I have a bit of time on my hands, so let's do another 24h round of #AskAnAstrophysicist, but this time it's a thematic one.
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What the heck are the Little Red Dots seen by the James Webb telescope? The February SciAm said they might be "a totally new class of cosmic object". Still True?
@lemgandi it's not a question about stars - but yes, we are still not sure. People have several ideas - I'm not following closely enough to have a strong opinion on which idea is a correct one. But it's always cool and exciting when the universe sends something new our way.
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@coleenwalter it's a very cool question actually! The stars move relative to the solar system and the solar system itself moves through our galaxy, so overall the position of stars changes. The timescales are very large, though, so "just" a few thousand years ago things would not look too different, possibly not even noticeable with the nakes eye. But the further in the past you go (to pre homo sapiens time), the more different it would look - same for far away future!
@vicgrinberg that’s really interesting! I like to look up at the stars when I leave work in the evening. There’s something peaceful in knowing I’m seeing the same sky as people did for thousands of years. Kind of a thread that ties everyone together.
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@CASSCFenjoyer they certainly do! Even our sun does - it's the driver of the solar cycle and solar spots.
You can find more info here https://www.esa.int/Science_Exploration/Space_Science/The_solar_cycle_a_heartbeat_of_stellar_energy
And here is a really cool recent measurement https://www.esa.int/ESA_Multimedia/Keywords/Description/Sun_magnetic_field/(result_type)/images
@vicgrinberg Thanks
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@Enema_Cowboy that's because if you look overall into the solar system we still have a small amount of heavier elements - it's just that they are a lot more concentrated in the (rocky) planets than in the Sun where most (99.8%) of the overall material in the solar system is. So overall we still have only very little of heavier elements.
@vicgrinberg That makes sense. Would heavier metals be expected in the cores of gas and ice giant planets?
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I have a bit of time on my hands, so let's do another 24h round of #AskAnAstrophysicist, but this time it's a thematic one.
What do you want to ask an astrophysicist about stars? (I am a professional astrophysicist, part of whose work concerns itself with high mass stars & their winds and I've also taught a variety of astro university courses)
Boosts welcome. I may not be able to reply to all in case of many questions.
@vicgrinberg Can something be a star and a black hole at the same time?
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I have a bit of time on my hands, so let's do another 24h round of #AskAnAstrophysicist, but this time it's a thematic one.
What do you want to ask an astrophysicist about stars? (I am a professional astrophysicist, part of whose work concerns itself with high mass stars & their winds and I've also taught a variety of astro university courses)
Boosts welcome. I may not be able to reply to all in case of many questions.
@vicgrinberg In a “stellar nursery” where do the gases and particles come from? is it all from stars that went extinct at the same time, or is it the slow aggregation of random star dust from unrelated objects?
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@celestiallavendar I feel the same! This (or a variation thereof) https://asd.gsfc.nasa.gov/archive/mwmw/mmw_images.html is still one of my favorite images ever!
@vicgrinberg@mastodon.social Wow super cool. Thanks for sharing!!
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I have a bit of time on my hands, so let's do another 24h round of #AskAnAstrophysicist, but this time it's a thematic one.
What do you want to ask an astrophysicist about stars? (I am a professional astrophysicist, part of whose work concerns itself with high mass stars & their winds and I've also taught a variety of astro university courses)
Boosts welcome. I may not be able to reply to all in case of many questions.
@vicgrinberg how can one know the size / mass of a star and their relative distances one to another, and to us.
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I have a bit of time on my hands, so let's do another 24h round of #AskAnAstrophysicist, but this time it's a thematic one.
What do you want to ask an astrophysicist about stars? (I am a professional astrophysicist, part of whose work concerns itself with high mass stars & their winds and I've also taught a variety of astro university courses)
Boosts welcome. I may not be able to reply to all in case of many questions.
@vicgrinberg Are there solar systems out there where a star has a smaller star in its orbit?
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@vicgrinberg I boosted, but I never really learned anything about stars, so I feel totally inadequate to be asking a question. But thanks for doing this.
@johnnythan @vicgrinberg Seconded - I'm the same. I don't know enough to ask a question but am fascinated by the answers. And the questions! Thank you for sharing your time and knowledge. Great thread.
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I have a bit of time on my hands, so let's do another 24h round of #AskAnAstrophysicist, but this time it's a thematic one.
