We observe the edges of the structure as well-known nebulae, which include Barnard’s Loop and the Horse’s Head (both in the image on the left), or fine hydrogen filaments stretching to the constellation Eridanus, where the giant Loop in Eridanus is located (in the image on the right).
The glowing structures represent the boundaries of a vast nebular complex where hot, thin gas collides with the cooler interstellar medium.
Ancient stellar explosions
The Orion–Eridanus Superbubble (orion-Eridanus Superbubble) was created as a remnant of the ancient activity of massive stars, whose explosions and subsequent strong shock waves fundamentally deformed the given area.
The huge structure was formed as a result of ten to twenty supernova explosions and a strong stellar wind. Over several generations of stars, these processes blew away the surrounding gas and created a cavity hundreds of light-years across.
“Physically, it can occupy 300-500 light-years on average. Our Solar System would therefore fit several hundred times in it,” said astronomer Jakub Kuřák.
“The actual extent of the bubble is difficult to imagine: at its widest point, the Orion–Eridanus superbubble stretches across the sky at an angle of around 45 degrees, which corresponds to 90 lunar full moons next to each other,” he further described on the website of the Czech-Slovak Astronomical Press Agency.
How to photograph invisible objects
According to astronomers, the bubble is an impressive reminder that even the seemingly empty space between the stars has its own rich history. Thanks to modern methods of astrophotography, it is now possible to capture this structure and present it to the public.
The photographer captured the resulting image at several observation sites in Liberecko during clear nights between January 12 and 16 using a sensitive camera and a specialized H-alpha filter. This mainly isolates the wavelength of ionized hydrogen. He had to expose the captured data for over five and a half hours and then process them mathematically.
“Looking at these structures, we realize that very ancient stellar explosions still shape the environment in which new generations of stars are born today,” concluded Jakub Kuřák from Smržovka in Jabloneck, who otherwise works as a popularizer of astronomy in Liberec’s IQLandia and devotes himself to astrophotography in his spare time.
As an astrophotographer, he has already twice succeeded in selecting the Astronomical Image of the Day by the American space agency NASA.
