The James Webb Space Telescope is often said to be the successor to Hubble. This is both true, in the sense that it extends Hubble observations in the infrared with better resolutionresolution (which allows it to probe stratastrata of the oldest light in the history of cosmoscosmos observable) and false because Hubble can also make observations in the visible and ultraviolet, which the JWST does not allow. In fact, Hubble is still in high demand for observation time both for objects in the Solar System and for phenomena in galaxiesgalaxies distant, like supernovaesupernovae. We can even say that the James-Webb was designed to complement Hubble and not to replace it.
Hubble is therefore still with us for a good while, already because the Space Telescope Science Institute of Baltimore, Maryland (United States) contains 184 terabytes of processed and archived data that can be used by astrophysicistsastrophysicists of the future to obtain new information. These data correspond to 1.6 million observations of more than 53,000 astronomical objects. The result was 44,000 scientific articles on topics as diverse as supermassive black holes, atmospheresatmospheres of the exoplanetsexoplanetsTHE gravitational lensesgravitational lenses with the black matterblack matter and the existence and nature of dark energy.
This is what a press release from the NASANASA on the occasion of the 34e anniversary of the launch of Hubble by NASA on April 24, 1990. To celebrate this anniversary, the press release is accompanied by a sumptuous image of the nebulanebula du Petit Dumbbell (also known as Messier 76, M76 or NGCNGC 650/651) located at 3,400 light yearslight years of us in the constellationconstellation of Perseus. This is the kind of object that astronomersastronomers Amateurs can observe in particular with a Unistellar eVscope.
A video for Hubble’s 34 years of activity. To obtain a fairly accurate French translation, click on the white rectangle at the bottom right. English subtitles should then appear. Then click on the nut to the right of the rectangle, then on “Subtitles” and finally on “Automatically translate”. Choose “French”. © NASA’s Goddard Space Flight Center
A shell of plasma ejected by a dying star
As the NASA press release explains, the Little Dumbbell Nebula is classified as a planetary nebulaplanetary nebula but this has, in fact, no connection with the planets and the name dates back to the time of Charles MessierCharles Messier and its catalog of 110 deep sky objects of diffusediffuse (stellar clusters and nebulae in the sense of the time) that the astronomer had constituted after being burned by observations of these objects which could be confused with cometscomets. The instruments of the time only gave blurry images of what could have been for the scientists of the time the planets. More precisely, it is because these fuzzy objects cataloged by Messier three centuries ago looked a lot like UranusUranus in the telescopes that William HerschelWilliam Herschel called them planetary nebulae.
In the case of Messier 76, we now know that we are observing an expanding plasma shell ejected by the instabilities eruptiveeruptive of a giant stargiant star dying red that ended up becoming a white dwarfwhite dwarf ultra-dense and hot whose surface temperature is approximately 138,000 kelvinskelvinsor almost 24 times the surface temperature of our SunSun. This shell will soon dissipate quickly, on the time scale of the Milky WayMilky Waythat is to say within approximately 15,000 years.
NASA comments on the Hubble image in these terms:
“ M76 is composed of a ring, seen from the edge as the structure of the central bar, and two lobes on each opening of the ring. Before the star went out, it ejected the ring from gasgas and dust. The ring was probably sculpted by the effects of the star that once had a companion star binarybinary. This removed material created a thick disk of dust and gas along the plane of theorbitorbit of the companion. The hypothetical companion star is not visible in the Hubble image and could therefore have been swallowed later by the central star. The disk would constitute forensic evidence of this stellar cannibalism.
Pinched by the disk, two lobes of hot gas escape from the top and bottom of the “belt”, along the axis of rotation of the star which is perpendicular to the disk. They are propelled by a flow of material similar to a hurricanehurricane coming from the dying star, crossing space at three million kilometers per hour. It’s fast enough to travel from Earth to MoonMoon in just over seven minutes! This ” windwind “starburst” torrential rains down on cooler, slower gas that was ejected at an earlier stage in the star’s life, when it was a red giant. Ultraviolet radiation from the super-hot star causes the gases to glow. There colorcolor red comes fromnitrogennitrogen and the blue ofoxygenoxygen. »
