Page 2 of 6 FirstFirst 1234 ... LastLast
Results 31 to 60 of 174

Thread: Betelgeuse Fainting

  1. #31
    Join Date
    Jun 2005
    Posts
    14,436
    Quote Originally Posted by Strange View Post
    And doesn't the NDE at the end stand for Neutrino Detector Experiment (or something) based at Kamioka?
    Yes, and just to add one other interesting tidbit, its a very cute name in Japanese because it is a homonym for the phrase 神を噛んで, which means to bite God.


    Sent from my iPhone using Tapatalk
    As above, so below

  2. #32
    Join Date
    Mar 2007
    Location
    Falls Church, VA (near Washington, DC)
    Posts
    9,032
    Check out this AAVSO chart going back to 1911.
    https://www.aavso.org/sites/default/...betelgeuse.jpg
    There are a few faintings of similar magnitude if we look back far enough. If the AASVO observers are right, it would appear that some of the reports linked here are mistaken if they say this is the faintest it has ever been.

  3. #33
    Join Date
    Jul 2005
    Location
    Massachusetts, USA
    Posts
    22,123
    Quote Originally Posted by Hornblower View Post
    Check out this AAVSO chart going back to 1911.
    https://www.aavso.org/sites/default/...betelgeuse.jpg
    There are a few faintings of similar magnitude if we look back far enough. If the AASVO observers are right, it would appear that some of the reports linked here are mistaken if they say this is the faintest it has ever been.
    Looks like it got about this dim in 1947 (or so), and then went on to be nearly as bright as it ever gets for several months.
    Forming opinions as we speak

  4. #34
    Join Date
    Sep 2003
    Posts
    13,162
    Quote Originally Posted by Superluminal View Post
    http://www.astronomerstelegram.org/?read=13410
    Get out the smelling salts. Betelgeuse is still feeling faint.
    Their claim that a 100K temp. drop and a 9% radial increase will produce their claim for the 75% bol. luminosity change is obviously flawed.

    It appears they swapped numerator for denominator in their radius change equation. Correcting for this shows a 16% reduction in radius.

    As they note, however, the "fainting episode" may be due [in part] to expelled gas. [Hmmm, nope I won't do it!]

    Wouldn't the line data reveal the extent of the extinctions?
    We know time flies, we just can't see its wings.

  5. #35
    Join Date
    Oct 2001
    Location
    The Space Coast
    Posts
    4,678
    For any Tweeps out there, there's a bot account called Betelgeuse Status (@betelbot) that posts +/- daily plots based on previous days' observations of Betelgeuse's magnitude.

    https://twitter.com/betelbot

    CJSF
    Last edited by CJSF; 2020-Jan-28 at 05:57 PM. Reason: weird wording
    "The sun is a quagmire
    It's not made of fire
    Forget what you've been told in the past
    Electrons are free
    (Plasma!) Fourth state of matter
    Not gas, not liquid, not solid"

    -They Might Be Giants, "Why Does The Sun Really Shine?"


    lonelybirder.org

  6. #36
    Join Date
    Sep 2003
    Posts
    13,162
    Quote Originally Posted by George View Post
    Their claim that a 100K temp. drop and a 9% radial increase will produce their claim for the 75% bol. luminosity change is obviously flawed.

    It appears they swapped numerator for denominator in their radius change equation. Correcting for this shows a 16% reduction in radius.

    As they note, however, the "fainting episode" may be due [in part] to expelled gas. [Hmmm, nope I won't do it!]

    Wouldn't the line data reveal the extent of the extinctions?
    Correction: I failed to square the result. Although some or all faintness could be due to expelled gas, if not, the change in radius would be ~ 30%!
    We know time flies, we just can't see its wings.

