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#vega
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#CalendrierdelAventEspace des images remarquables de 2024.
Le 5 septembre, c'était le dernier lancement de la fusée #Vega.
Le lanceur a mis sur orbite le satellite d'observation de la Terre européen Sentinel 2C.
En savoir plus : https://reves-d-espace.com/ultime-mission-reussie-pour-vega-le-satellite-sentinel-2c-rejoint-la-constellation-copernicus/
A un peu plus d'une semaine du décollage (prévu le 3 décembre), le satellite #Sentinel1 C a été placé sous sa coiffe de protection.
Bientôt il ira rejoindre le lanceur #Vega #VV25 sur le pas de tir.
ESA – M. Pédoussaut
Continued thread
GIF
Hubble and #JWST get a very clear view of Vega.
It's a mysterious system because it's unlike other circumstellar disks. The #Vega disk is smooth, ridiculously smooth.
There is no obvious evidence for one or more large #planets plowing through the face-on #disk like snow tractors.
The Vega disk does have a subtle gap, around 60 AU from the #star, but otherwise is very smooth all the way in until it is lost in the glare of the star.
#astronomy #exoplanets
https://phys.org/news/2024-11-hubble-webb-probe-smooth-disk.html
phys.orgHubble and Webb probe surprisingly smooth disk around VegaIn the 1997 movie "Contact," adapted from Carl Sagan's 1985 novel, the lead character scientist Ellie Arroway (played by actor Jodi Foster) takes a space-alien-built wormhole ride to the star Vega. She emerges inside a snowstorm of debris encircling the star—but no obvious planets are visible.
Berühmter Stern verblüfft Astronomen. Die Vega überrascht durch ihre glatte Staubscheibe und das Fehlen von Planeten. #Vega #Wega #Stern #Staubscheibe #Astronomie #JWST #Hubble
https://www.scinexx.de/news/kosmos/beruehmter-stern-verbluefft-astronomen/
scinexx | Das Wissensmagazin · Berühmter Stern verblüfft AstronomenÜberraschende Entdeckung: Der nur 25 Lichtjahre entfernte Stern Vega hat offenbar keine größeren Planeten – und eine verblüffend gleichmäßige, glatte
Today on the arXiv:
Su et al. 2024, "Imaging of the Vega Debris System using JWST/MIRI" - https://arxiv.org/abs/2410.23636
Wolff et al. 2024, "Deep Search for a scattered light dust halo around Vega with the Hubble Space Telescope" - https://arxiv.org/abs/2410.24042
Presenting complementary observations that exclude any planets larger than Neptune around #Vega , down to below 6 Earth masses for some orbits, despite the debris disc.
The authors compare to the case of #Fomalhaut .
arXiv.orgImaging of the Vega Debris System using JWST/MIRIWe present images of the Vega planetary debris disk obtained at 15.5, 23, and 25.5 microns with the Mid-Infrared Instrument (MIRI) on JWST. The debris system is remarkably symmetric and smooth, and centered accurately on the star. There is a broad Kuiper-belt-analog ring at 80 to 170 au that coincides with the planetesimal belt detected with ALMA at 1.34 mm. The interior of the broad belt is filled with warm debris that shines most efficiently at mid-infrared along with a shallow flux dip/gap at 60 au from the star. These qualitative characteristics argue against any Saturn-mass planets orbiting the star outside of about 10 au assuming the unseen planet would be embedded in the very broad planetesimal disk from a few to hundred au. We find that the distribution of dust detected interior to the broad outer belt is consistent with grains being dragged inward by the Poynting-Robertson effect. Tighter constraints can be derived for planets in specific locations, for example any planet shepherding the inner edge of the outer belt is likely to be less than 6 Earth masses. The disk surface brightness profile along with the available infrared photometry suggest a disk inner edge near 3-5 au, disconnected from the sub-au region that gives rise to the hot near-infrared excess. The gap between the hot, sub-au zone and the inner edge of the warm debris might be shepherded by a modest mass, Neptune-size planet.
