V is For Valentine… V838


And the V we’re taking a stereo look at on Valentine’s Day is V838 Monocerotis – an unusual “light echo” from a variable star. If you’re curious to know more about what you’re looking at, then prepare to take a 20,000 light year journey across space and step inside…

Like all our our “stereo” image produced for UT by Jukka Metsavainio, two versions are presented here. The one above is parallel vision – where you relax your eyes and when you are a certain distance from the monitor screen the two images will merge into one to produce a 3D version. The second – which appears below – is crossed vision. This is for those who have better success crossing their eyes to form a third, central image where the dimensional effect occurs. Jukka’s visualizations of what Hubble images would look like if we were able to see them in dimension come from studying the object, its known field star distances and the different wavelengths of light. Are you ready to “cross” the boundary? Then let’s rock…

V838 Monocerotis Cross-Vision by Jukka Metsavainio
V838 Monocerotis Cross-Vision by Jukka Metsavainio

When you’re ready to come back to your seat, let’s talk just a little bit about what V838 Monocerotis is and what we currently know about it.

The primary source of light that you’re seeing in here comes from a variable star – the 838th variable star discovered in the constellation of Monocerotis – which underwent a very strange reaction early in 2002. At first astronomers believed it to be a pretty normal nova event, but it didn’t take long to realize this was something altogether different than anything they’d ever witnessed.

When it first began to brighten on January 10, 2002, the light curve measurements began. These graphs show the intensity of light as a function of time – and they came back as ordinary… a white dwarf shedding accumulated hydrogen gas from its binary neighbor. By February 6th, it had reached its maximum visual brightness and started to dim again, just as expected – but only weeks later the infrared wavelength began to do some very strange things – it brightened unexpectedly and did it again just a few more weeks later! This was something astronomers had simply never witnessed…

According to Howard Bond; “Some classes of stars, including novae and supernovae, undergo explosive outbursts that eject stellar material into space. In 2002, the previously unknown variable star V838 Monocerotis brightened suddenly by a factor of ~104. Unlike a supernova or nova, it did not explosively eject its outer layers; rather, it simply expanded to become a cool supergiant with a moderate-velocity stellar wind. Superluminal light echoes were discovered as light from the outburst propagated into the surrounding, pre-existing circumstellar dust. At its maximum brightness (it) was temporarily the brightest star in the Milky Way. The presence of the circumstellar dust implies that previous eruptions have occurred, and spectra show it to be a binary system. When combined with the high luminosity and unusual outburst behaviour, these characteristics indicate that V838 Mon represents a hitherto unknown type of stellar outburst, for which we have no completely satisfactory physical explanation.”

At the time, V838 expanded in size to the point where it would have filled our solar system to the size of Jupiter’s orbit and output a million times the luminosity of our own Sun – changes that happened in an abnormal time span of just months. Since science did have pre-eruption photographs, V838 was thought to be an under luminous F-type dwarf – much like Sol – which deepened the mystery even further. Just what could cause it to go against the laws of thermodynamics?

According to R. Tylenda; “The eruption phase, which lasted till mid-April 2002, resulted from a very strong energy burst, which presumably took place in last days of January at the base of the stellar envelope inflated in pre-eruption. The burst produced an energy wave, which was observed as a strong luminosity flash in the beginning of February, followed by a strong mass outflow in form of two shells, which was observed as an expanding photosphere in later epochs. In mid-April, when the outflow became optically transparent and most of its energy radiated away, the object entered the decline phase during which V838 Mon was evolving along the Hayashi track. This we interpret as an evidence that the main energy source during decline was due to gravitational contraction of the object envelope inflated in eruption. Late in 2002 a dust formation started in the expanding shells which gave rise to a strong infrared excess observed in 2003.”

Since then we’ve learned the V838 eruptive star may have just been entering the main sequence at the time, and we also know it has a B-type companion that’s also just come aboard the main sequence train. This type of information doesn’t add up to a nova event which occurs to older, white dwarfs… even though it may be something we don’t yet understand. It’s possible that V838 Monocerotis may be a post-asymptotic giant branch star – about to end – but again, it doesn’t fit the spectral patterns. According to some evidence, V838 Monocerotis may be a very massive supergiant that experience “carbon flash”… making their way towards the Wolf-Rayet star end of the chapter. It’s possible that the event could have been a “mergeburst” – where a main sequence and pre-main sequence star combined forces – or even a planetary captured event which triggered deuterium fusion.

And maybe we’ll never know in our lifetimes…

No matter if we understand precisely what created it or not, we can still enjoy the wonderful “light echo” produced by V838 Monocerotis, imaged by the Hubble Telescope and visualized for dimension by Jukka. He understands how the light reflects from clouds of interstellar matter between the star and point of the observer. He knows which wavelengths arrived into the camera lens first and which arrived last…

And we’re grateful to have the chance to look straight into the “heart” of this unusual phenomena!

My many thanks once again to Jukka Metsavainio of Northern Galactic for his artistry and we look forward to the next installment!

