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`Irony` actually does mean `metal like`...

V838 is a hugely fascinating object.

When I wrote a Wikipedia article on the star, it became clear that astronomers have still not found any consensus for the origin of the eruption, let alone the type of the star. It may either be a recently born or dying star or an erupting supergiant. More interesting possibilities are merging stars or (less likely) a star which has engulfed its planets.

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Science is a way of trying not to fool yourself. The first principle is that you must not fool yourself, and you are the easiest person to fool.
-- Richard Feynman

Nice article, Kullat Nunu. It appears this new article has some impact on some of the scenarios. The massive star model seems liess likely.

I am intrigued with the planetary capture model, due to migrations. If planets spiraling into their host are more common than we might expect, would we notice the resulting flash very often? We seem fortunate that an envelope happens to be arround this star, revealing the flash due to the echo. This article suggests the envelope is not from the flashing star itself, thus it is less likely we wold notice flashing stars which have no envelope.

Is there any light curve for these flashes from V838 Mon?

Bill Keel's (ngc3314) latest book shows that the echo we see is in an ellipsoidal reflection, which I thought was interesting for some reason. I'm not sure why it impressed me; perhaps it justifys learning about ellipises.

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Lighten up! This is a stellar board! Author: duh.

"The Sun, with all the planets revolving around it, and depending on it, can still ripen a bunch of grapes as though it had nothing else in the universe to do..." Author: Galileo supposedly.

The preprint of the Nature article has a light curve which shows the change of brightness in three wavelengths.

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Science is a way of trying not to fool yourself. The first principle is that you must not fool yourself, and you are the easiest person to fool.
-- Richard Feynman

Thanks. Great paper because it is such a fantastic object to see.

As usual, I am a little puzzled with some of it. I would have guessed with a propogation rate of c, that simple trig would give us distance. Of course, there would be some question due to the parabolid (I may have been wrong in saying Bill said ellipsoidal) reflection pattern. It appears they are able to use polarization to refine the location of the reflection. This yields a minimum of 6kpc, though they mentioned earlier in the paper a minimum of 2kpc from another technique.

The 6kpc minimum demonstrates by direct measurement, once again as in sn1987a, that the universe is > 6000 lyr. radius. Aren't you glad to know that.

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Lighten up! This is a stellar board! Author: duh.

"The Sun, with all the planets revolving around it, and depending on it, can still ripen a bunch of grapes as though it had nothing else in the universe to do..." Author: Galileo supposedly.