[HN Gopher] A star system 3,000 light-years away is predicted to...
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A star system 3,000 light-years away is predicted to become visible
soon
Author : gnabgib
Score : 174 points
Date : 2024-03-19 01:40 UTC (21 hours ago)
(HTM) web link (blogs.nasa.gov)
(TXT) w3m dump (blogs.nasa.gov)
| dredmorbius wrote:
| Nasa's report, which BI cites (and blocks the link behind a
| regwall) is here:
|
| "View Nova Explosion, 'New' Star in Northern Crown"
|
| <https://blogs.nasa.gov/Watch_the_Skies/2024/02/27/view-nova-...>
|
| This also adds the useful information that this is a _recurring_
| nova, though I 'd like to know how the forecast is being made and
| what it's based on.
| mr_toad wrote:
| Just past observations. If you've seen it go nova exactly every
| 80 years odds are it will do it again. Some nova are very
| regular, others can be unpredictable.
| dredmorbius wrote:
| That makes sense. As opposed to a main-sequence nova, in
| which a very-late-sequence star goes through the _advanced
| burning_ phases, with fusion progressively of carbon, neon,
| oxygen, and finally silicon (to iron) occurs. The final
| stages of this occur quite quickly, on the order of months,
| weeks, days, and even hours, as I understand. Whether or not
| the burning phases can be astronomically observed and
| predicted I don 't know, and was what inspired my question
| above.
|
| <https://ned.ipac.caltech.edu/level5/Sept16/Rauscher/Rauscher
| ...>
|
| For a 25M star (one 25 times our Sun's mass), these phases
| last ~0.5 my (helium), ~600 years (carbon), 6 months (neon),
| 6 days (oxygen), and about a day (silicon).
|
| (More massive stars burn much hotter and faster than lighter
| ones.)
| dang wrote:
| Ok, we'll change to that from
| https://www.businessinsider.com/how-to-see-exploding-star-no...
| above. Thanks!
| PopePompus wrote:
| From the article: "As the red giant tears apart nearby stars, the
| dense white giant absorbs the shrapnel, a mixture of hydrogen-
| rich materials that come its way. The tiny dead star then
| gradually becomes hotter until it reaches a breaking point when
| all that energy is released in a huge cosmic explosion -- a so-
| called nova."
|
| That's the worst explanation of a nova I've ever seen. You'd
| think the author would have at least glanced at the Wikipedia
| article about novae.
| febed wrote:
| The explanation isn't good but they aren't talking about a
| normal supernova here, it's a recurring one that I too never
| heard about earlier.
| gus_massa wrote:
| Nitpicking: Don't confuse https://en.wikipedia.org/wiki/Nova
| and https://en.wikipedia.org/wiki/Supernova
|
| From Wikipedia:
|
| > _For other uses, see Nova (disambiguation), Novas
| (disambiguation), and Novae (disambiguation)._
|
| > _Not to be confused with luminous red nova, supernova,
| kilonova, or micronova._
|
| (Disclaimer: I have no idea what half of them mean, but I
| guess they are nasty things that can make a star brighter.)
| JumpCrisscross wrote:
| Yup, syndrome versus disease.
| dredmorbius wrote:
| NB: The quoted text appears in the BI article originally
| submitted.
|
| <https://www.businessinsider.com/how-to-see-exploding-star-
| no...>
|
| The URL's been changed to the Nasa source it references.
| ahazred8ta wrote:
| T Coronae Borealis is overhead in the evening in July. It's
| expected to go nova in 2024 brightening from mag10 to mag3.
| https://en.wikipedia.org/wiki/T_Coronae_Borealis
| denton-scratch wrote:
| > T Coronae Borealis is overhead in the evening in July.
|
| Sort of depends on where your head is located.
| irrational wrote:
| It's unfortunate that where I live, it doesn't get dark until
| well after bedtime in July.
| ars wrote:
| The reason is predictable is that it repeats every 80 years or so
| - I guess that's the orbit of the dwarf sun it's eating.
| mr_toad wrote:
| The orbital period is 228 days. They are very close (relative
| to the size of the red giant) which is why the white dwarf is
| absorbing material from the other star.
|
| https://en.wikipedia.org/wiki/T_Coronae_Borealis
| Fezzik wrote:
| The NYT posted the (better) article that BI cribbed from 10 days
| ago: https://www.nytimes.com/article/nova-new-star-t-coronae-
| bore...
| mysterypie wrote:
| It's nice that the nuclear explosion of novas and supernovas
| occur on a human perceptible timescale -- taking weeks to months,
| instead of a nanosecond or ten million years. I'm not suggesting
| anything superstitious or supernatural about it. Just that it's
| oddly convenient.
| teraflop wrote:
| The speed of light pretty much precludes anything happening to
| an entire star on a nanosecond timescale.
|
| In the other direction, it's basically a tautology. A "nova" or
| "new star" is, _by definition_ , a relatively fast change. Much
| slower changes to stars also occur, but they tend not to get
| news articles written about them when they happen gradually
| over millions of years, and we don't call them novas.
| dredmorbius wrote:
| For a main-sequence star, yes.
|
| For a neutron star, at ~12 -- 30 km diameter, light-speed
| timescales are on the order of 40--100 microseconds, which
| would be the _lower_ bound on whole-star cataclysmic events.
|
| (Time dilation might extend this somewhat, perhaps by a
| factor of two or so.)
|
| For a white dwarf, ~10,000 km, lightspeed events would be
| about 30 milliseconds (~300 times longer than on the neutron
| star). That's about 1/10 of an eyeblink.
