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The Nebula IC 443 and its neutron star Cocorico !

IC 443 (Source: Chandra)

This wonderful image of the nebula IC 443 was realized by the Satellite Chandra, on January 12th, 2005 then published on Internet on June 01st, 2006.

It is a composite picture.

Wavelengths

X Radio Visible

Restored in

Blue Green Red

This nebula, residue of a supernova, situated at approximately 5000 light years from the solar system, presents surprising peculiarities:

  1. It appears in the form of a turbulent and expanding bubble of gas emitting in visible light, in X-ray and also in radio.

  2. Within there is, a neutron star, what would be a commonplace except that this object is totally off-center. This could be explained if it has a specific speed acquired during or after the initial event causing the formation of this supernova. In this hypothesis we should find, in the image of the nebula, evident tracks of the movement of the neutron star. But it is not the case.

  3. A collimated jet which seems stemming from the neutron star.

  4. Some astronomers seem to have revealed the existence of a pulsar.

We suggest examining these peculiarities.

Zoom in IC 443 (Source: Chandra)

Zoom on the neutron star J0617 and on the surrounding regions.

  1. The neutron star is in a turbulent region. It emits towards the left a collimated jet almost rectilinear, visible in Xray (Blue).

  2. It also seems to eject towards the right-hand side a turbulent plume of matter detected in visible radiation. (Red).

Are they illusions due to a particular geometrical configuration of these objects?

  1. To make it sure we make a digital processing of this image.
    The collimated jet is then perfectly confirmed.

  2. The turbulent plume is not only confirmed, but we realize that it seems to come directly from the neutron star.

  3. There also seems be a plume towards the left. But nothing, in these images, allows to connect it directly with the jet or with the neutron star.

Zoom + Traitement informatique sur IC 443

The Neutron Star J0617 in X ray

  1. The X-ray image, of the neutron star seems to show that this star is in reality a double object.
    Would it be due to an artefact of the camera of Chandra?

J0617 (Source: Chandra)

The composite image (zoom), opposite, seems to confirm that it is really a double system..
In fact, what at first we thought be a simple neutron star, turns out be a very complex system.

Diagram

Let us establish a plan to facilitate the analysis.

We observe that :

Objects

Comments

A This object appeared thanks to the zoom.
B+B' The neutron star is clearly double
C Is this object a part of the system?
D This object seems connected with B+B' by a filament.
Bridge of matter This bridge of matter situated inside the ellipse, in red in the diagram, seems to connect  B+B' to A
Bubble of gaz It appears in X-ray and in radio waves. It wraps the whole system (ellipse in dotted lines in the diagram).
Plume Bounded in the diagram by the blue dotted lines, It seems stemming from B+B'.
Jet And now the surprise, the jet does not arise from B+B' but very clearly from the object A. And furthermore this jet, if it is collimated, presents curious characteristics, such as inexplicable breaks and a curvature.
Shock wave In the axis of the bridge of matter stemming from B+B', and close to A, there seems to be a shock wave (spotted in the diagram by the arc of a circle).

Questions:

  1. Which of these objects A, B, B' is the neutron star?
  2. Which of these objects could be the pulsar?
  3. Are all these objects neuron stars, or even pulsars?
  4. What is the real nature of the shock wave?

Zoom on J0617 (DP Image)

To try to answer to some of these questions, we made a digital processing on the image supplied by Chandra.

  1. The jet appears mashed up, under the shape of almost periodic waves. Let us note that this phenomenon is rather frequent in the jets. We can, among others, cite the example of the jet of the galaxy M 87.

  2. The jet arises from A, but with a first break near A, then a second one farther away. It presents a very net curvature. Let us note that curiously the extremity of the jet is almost exactly in the continuation of the axis BA.

  3. The plume clearly arises from the region B+B'.

Diagram of the Dynamic

Now we can establish a first sketch of the dynamics of the gas (plasmas?) in this system.

Objects

Comments and hypotheses

Bridge of Matter Stemming from B+B', it seems that it would be constituted by a warm plasma (protons + electrons?) and that this plasma would be thrown, partially, towards A. The magnétosphère of A, would divert the particles of this plasma (forming what appears to us as a shock wave). Beyond A these would then be accelerated and collimated. In this way they would form a jet. We cannot avoid comparing this with the solar wind and the Earth magnetosphere.
Plume It seems stemming from B+B', or of their close environment. But is it really an ejection either, on the contrary, an accretion of matter?
Filament In green in the diagram above, it is possible that it is only an artefact. Its orientation is thus, at least, doubtful..
Jet Stemming from A, its orientation raises no problem. On the other hand, we have no obvious explanations for the breaks and the curvature of its trajectory.

Structure of the Crab Pulsar

We have already seen a jet, in the environment of the Crab pulsar (M1), presenting a break very similar to this one. And we had shown that it could involve the effect of refraction in a bubble of gas having a gradient of refractive index, and in which there are travelling density waves.
Could there be a similar phenomenon in the environment of the IC 443 "neutron star"?
Object B+B' would be a double image as a result of an effect of refringence around a neutron star (pulsar?). (See [1] and [2] in the bibliography below).
In this case, we would be in the presence of a system of several bubbles. It is indeed what the images, brought by Chandra, seem to suggest.

Bibliography :

  1. Jets et Systèmes binaires - Bernard Lempel. L'Astronomie Vol 117 - Sept 2003. SAF. (PDF=1,6 Mo)
    Jets and binary Systems - Bernard Lempel. (The same as previous, but translated from French) (PDF, 588 Ko)

  2. Le pulsar du Crabe, Faits et Contradictions. (French)

  3. The X-Ray structure of the pulsar bow shock G189.22+2.90 in the supernova remnant IC 443-B. (M. Gaensler, & al) - arXiv:astro-ph/0601304 v2.

  4. Cluster, Explosions, Plasmoids, Ion Beams - Report on 7th Cluster Workshop (ESA 15-Mar-2004)

  5. Les sous orages et le champ magnétique.

  6. Séminaire sur les Supernova, à l'occasion du  400ème anniversaire de la Supernova de Kepler  du 9 Octobre 1604, Organized by the Institute of Astrophysics of Paris (IAP). (Report wrote by Jean-Pierre Martin).

  7. The Mouse that soared G359.23-0.82: A magnificent confirmation by Chandra of the structure and the mechanism of pulsars (stellar Wind + Magnetosphere + Jet)

 

Creation Date: 15/08/2006 
Last Release: 11/08/13

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