by neufer » Thu May 12, 2011 1:32 pm
bcasa wrote:
it would be interesting if in the information some discussion was made as to approximately when this occured, since it is so many light years away, and how different it might look if you could see what it looks like now.
The observed Herbig–Haro objects (from 5,000 lyrs away) no longer exist.
http://en.wikipedia.org/wiki/Herbig-Haro_object wrote:
<<Herbig–Haro objects (HH) are small patches of nebulosity associated with newly born stars, and are formed when gas ejected by young stars collides with clouds of gas and dust nearby at speeds of several hundred kilometres per second. Herbig–Haro objects are ubiquitous in star-forming regions, and several are often seen around a single star, aligned along its rotational axis.
HH objects are transient phenomena, lasting not more than a few thousand years. They can evolve visibly over quite short timescales as they move rapidly away from their parent star into the gas clouds in interstellar space (the interstellar medium or ISM). Hubble Space Telescope observations reveal complex evolution of HH objects over a few years, as parts of them fade while others brighten as they collide with clumpy material in the interstellar medium.
Spectroscopic observations of HH objects show they are moving away from the source stars at speeds of 100 to 1000 km/s. In recent years, the high optical resolution of Hubble Space Telescope observations has revealed the proper motion of many HH objects in observations spaced several years apart. These observations have also allowed estimates of the distances of some HH objects via the expansion parallax method.
As they move away from the parent star, HH objects evolve significantly, varying in brightness on timescales of a few years. Individual knots within an object may brighten and fade or disappear entirely, while new knots have been seen to appear. As well as changes caused by interactions with the ISM, interactions between jets moving at different speeds within HH objects also cause variations.
The eruption of jets from the parent stars occurs in pulses rather than as a steady stream. The pulses may produce jets of gas moving in the same direction but at different speeds, and interactions between different jets create so-called "working surfaces", where streams of gases collide and generate shock waves.>>
[quote="bcasa"]
it would be interesting if in the information some discussion was made as to approximately when this occured, since it is so many light years away, and how different it might look if you could see what it looks like now.[/quote]
The observed Herbig–Haro objects (from 5,000 lyrs away) no longer exist.
[quote=" http://en.wikipedia.org/wiki/Herbig-Haro_object"]
[float=right][img3="Images taken over five years reveal the motion of material in HH47."]http://upload.wikimedia.org/wikipedia/commons/8/86/HH47_animation.gif[/img3][/float]
<<Herbig–Haro objects (HH) are small patches of nebulosity associated with newly born stars, and are formed when gas ejected by young stars collides with clouds of gas and dust nearby at speeds of several hundred kilometres per second. Herbig–Haro objects are ubiquitous in star-forming regions, and several are often seen around a single star, aligned along its rotational axis.
[b][color=#FF0000]HH objects are transient phenomena, lasting not more than a few thousand years.[/color][/b] They can evolve visibly over quite short timescales as they move rapidly away from their parent star into the gas clouds in interstellar space (the interstellar medium or ISM). Hubble Space Telescope observations reveal complex evolution of HH objects over a few years, as parts of them fade while others brighten as they collide with clumpy material in the interstellar medium.
Spectroscopic observations of HH objects show they are moving away from the source stars at speeds of 100 to 1000 km/s. In recent years, the high optical resolution of Hubble Space Telescope observations has revealed the proper motion of many HH objects in observations spaced several years apart. These observations have also allowed estimates of the distances of some HH objects via the expansion parallax method.
As they move away from the parent star, HH objects evolve significantly, varying in brightness on timescales of a few years. Individual knots within an object may brighten and fade or disappear entirely, while new knots have been seen to appear. As well as changes caused by interactions with the ISM, interactions between jets moving at different speeds within HH objects also cause variations.
The eruption of jets from the parent stars occurs in pulses rather than as a steady stream. The pulses may produce jets of gas moving in the same direction but at different speeds, and interactions between different jets create so-called "working surfaces", where streams of gases collide and generate shock waves.>>[/quote]