| teekert wrote:
| I'm not religious but my fav "that's oddly convenient" fact is
| that just by going fast enough you can cross the universe in a
| human lifetime because of time slowing down. As a biologist I
| find that much more fascinating than all those poor
| "irreducible complexity" anti-evolution arguments. Perhaps a
| physicist feels the other way around.
| Arnavion wrote:
| Well, you can cross the universe in any amount of time. The
| human lifetime isn't special in that regard. A photon crosses
| the universe in zero time, and anything with non-zero mass
| can get arbitrarily close to zero time.
| dredmorbius wrote:
| As I've seen this point made in the past, it's that
| _travelling at a constant 1g acceleration_ the subjective
| time for an astronaut would be about 45 years in traversing
| the observable Universe (~14 billion light years).
|
| That is, a comfortable and familiar acceleration gives a
| human-lifetime-equivalent journey (subjective time).
|
| If you're planning a round-trip, you'll find rather more
| time has transpired on what used to be Earth.
|
| <https://www.universetoday.com/129086/far-can-travel/>
| saalweachter wrote:
| > If you're planning a round-trip, you'll find rather
| more time has transpired on what used to be Earth.
|
| Or less, depending on the rotation of the universe as a
| whole.
| ben_w wrote:
| Or no return may be possible at any speed/acceleration
| given the expansion of the universe.
| dredmorbius wrote:
| Given that the outbound journey is already technically
| challenging, that's very nearly quibbling, despite
| cosmological accuracy.
| heavenlyblue wrote:
| That 1g constant acceleration requires practically
| infinite amounts of energy
| denton-scratch wrote:
| > A photon crosses the universe in zero time
|
| That is not consistent with my observations.
| Intralexical wrote:
| Multiple universes, perhaps, depending on your
| cosmology/eschatology:
|
| https://en.wikipedia.org/wiki/Tau_Zero
| yitchelle wrote:
| Surely these are occurring very frequently as there are
| trillions of stars out there. I imagine that space is so vast
| that the vastness makes these events difficult to observe. Am I
| wrong with this thought?
| widforss wrote:
| > This recurring nova is only one of five in our galaxy.
| kugelblitz wrote:
| > This could be a once-in-a-lifetime viewing opportunity as
| the nova ouburst [sic] only occurs about every 80 years.
| SiempreViernes wrote:
| Just like how you can't see much of your body (without
| mirrors) because your body is in the way, we can't see much
| of the galaxy because there's galaxy in the way.
| NohatCoder wrote:
| It is only 2600 light years away. Our galaxy is a little
| under 100000 light years across, depending on how you
| measure. So it is a rare type of double star, and it is very
| close to Earth, the combination is what makes it special.
| sweezyjeezy wrote:
| Example: the Crab Nebula was the result of a supernova that was
| seen by Chinese astronomers about 1000 years ago:
| https://en.wikipedia.org/wiki/Crab_Nebula
| neurostimulant wrote:
| > The star system, normally magnitude +10, which is far too dim
| to see with the unaided eye, will jump to magnitude +2 during the
| event. This will be of similar brightness to the North Star,
| Polaris.
|
| I've never been in the northern hemisphere so I don't know how
| bright the polaris is :(
| lou1306 wrote:
| Not _that_ bright but it is visible to the naked eye even in
| presence of mild light pollution.
| itishappy wrote:
| I've never been to the southern hemisphere either, but
| Wikipedia's got our back!
|
| https://en.wikipedia.org/wiki/List_of_brightest_stars
|
| Looks like similarly bright southern stars include some of the
| following:
|
| https://en.wikipedia.org/wiki/Alphard
|
| https://en.wikipedia.org/wiki/Beta_Ceti
|
| https://en.wikipedia.org/wiki/Alpha_Pavonis
|
| https://en.wikipedia.org/wiki/Alpha_Trianguli_Australis
|
| It's pretty bright, but not uniquely so. It'd be about the 20th
| brightest object in the sky (assuming even distribution).
| denton-scratch wrote:
| It's visible with the naked eye, even in the presence of light
| pollution. But it's not eye-catching.
| baggy_trough wrote:
| Corona Borealis is easy to see from the northern hemisphere. This
| nova gets to around 2.5 magnitude which should make it fair game
| to pick out with the eye even with some light pollution as in the
| SF bay area.
| bkloppenborg wrote:
| In case anyone is interested in learning more about this star,
| Dr. Brad Schaefer wrote a nice article about it in the March 2024
| issue of Sky and Telescope (subscription required):
|
| https://skyandtelescope.org/sky-and-telescope-magazine/insid...
|
| There is also an open-access journal article from March 2023 that
| summarizes his research on the system:
|
| https://academic.oup.com/mnras/article/524/2/3146/7077557.
|
| And a blog post announcing the latest estimate for the eruption
| (2024.4 +/- 0.4):
|
| https://www.aavso.org/news/t-crb-pre-eruption-dip
|
| My organization, the AAVSO, has material that can help you learn
| how to observe variable stars and make scientifically useful
| measurements. You can do this by eye, with binoculars, with a
| telescope, or with various digital sensors. In the case of T CrB,
| visual observations will yield very useful information. Please
| see https://www.aavso.org/tutorials and
| https://www.aavso.org/observing-manuals for more information.
| punyearthling wrote:
| business insider is maliciously unhelpful
| mateo1 wrote:
| Is there a mailing list or something that I can register to in
| case that actually happens? I bet Ill miss the news.
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(page generated 2024-03-19 23:02 UTC)