Similarly, with respect to jet phenomena of any kind, one would naturally expect that a structural symmetry on both sides would reflect the activity of a single central engine: if something big blazes up at the core, one naturally expects bright knots of plasma to be ejected in BOTH jets and that they would travel outward at comparable speeds, covering the same distance in a given amount of time from the reference frame of the central engine. BUT, if the jet axis is tilted with respect to our plane of the sky, and the jets are sufficiently extensive in lenth (say, on the order of light-years or more) one jet will inevitably be closer to a given observer like us than the other is. Thus, unless we are viewing the jets almost exactly broadside, when we measure the apparently angular distance between the central engine and apparently homologous knots on either jet, we should EXPECT to find that there will be a displacement that indicates which jet is pointed toward us and therefore closer than the oppposing jet, and would naturally find that far jet appears to have a pattern of knots measurably closer to the central engine than their counterpart knots in the jet angled toward us and therefore closer to us.

This scenario is merely a consequence of elementary geometry coupled with the finite velocity of light, and it has been well documented in a wide variety of phenomena, most strikingly – and spectacularly – documented with a series of Hubble images over the course of several years, in the 2002 outburst of V838 Monocerotis which produced a light-echo which perefectly illustrated the effect of signals being delayed from reflecting material (cirumstellar dust clouds) that is farther away compared to those signals reflected by material closer to us observers. We could actually WATCH how light reflected from stuff BEHIND the star arrived much later than light reflected off of stuff closer to us along the direct line of sight. But its vital to remember that the light echo played out over several years after the SINGLE outburst occurred: a classic case of a very brief flash of an event spread out in time because of the extension of the size of an object in terms of distance (the circumstellar dust clouds that reflected the light of the brief outburst).

It doesn’t take into account any relativistic effects which may also play a dominating role (as has frequently in fact been observed with certain quasar jets and the famous jet emmanating from the core of the Virgo galaxy cluster giant elliptical galaxy M 87), which complicates the timing issue of jets aimed nearly in our direction even more.

Given all these potential issues, the case of HH 34 is nevertheless puzzling. It does not seem to follow the simple rules I’ve outlined above. For example, it is difficult to reconclie a 4.5 year delay on one jet with respect to the other when the entire jet structure might be at most 10 to 20 light-years in extent. Moreover, its hard to understand how the optically exposed jet on the right would exhibit the LAGGING, unless it was pointed drastically AWAY from our direction compared to the opposing and optically hidden jet. There’s definitely something screwy about the asymmetry that doesn’t immediately suggest an accounting. I can’t buy the ‘sound-wave’ mechanism as an explanation yet; it seems too contrived and I can’t reconcile it with the apparent coherence exhibited on both jets over most of their extended lengths. Rather, I think, as usual, the answer will probably turn out to be a far more simple one, and one that points out some currently unnoticed observational error of some kind (even though the measured displacements are real – I measured them myself). Whatever the explanation ultimately turns out to be, encountering an authentic natural mystery is always welcome and infinitely more rewarding than messing around with the fake superstitious kind, which aren’t mysteries at all.

Yeah All you need is an object with enough mass to form a “gravity well” and some matter that intends (or is just forced to) fall onto the object. Since the infall will normally not be radially, it does not hit the object but is forced into an orbit. When there is enough matter to do this it will form a disk in equatorial plane – the accretion disk, which is revolving around the central object.
In order to get rid off this rotational movement one needs friction and magnetic fields. The latter are eventually taken with the disk, since it will turn into a plasma. Due to the rotation the magnetic field will become twisted and form two narrow channels along the rotational axis of the central object – the jets.

This is the basic picture, but the details are not yet understood.

Fascinating…

Ah, ok. Anyway, so yes, I did mean far infrared, then.

Jets are a by-product of accretion. So whenever an object consumes matter it produces jets. That’s true for black holes, neutron stars, white dwarfs and young growing stars.

The blurriness of IR images should be due to the fact that resolution is inversely proportional to the wavelength. “Near” IR is that part that is close to optical (red) light (say about 1 micron) and “far” means that it is, well, far away from the optical band (10 to 100 microns or so).

FYI, there’s a more colorful (though much smaller) animation on teh Wiki page for Herbig-Haro Objects.

Incidentally, is it just me, or do most of these infrared images look a bit blurry compared to their optical counterparts? Are far infrared wavelengths long enough to limit the resolution of IR cameras? For that matter, I can’t remember which end of the IR spectrum is “far” and which is “near”.

In space, Spitzer can hear you scream.

It’s possible, even likely, that 4.5 or so billion years ago, our own Sun looked very much like HH 34 when it was a baby.

Aww… oochy-woochy coochy-coo.*

*(From Star Trek: TOS — “Friday’s Child”.)

Three questions I’m really curious about if I may ask :

1) Can someone please enlighten us all as to what spectral class this star is – or will become?Is Herbig Haro 34 a pre-main sequence star? Proto-star? T-Tauri /Fuor / nebular variable?

2) How massive is Herbig Haro 34 versus the solar mass?

3) Do we have any more precise idea of HH 34′s exact age other than “a few million” years old?

IOW, When do we need to send it a birthdy a card & how many candles on its cake!?

But a rather unappealing analogy.

* Or is that proto-star? T-Tauri / Fuor stage?