16 Replies to “V is For Valentine… V838”

  1. Wow! Tammy! That’s incredible! Never fully appreciated V838 until now – that effect really highlights it’s 3D structure. I’m going to have to post this on Astroengine!

    Cheers, Ian

  2. Beautiful as the are…. don’t imagine the stereo effects replicate what you would actually – or for that matter what hubble would see

    Your eyes would need to be a light year or so apart (at this distance) to get a stereoscopic image – and even then the sense of depth would be virtually non existant because the near and far side of this object are (by proportion and for all practical purposes) the distance away from us.

  3. Beautiful – it’s my second most favourite image in this series of “stereoscopic” pictures. Thanks to all involved for sharing!

    I have a problem with my knowledge of Physics and Mathematics, though. When you say “light echo”, I assume it means the scattering or diffusion of the light from the burst off the surrounding gas and debris. I cannot figure out how this can become superluminal.
    The only _apparently_ superluminal light I know of and can relate to is a scattering off a pair of narrow beams in opposite directions, almost (but not quite) along the line of sight of an observer. This beauty doesn’t look like what I’d imagine a tight beam effect looks like, though….. ah, well, it’s a beauty, anyway….

  4. Feenixx, I think that the radiation of the star in contraction lit up the surrounding gas, as happens in a fluorescent lamp

  5. Great image, but I’m afraid Jukka got the physics wrong here!
    If I understand the light echo stuff right, what we see is the envelope of a growing, virtual ellipsoid, the foci of which are, V838 for one, and us for the other.
    The sum of the distances between V838 and the ‘shell’, and between the shell and us, is equal for all the lit points of the shell, at any time. Just like you can draw an ellipse tightly following a rope fastened on two stakes (see the Wikipedia Ellipse article).
    That sum of distances increases over time, of course, so the ellipsoid inflates.
    The ‘outermost shells’ that we see are actually the nearest (from us) shell sections (in fact ‘rings’), and nearer from us than V838, just to satisfy that constant sum condition.
    The ‘innermost’ shells are the farthest (from us), and actually behind V838.
    It’s important to understand that we do not see any complete, spherical shell here. (We also don’t see the actual expansion of the shells, but that’s the easy part which everyone understands!)
    In Jukka’s image, the shell’s 3D is right when you look at the wrong pair: it looks like a hollow bowl turned towards us, not like a sphere!

  6. could someone please explain to me how these work? ive seen a few of these and dont understand what im meant to do with them.

  7. manu? i don’t understand what you’re seeing… but the brighter edges of the nebula seem closer to me – like i’m looking inside a christmas ornament.

    can this be a difference in how browsers work? because i use opera.

    lawmc… there’s two because people have success one of two ways. either open the full size image or use what’s here. the first, you use “averted vision” and when your eyes are level with the center of the images and a certain point away, they will appear to merge and become 3D. the second is similiar – only you cross your eyes. when you do, a third image will appear between the two… just relax and let your mind focus on the third image and the 3D will come to you.

    i’ve noticed it’s like the “magic eye” puzzles. the more i practice, the easier it becomes each time to see it. (and i tend to have the fastest success with the smaller, cross vision image.)

  8. @ Tammy:
    Thanks for answering!
    In the first image, for parallel vision, what I see (and you too, I guess: browsers can’t change that, can they?) is a background of many faint stars, a foreground of the brightest stars with I suppose V838 as the reddish one in the middle, and the ‘shell’ as an almost closed sphere (although open in the front, where it is dark and red). That ‘arm’ in the lower left corner is hanging towards the back. This looks good, but unrealistic.
    Now if I look at it cross-eyed, everything is inverted and wrong, except that the shell appears as it should: the lower left arm (and all the outer ring of the shell) has moved to the foreground, the central parts have moved back. That is, I suppose, how the shell actually looks like in the real sky, to observers in our direction: we are looking at an ellipsoid end from the inside, from the other focus!

  9. suppose we should turn the monitor around? giggle!!


    if i start thinking about it too much, i get dizzy feeling… you would think as often as i have looked at this that i wouldn’t feel anything – but i get sucked right into the image every time. even if it’s only a “viewmaster” like effect and not 100% perfect – it still fascinates me to no end. i would imagine that part of the reason is that the hubble images weren’t done with jukka’s techniques in mind and that he has to do the best he can with what he has to work with. (and the hubble images were at our request.)

    follow the link to his pages and take a look at his speciality images where he does his own photography aimed with his technique to be applied. these will blow your mind… (but let’s keep him our secret for awhile longer, eh? about the time those scientists get a hold on him, we’ll never get to share!)

  10. Look, I just carried downstairs (3 flights) my old (4 yrs) heavy (>20kg?) 19′ CRT to be picked for garbage: I’m not flying around any other monitor tonight!

  11. hey! bring that back up here!! i resemble that remark!!

    it’s an old sony trinitron multiscan 200ES… and i’m not giving it up until it gives up on me!


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