  7. #37
    Join Date
    Sep 2003
    Posts
    13,162
    Quote Originally Posted by George View Post
    Correction: I failed to square the result. Although some or all faintness could be due to expelled gas, if not, the change in radius would be ~ 30%!
    Assuming my math is correct and the data from the prior link is correct, is anyone currently imaging Betelgeuse to see just how much it has shrunk from prior images? That would help reveal the extent of the out-gassing, right?
    We know time flies, we just can't see its wings.

  8. #38
    Join Date
    Oct 2001
    Location
    The Space Coast
    Posts
    4,678
    Some (very) preliminary observational evidence that the "fainting" may be ending.

    https://twitter.com/chmn_victor/stat...50793121153024

    Minimum mag seems to have been 1.64, in line with at least some predictions, a day or two ago. Sure, it's only one or two data points, but if you read the thread and see the plots, it's compelling. But we'll have to wait some more time to verify any trend.

    CJSF
    "The sun is a quagmire
    It's not made of fire
    Forget what you've been told in the past
    Electrons are free
    (Plasma!) Fourth state of matter
    Not gas, not liquid, not solid"

    -They Might Be Giants, "Why Does The Sun Really Shine?"


    lonelybirder.org

  9. #39
    Join Date
    Jul 2005
    Location
    Massachusetts, USA
    Posts
    22,123
    I went to the AAVSO site (aavso.org) and selected Plot A Light Curve from the menu on the far right, and looked at Betelgeuse for the last year or so. It breaks down the estimates into several bands. There seems to be the least uncertainty in the blue band, which seems to show that the fainting may be slowing, but it will probably get a little fainter before it starts getting brighter again (The UV band seems to agree, but there is less data there). The writers in the twitter feed CJSF points to were relying on statistically small sampling. In any case this looks like a good place to go for daily updates on Betelgeuse.
    Forming opinions as we speak

  10. #40
    Join Date
    Sep 2003
    Posts
    13,162
    Quote Originally Posted by CJSF View Post
    Some (very) preliminary observational evidence that the "fainting" may be ending.

    https://twitter.com/chmn_victor/stat...50793121153024

    Minimum mag seems to have been 1.64, in line with at least some predictions, a day or two ago.
    It's amazing to look up at Orion and see Betelgeuse struggling to beat Bellatrix, now matched at 1.64 mag., as well as stay ahead of the belt stars (eg Alnilam at 1.69).

    If in Galileo's time, he might have added Betelgeuse to his list of observable arguments opposing the peripatetic (Aristotelian) philosophers.
    We know time flies, we just can't see its wings.

  11. #41
    Join Date
    Jun 2004
    Location
    The Great NorthWet
    Posts
    15,970
    It's winter in the Pacific Northwest. I'd be amazed to be able to look up at Orion at all.
    Cum catapultae proscriptae erunt tum soli proscript catapultas habebunt.

  12. #42
    Join Date
    Sep 2003
    Posts
    13,162
    Quote Originally Posted by Trebuchet View Post
    It's winter in the Pacific Northwest. I'd be amazed to be able to look up at Orion at all.
    I attempted to save you the trouble, but the cloud bank was moving too quick for me to get on a tripod, though the streaking produces better color, I suppose.

    Fainting Betelgeuse.jpg
    We know time flies, we just can't see its wings.

  13. #43
    Join Date
    Oct 2001
    Location
    The Space Coast
    Posts
    4,678
    It's still brightening, about 1% of it's average/usual brigthness per day over the past several days. I'm not sure exactly how that's calculated, it being a variable star... Here's the latest graph in that regard.

    https://twitter.com/betelbot/status/1223321097745174531

    CJSF
    "The sun is a quagmire
    It's not made of fire
    Forget what you've been told in the past
    Electrons are free
    (Plasma!) Fourth state of matter
    Not gas, not liquid, not solid"

    -They Might Be Giants, "Why Does The Sun Really Shine?"


    lonelybirder.org

  14. #44
    Join Date
    Feb 2005
    Posts
    11,950
    I have heard that this star may have eaten a companion:
    https://www.space.com/35084-betelgeu...-cannibal.html

    Now this is far fetched--but could the variability be from one star orbiting within the envelope of the other?