#ESA:
"A redesigned Zefiro-40 solid rocket motor, the second stage of the Vega-C rocket, was successfully fired up .. at its Salto di Quirra test facility in Sardinia, Italy. This second firing follows from a first firing test of the motor in May 2024 and concludes the qualification tests for the improved engine nozzle design of the Zefiro-40."
3.10.2024
www.esa.intLast rocket motor firing clears path for Vega-C launch
L'ultime mission du lanceur #Vega a mis sur orbite le satellite #Sentinel2C du programme européen Copernicus.
Mon article : https://reves-d-espace.com/ultime-mission-reussie-pour-vega-le-satellite-sentinel-2c-rejoint-la-constellation-copernicus/
Continued thread
Tout d'abord, on a dit ciao à #Vega. Le lanceur léger de l'ESA a pris son dernier envol avec succès depuis le Centre spatial guyanais dans la nuit du 5 septembre. Sa mission était de mettre en orbite le satellite Sentinel-2C, qui fournira des données essentielles au programme européen Copernicus 
Succès de la #Vega #VV24 la nuit dernière. Pour sa dernière mission, elle a placé sur orbite basse le satellite #Sentinel2C du programme européen Copernicus.
Le centre de contrôle de l'ESA a reçu les premières télémesures et confirme le déploiement du panneau solaire.
ESA/CNES/Arianespace
Nuit de lancement - nouvelle tentative #Vega (la dernière !) #VV24 Satellite d'observation de la Terre européen #Sentinel2C
1h50 UTC - 3h50 heure de Paris
Centre Spatial Guyanais ESA
https://www.esa.int/ESA_Multimedia/ESA_Web_TV/(offset)/2
Continued thread
Nouvelle tentative de lancement cette nuit, même horaire, même lien 
#lancement #fusée #Vega #Sentinel2
Let's go! #Sentinel2 launch on #Vega 
Next launch attempt in about 12 hours 
on 03:50 CEST on 5 September. Watch here:
www.esa.intWatch Sentinel-2C launch live on the final Vega rocketThe Copernicus Sentinel-2C satellite is ready for liftoff! Tune in to ESA WebTV on 4 September from 03:30 CEST to watch the satellite soar into space on the last Vega rocket to be launched from Europe’s Spaceport in Kourou, French Guiana. Sentinel-2C is scheduled to liftoff at 03:50 CEST.
Most modern #Research in fields such as the #Environment, #Climate or #Agriculture somehow depend on #EarthObservation products from #Sensors that #VEGA put in orbit.
Nuit de lancement #Vega (la dernière !) #VV24 Satellite d'observation de la Terre européen #Sentinel2C 1h50 UTC - 3h50 heure de Lille Centre Spatial Guyanais ESA https://www.esa.int/ESA_Multimedia/ESA_Web_TV/(offset)/2
Et voilà #Vega #VV24 est complétement assemblée avec sous la coiffe, le satellite d'observation #Sentinel2C de l'ESA.
Décollage prévu le 4septembre.
ESA-CNES-ARIANESPACE/Optique vidéo du CSG–T. Leduc
Le satellite #Sentinel2C est sous coiffe ! Il sera lancé le 4 septembre par la dernière #Vega #VV24. Il doit remplacer le satellite Sentinel-2A à une altitude de 786 km pour l'observation de la Terre et ses applications dérivées comme l'agriculture de précision, la surveillance de la qualité de l’eau et la gestion des catastrophes naturelles ESA/Airbus Space
Sentinel-2C sealed in the Vega rocket fairing.
www.esa.intSentinel-2C sealed in the Vega rocket fairingAs preparations continue to launch the Copernicus Sentinel-2C satellite on 4 September, the team at Europe’s Spaceport in Kourou, French Guiana, has bid farewell to their precious satellite as it was sealed from view within the Vega rocket fairing.