What do you want to ask an astrophysicist about stars? (I am a professional astrophysicist, part of whose work concerns itself with high mass stars & their winds and I've also taught a variety of astro university courses)
Boosts welcome. I may not be able to reply to all in case of many questions.
@vicgrinberg Is there any sensible answer to the question of what's going on inside the event horizon of a black hole?
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@Nephele to me, doing science is like doing art, it's deeply human. The first humans pressed their ocher red hands onto walls of caves and it still touches me. The same way science and trying to understand the world touches something deep in the human soul. When we stop doing art and trying to understand the world (so doing science), we stop being human.
And *hugs* it's hard times...
@vicgrinberg @Nephele This
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@vicgrinberg @sianderl @ec_euclid
OK, but many thanks for your answer anyway!
Mhm, another question regarding red dwarfs (like Proxima Centauri):
Red dwarfs may sound harmless at first, but they are much more dangerous for nearby planets (and any potential life) due to intense flares and CMEs, as well as strong magnetic fields that fluctuate considerably.
Is the only reason for this that heat transfer in these stars is convective (meaning the interior is well “stirred up” and therefore rather inhomogenous ) or are there further reasons for this behaviour?
In stars like the Sun, heat transfer occurs internally via radiation and in the outer layers via convection, without things being so uncomfortable all around....
@echopapa it's the convection and the often fast rotation - both tend to tangle the magnetic fields more leading to a higher flare rate. Very close in exoplanets could also trigger flares, again via magnetic interaction https://www.skyatnightmagazine.com/space-science/exoplanets-close-cause-solar-flares
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I have a bit of time on my hands, so let's do another 24h round of #AskAnAstrophysicist, but this time it's a thematic one.
What do you want to ask an astrophysicist about stars? (I am a professional astrophysicist, part of whose work concerns itself with high mass stars & their winds and I've also taught a variety of astro university courses)
Boosts welcome. I may not be able to reply to all in case of many questions.
@vicgrinberg there's a legend about Sirius A that used to be red before being blue. Is there any way for stars, aside from aging, to "suddenly" or not-so-suddenly change color in their lifetime?
I mostly have in mind depictions from movies where a star gets eaten by star-goo and turns green; or a "supernova-weapon" turns it an otherworldly color before it, well, goes supernova.
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@vicgrinberg Can something be a star and a black hole at the same time?
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I have a bit of time on my hands, so let's do another 24h round of #AskAnAstrophysicist, but this time it's a thematic one.
What do you want to ask an astrophysicist about stars? (I am a professional astrophysicist, part of whose work concerns itself with high mass stars & their winds and I've also taught a variety of astro university courses)
Boosts welcome. I may not be able to reply to all in case of many questions.
@vicgrinberg do most stars generate energy from nuclear fusion of hydrogen (as I understand it, like our sun) and other increasingly heavy elements? Are there other sources of energy harnessed by stars?
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I have a bit of time on my hands, so let's do another 24h round of #AskAnAstrophysicist, but this time it's a thematic one.
What do you want to ask an astrophysicist about stars? (I am a professional astrophysicist, part of whose work concerns itself with high mass stars & their winds and I've also taught a variety of astro university courses)
Boosts welcome. I may not be able to reply to all in case of many questions.
@vicgrinberg upper mass limit? Eddington limit still a thing? Deneb is my spirit star (Actually Vega, but that’s not high mass)
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@vicgrinberg what would happen to your arm if you raised it while the lightspeed is 0?
@trrektor
If light speed were zero humans would not exist and not have arms.
@vicgrinberg -
@vicgrinberg That makes sense. Would heavier metals be expected in the cores of gas and ice giant planets?
@Enema_Cowboy likely yes - but it's not that simple, eg NASA's Juno found that Jupiter core is rather "fuzzy" and not just a ball of heavy elements https://science.nasa.gov/jupiter/jupiter-facts/
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I have a bit of time on my hands, so let's do another 24h round of #AskAnAstrophysicist, but this time it's a thematic one.
What do you want to ask an astrophysicist about stars? (I am a professional astrophysicist, part of whose work concerns itself with high mass stars & their winds and I've also taught a variety of astro university courses)
Boosts welcome. I may not be able to reply to all in case of many questions.
what's the biggest star system seen?
what's the biggest star system theoretically?
i was reading about Nu Scorpii the other day, a seven star system, which blew my mind
besides the stable binary star systems, are all large star systems simply young star systems bound to break up?
