I found the
| writing quite clumsy, but owing to him being an
| astrophysicist himself there was quite a lot of attention
| to detail in making the plot scientifically realistic
| (within certain bounds).
|
| https://en.wikipedia.org/wiki/The_Black_Cloud
| doctoboggan wrote:
| Perihelion Summer[0] by Greg Egan is a great story with a
| similar premise (A black hole passing by the solar system
| and affecting earth's orbit)
|
| [0]: https://amzn.to/3DNiUDj
| dkural wrote:
| I'm hooked. You should write this up as a screenplay.
| pyuser583 wrote:
| That's basically the plot of Three Body Problem.
|
| Is suspect Netflix PR is somewhere lurking around.
| jl6 wrote:
| 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.
| shagie wrote:
| 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.
| sulam wrote:
| That's how I interpret this as well.
| twawaaay wrote:
| 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 wrote:
| 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."
| [deleted]
| CalChris wrote:
| 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 wrote:
| 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.
| [deleted]
| jayess wrote:
| What is a dormant black hole?
| rsstack wrote:
| It isn't actively consuming new matter, which means it doesn't
| emit easily-visible radiation.
| codethief wrote:
| A non-active one, i.e. without a significant accretion disk.
| DoneWithAllThat wrote:
| I'm not an academic so maybe this is normal but 20+ "authors" of
| a paper seems crazy to me.
| taubek wrote:
| For some science fields it is totally normal to have so many
| people working on the same paper/project.
| gus_massa wrote:
| 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.
| TeMPOraL wrote:
| Seems to be common these days in astrophysics and particle
| physics, where you have many teams across multiple institutions
| collaborating on the research.
| zh217 wrote:
| 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 wrote:
| 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.
| deathanatos wrote:
| My SO humorously proposes "Dyson Sphere" as the explanation for
| the dark companion mass.
| dpeck wrote:
| Nearly everyone who was a teenager in the 1990s had the same song
| lyric play in their head When reading this headline.
| Maursault wrote:
| This one?[0]
|
| [0] https://www.youtube.com/watch?v=VgGBB0hTqo0
| lostgame wrote:
| You have made my day. This is amazing.
| [deleted]
| ISL wrote:
| That's incredible.
| mynegation wrote:
| Ooh, well played! Not GP, but - yes - this one.
| tantalor wrote:
| https://en.m.wikipedia.org/wiki/Lounge-A-Palooza
| rtanks wrote:
| And some adults
| BurningFrog wrote:
| This was the second most played song on the radio when I drove
| to Idaho for the 2017 eclipse.
| phoe-krk wrote:
| 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
| karmakaze wrote:
| 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.
| ISL wrote:
| 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.
| sulam wrote:
| 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 wrote:
| 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...
| Tepix wrote:
| The paper is not yet on sci-hub.
|
| arXiv link: https://arxiv.org/abs/2209.06833
| soraki_soladead wrote:
| 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?
| Tepix wrote:
| 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.
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