🔭 Hubble captures star birth in a giant cloud

A recent image from the Hubble telescope offers us a dive into the heart of N159, an immense stellar nursery where the cosmic spectacle of star birth unfolds in all its power.

Located about 160,000 light-years from Earth, in the constellation of Dorado, N159 belongs to the Large Magellanic Cloud. This dwarf galaxy, orbiting our own, is close enough for astronomers to scrutinize the mechanisms of star formation in great detail.


The scale of this cloud is truly gigantic: it spans over 150 light-years. To grasp such a size, one must imagine a distance nearly ten million times greater than that separating us from the Sun. These colossal dimensions allow such regions to generate a multitude of stars over millions of years.

Inside this cold cluster, mainly composed of hydrogen, gravitational force gradually draws gas toward increasingly dense centers. Subsequently, when these regions reach a certain mass, they collapse in on themselves, initiating the nuclear reactions that give life to new stars. These nascent stars then begin to shine while remaining embedded in the material that gave them birth.

The radiation from the most massive and hottest stars excites the surrounding hydrogen, causing it to glow with a characteristic red light. The Hubble telescope is particularly adept at detecting this emission, which allows scientists to map the areas where star formation activity is most intense. This ability opens a window onto the earliest stages of a star's existence.

The action of young stars is not limited to this light. Indeed, their energetic radiation and stellar winds, composed of particle streams, push back the surrounding gas, thus shaping bubbles and cavities within the cloud. This mechanism, called stellar feedback, can interrupt the formation of other nearby stars while potentially triggering new ones elsewhere, continuously reshaping the cosmic environment.

A recent Hubble observing campaign incorporated an additional wavelength into the image of N159, thereby enhancing the visibility of the hot gas surrounding the stars. This method offers a more precise view of how young stars modify their cradle over time.

Hydrogen, a fundamental element of the Universe

Hydrogen is the most abundant element in the Universe, representing about 75% of its atomic mass. Present from the first moments after the Big Bang, it holds a central place in the construction of cosmic structures. Within clouds like N159, it condenses under the effect of gravity to give rise to stars, serving as fuel for the nuclear reactions that power them.

Its simple atom, with a single proton and an electron, makes it sensitive to the extreme conditions of space. Under the effect of stellar radiation, it emits light of distinct colors, like the red captured by Hubble. This characteristic allows astronomers to trace its distribution and examine movements within stellar nurseries across galaxies.

Hydrogen exists in different states, notably molecular in cold clouds and ionized near hot stars. Its transformations throughout the stellar cycle influence the chemical evolution of the Universe, enriching the interstellar medium with heavier elements forged by stars. It thus forms a link between generations of stars and the growing structure of cosmic matter.