.....::    fonte.es     2021-09-02

Créditos: Hubble (ESA-NASA)

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In the photo below - recently taken by Hubble - we see one of those strange objects that exist in our galaxy. The set impresses with both color and appearance. They are called Herbig-Haro systems and consist of very young stars that were born very close together in one of the many clouds of gas and dust found in the vicinity of the Orion Belt (in the constellation of the Archer, specifically the cloud L1617). It seems that there are two stars dancing very tight at breakneck speeds and that they are accompanied from afar by another. His name is HH 111.

The system is 1,360 light-years from us and the jet is believed to have formed just 800 years ago. It is 12 light-years long at both poles, as much as three times the distance from the Sun to alpha-Centaur, the closest star to us.

It is not well perceived, but behind the main jet is another smaller, reddish one, the HH-121. According to astronomers, both come out of a vortex caused by the combination resulting from an intense gravitational pull between the stars which on the other hand are very hot and spinning like crazy in an intense magnetic field.







New stars are usually very active, and in some cases emit very narrow jets of fast-moving ionized gas, a gas so hot that its molecules and atoms lose electrons. This causes it to charge and glow brightly. The bright smoke appears to have denser areas than others, such as mouthfuls. If photos taken with sufficient time separation are compared, it is estimated that it moves at about 300 km per second, at the beginning and then brakes. It appears that this gas receives linear momentum from the stellar system without the intervention of the magnetic field of the star provided by the material, which seems to contradict some widely recognized theories.

The different colors of the image are obtained by means of filters that are placed in front of the lenses of the telescope. They are then combined by computer to extract information about the composition of the object. Using this technique, researchers know that the reddest areas correspond to ionized molecular hydrogen (which glows outside the visible spectrum but are perfectly perceived by photographic sensors), the blues are ammonia perhaps mixed with nitrogen and sulfur, and the browns and Yellows are mostly carbon and simple molecules that contain this element. The currents glow even brighter when they collide with the gas surrounding the nebula.

The stars involved in this unique phenomenon are surrounded by a toroidal disk of material that absorbs much of the radiation they emit, so they are not clearly visible. To avoid this drawback, the new HH-111 image was obtained from separate exposures that were taken in the infrared region of the spectrum with Hubble's wide field 3 camera (WFC3).







In the previous image, two Herbig-Haro objects in the rich Carina (or Keel) nebula, another area of ​​abundant star formation.

Na fotografía inferior -recentemente sacada polo Hubble- vemos un deses estraños obxectos que existen na nosa galaxia. O conxunto impresiona tanto polo colorido como polo aspecto. Chámanse sistemas Herbig-Haro e consisten en estrelas moi novas que naceron moi xuntas dentro dunha das moitas nubes de gas e po que se atopan nas inmediacións do Cinto de Orión (na constelación do Arqueiro, en concreto a nube L1617). Parece que hai dúas estrelas que danzan moi cinguidas a velocidades vertixinosas e que están acompañadas de lonxe por outra. O seu nome é HH 111.

O sistema atópase a 1.360 años luz de nós e crese que o chorro se formou hai tan só 800 anos. Ten unha lonxitude de 12 anos-luz por ambos polos, tanto como tres veces a distancia dende o Sol ata alfa-Centauro, a estrela que nos queda máis próxima.

Non se percibe ben, pero por detrás do chorro principal hai outro máis pequeno e roxiño, o HH-121. A xuízo dos astrónomos, ambos saen dun remuíño causado pola combinación resultante dunha intensa atracción gravitatoria entre as estrelas que, por outra banda están moi quentes e xirando coma tolas nun campo magnético intenso.







As novas estrelas adoitan ser moi activas e, nalgúns casos, expulsan chorros moi estreitos de gas ionizado en movemento rápido, un gas tan quente que as súas moléculas e átomos perden electróns. Isto fai que se cargue e brille intensamente. A brillante fumeira aparenta ter unhas zonas máis densas ca outras, coma bocaladas. Se se comparan fotos tomadas cunha separación de tempo suficiente, calcúlase que se despraza a uns 300 km por segundo, no inicio e despois fréase. Parece ser que este gas recibe impulso lineal do sistema estelar sen intervir o campo magnético da estrela que aporta o material, cousa que parece contradicir algunhas teorías amplamente recoñecidas.

As distintas cores da imaxe obtéñense mediante filtros que se colocan diante das lentes do telescopio. Despois combínanse por ordenador para extraer información sobre a composición do obxecto. Mediante esta técnica, os investigadores saben que as zonas máis avermelladas correspóndense con hidróxeno molecular ionizado (que brilla fóra do espectro visible pero que perciben perfectamente os sensores fotográficos), as azuis son de amoníaco tal vez mesturado con nitróxeno e xofre, e as pardas e amarelas son principalmente de carbono e de moléculas simples que conteñen este elemento. As correntes brillan aínda máis cando chocan contra o gas que circunda á nebulosa.

As estrelas implicadas neste singular fenómeno están rodeadas dun disco toroidal de material que absorbe unha gran parte da radiación que emiten, polo que non se deixan ver con claridade. Para evitar este inconveniente, a nova imaxe de HH-111 obtívose a partir de exposicións separadas que foron tomadas na rexión infravermella do espectro coa cámara amplo campo 3 (WFC3) do Hubble.







Na imaxe precedente, dous obxectos Herbig-Haro na rica nebulosa de Carina (ou da Quilla), outra zona de abundante formación estelar.