  15. #45
    Join Date
    Jul 2005
    Location
    Massachusetts, USA
    Posts
    22,123
    Today, it looks like it is brightening (within the error bars of small sample statistics) in the red wavelengths, but still dimming slightly in the blue.
    Forming opinions as we speak

  16. #46
    Join Date
    Aug 2003
    Posts
    2,023
    After my own observations last night with a C-8 Schimt-Cass, Betelgeuse seemed to be equal to +1.6 Bellatrix. And looking at AAVSO for the first couple of days of February, still seems to be creeping down slowly.
    https://www.aavso.org/apps/webobs/re...um_results=200

  17. #47
    Join Date
    Jul 2005
    Location
    Massachusetts, USA
    Posts
    22,123
    Quote Originally Posted by Superluminal View Post
    After my own observations last night with a C-8 Schimt-Cass, Betelgeuse seemed to be equal to +1.6 Bellatrix. And looking at AAVSO for the first couple of days of February, still seems to be creeping down slowly.
    https://www.aavso.org/apps/webobs/re...um_results=200
    I admire you for going out and trying to compare it to Bellatrix, and perhaps the belt stars. I used the AAVSO build a light curve tool. It is reporting fewer extremely low brightnesses in the red, making the red average go up. Over all, the brightness has been around 1.65 to 1.60 for ten days or so. That may or may not be long enough to claim a trend.
    Forming opinions as we speak

  18. #48
    Join Date
    Aug 2003
    Posts
    2,023
    I've noticed on AAVSO, that visual observer's tend to be a little all over the place. Mags from +1.3 to +1.7. But today most reports were below +1.5. Next couple of weeks should be interesting.

  19. #49
    Join Date
    Sep 2003
    Posts
    13,162
    Quote Originally Posted by antoniseb View Post
    I admire you for going out and trying to compare it to Bellatrix, and perhaps the belt stars. I used the AAVSO build a light curve tool. It is reporting fewer extremely low brightnesses in the red, making the red average go up.
    So does that suggest an ejected cloud is expanding enough to allow more light through but favoring red due to less scattering? Or is the translucent envelope heating-up, or both?
    We know time flies, we just can't see its wings.

  20. #50
    Join Date
    Jul 2005
    Location
    Massachusetts, USA
    Posts
    22,123
    Quote Originally Posted by George View Post
    So does that suggest an ejected cloud is expanding enough to allow more light through but favoring red due to less scattering? Or is the translucent envelope heating-up, or both?
    I don't want to sound like I have a strongly informed opinion about this because I don't. Here's my weakly informed opinion: Yes, the light we see coming from Betelgeuse is the light escaping from its very wide (geometrically) thin (density) photosphere, as filtered by whatever dust and gas layer it has emitted relatively recently. I haven't personally seen anything about the changing fine spectral details, only the various magnitudes of the pass bands. That being said, I think a model using dust extinction might explain it, but I think more likely, an expansion of the photosphere and associated drop in temperature associated with the ideal gas law might also explain this. A close look at the spectrum might tell more, but I don't know enough to interpret even if I saw the spectra. I'd also like to see some interferometric images to see how the size and shape have changed during this event. Let's hope for a paper on the topic!
    Forming opinions as we speak

  21. #51
    Join Date
    Sep 2003
    Posts
    13,162
    Quote Originally Posted by antoniseb View Post
    I don't want to sound like I have a strongly informed opinion about this because I don't. Here's my weakly informed opinion: Yes, the light we see coming from Betelgeuse is the light escaping from its very wide (geometrically) thin (density) photosphere, as filtered by whatever dust and gas layer it has emitted relatively recently. I haven't personally seen anything about the changing fine spectral details, only the various magnitudes of the pass bands. That being said, I think a model using dust extinction might explain it, but I think more likely, an expansion of the photosphere and associated drop in temperature associated with the ideal gas law might also explain this. A close look at the spectrum might tell more, but I don't know enough to interpret even if I saw the spectra. I'd also like to see some interferometric images to see how the size and shape have changed during this event. Let's hope for a paper on the topic!
    Thanks for that review. I assume there is enough disk imaging history to show radial size variations, but no doubt now is the time to get a new one.
    We know time flies, we just can't see its wings.

