Intéressant Merci !!
Effectivement ça confirme donc ce que je pensai initialement, mais un message m'a mis le doute sur notre forum, une personne affirmant que c'était Betelgeuse, et qu'il ne falait pas venir lui dire que c'etais une "ejection de masse coronale", car d'après lui ça n'en était absolument pas.
Bon maintenant je suis sur
) Merci à vous pour votre confirmation et votre sérieux.
. Voici les 2 derniers échange avec l'ami Joe de la nasa suite au précédent mail :
---- moi -> Joe
Hello, Mr Gurman,
Thank you very much for this informations !
I havent find the page about what is "CDD Backout" and now i understand better, the CDD is used also to soho telemetrie guidance from earth. During this time, the mecanisme cant send photography of the sun because it is fully used for guidance opérations.
My initial question is about the CME, because i think it is "strange" CME we have here !
When i look photographie with stéréo Lagrange L5 during 11/08/09 16hTU to 11/08/09 19h54TU, i view that the "light" becoming stronger when it is distanting, and not also luminous when it is just start expanding from sun surface.
For me, a CME cant be "more" and "more" luminous like this evenement, or this is "strange" ... And in my first view, i have thinking also about betelgueuse position on the picture... If the light was and gaz expantioin from Betelgeuse, view by Stéréo L5 Satellite ?
So i am investigating about the real position of Stéréo at time of the photographie.
I know the angle of 60° for L5 / L4 between Lagrange point -> sun > earth, but i dont know the angle of the stéréo satellites between ecliptyque.
The difference is important because, if the satellite il +15° pitch above the ecliptique, and 60° angle between L5 > sun > earth, that is the vue i have calculated on celestia :
But if the satellite is ON the ecliptique, and same 60° yaw, and 0° pitch, that is the vue :
So, if we are in the first case, it's possible that what we see around the sun was Betelgeuse !
This is why about my initial question.
But i am not astro-physicien, i am an amateur, and i have justs notions about aéronautique navigation, and this is why i am asking you.
If you have a response about the exact position of Stéréo in L5, and if Betelgeuse was in the axis like "first case" or not, that can really interrested me and our community of amateurs astronomes.
Thank you for your initial response !
Meilleurs voeux également
Et la réponse :
STEREO spacecraft locations:
No, it's certainly not an emanation from Betelgeuse or any other distant star. That would expanding very, very superluminally if we actually saw it as an expansion within that short a time from within the solar system.
I can't state definitively that this is an explanation for what you see, but the intensity of features just outside the "occulting disk" at the center of the COR2 images is very dependent both on a model of the vignetting and the pointing of the spacecraft. Thus object just "above" the occulting disk may appear fainter than they really are.
As you can see, there is some "stray" light leaking our above the northeast (~ 10 - 12 o'clock position) part of the occulting disk; I believe the images are treated to reduce intensities near the occulting disk to prevent this stray light swamping the coronal signature. Coronal features are 10^9 times or more fainter than the surface of the Sun in visible wavelengths.
Also, since the coronal emission is optically thin, if more emitting or scattering material is visible along the line of sight (and near the plane of the sky for a polarized brightness (pB) image, a given pixel will appear brighter; similarly if the scattering electrons move closer to the plane of the sky. An eruption from somewhere on the "left" half of the invisible hemisphere of the Sun (the visible hemisphere is currently quite quiet) as seen by STEREO B might also be carried toward the plane of the sky by solar rotation.
Voila donc il confirme que ce que l'on a vu est bien une éjection de masse coronale et non pas Betelgeuse (si j'ai bien compris sa réponse).