  22. #52
    Join Date
    Aug 2003
    Posts
    2,023
    Seems they're expecting the fainting to stop February 20th, +- 7 days.
    http://www.astronomerstelegram.org/?read=13439

  23. #53
    Join Date
    Jul 2005
    Location
    Massachusetts, USA
    Posts
    22,123
    Quote Originally Posted by Superluminal View Post
    Seems they're expecting the fainting to stop February 20th, +- 7 days.
    http://www.astronomerstelegram.org/?read=13439
    Thanks! I don't expect the next few days to provide important clues since Moonlight will be making the magnitude judgements more difficult.
    Forming opinions as we speak

  24. #54
    Join Date
    Jul 2005
    Location
    Massachusetts, USA
    Posts
    22,123
    Probably not statistically important, but the blue magnitude ticked up a small fraction for the first time since careful measurement of the fainting began. This happened a few hours after a low outlier visual magnitude of 2.0 was reported for the first time.
    Forming opinions as we speak

  25. #55
    Join Date
    Oct 2001
    Location
    The Space Coast
    Posts
    4,678
    The Betelbot reports via Miguel Montarges that the European Southern Observatory's Very Large Telescope observed and will take measurements of Betelgeuse's diameter using adaptive optics and IR interferometry to see if there's been any significant change.

    https://twitter.com/Astro_MiguelM/st...26557017673728

    CJSF
    "The sun is a quagmire
    It's not made of fire
    Forget what you've been told in the past
    Electrons are free
    (Plasma!) Fourth state of matter
    Not gas, not liquid, not solid"

    -They Might Be Giants, "Why Does The Sun Really Shine?"


    lonelybirder.org

  26. #56
    Join Date
    Sep 2003
    Posts
    13,162
    Quote Originally Posted by CJSF View Post
    The Betelbot reports via Miguel Montarges that the European Southern Observatory's Very Large Telescope observed and will take measurements of Betelgeuse's diameter using adaptive optics and IR interferometry to see if there's been any significant change.

    https://twitter.com/Astro_MiguelM/st...26557017673728

    CJSF
    Nice! An animated gif, similar to the V838 Mon video would be great.
    We know time flies, we just can't see its wings.

  27. #57
    Join Date
    Oct 2001
    Location
    The Space Coast
    Posts
    4,678
    I saw earlier that the visible % estimate was down to 34 today... I know it's still not truly "unprecedented" but it would be "fun" if the models are wrong and this continued slow decline does surprise us with a bang!

    CJSF

    P.S.
    I know... not likely...
    "The sun is a quagmire
    It's not made of fire
    Forget what you've been told in the past
    Electrons are free
    (Plasma!) Fourth state of matter
    Not gas, not liquid, not solid"

    -They Might Be Giants, "Why Does The Sun Really Shine?"


    lonelybirder.org

  28. #58
    Join Date
    Jun 2005
    Posts
    14,436
    Quote Originally Posted by CJSF View Post

    P.S.
    I know... not likely...
    Sure, but it never hurts to wish.


    Sent from my iPhone using Tapatalk
    As above, so below

  29. #59
    Join Date
    Aug 2003
    Posts
    2,023
    I predict a major outburst in June, when Betelgeuse is behind the Sun and no one will notice.

  30. #60
    Join Date
    Jul 2005
    Location
    Massachusetts, USA
    Posts
    22,123
    Quote Originally Posted by Superluminal View Post
    I predict a major outburst in June, when Betelgeuse is behind the Sun and no one will notice.
    Maybe we could get the MSL Curiosity team to keep an eye on it
    Forming opinions as we speak

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •