Salzburg: World’s first image of a newly discovered planetary nebula
Strottner-Drechsler 31 is a spectroscopically confirmed planetary nebula in the constellation Serpent. It was discovered in 2020 by the Franco-German research team Marcel Drechsler and Xavier Strottner. The Salzburg astrophotographer Rochus Hess can now show the world what this celestial object looks like. His recording of “StDr31” was taken at the “VEGA Observatory House of Nature”.
The message in full:
Salzburg – The Salzburg astrophotographer Rochus Hess once again succeeded in photographing a recently discovered planetary nebula by the research team Drechsler-Strottner – which is why he has now given the nebula its name: The proper name of the planetary nebula “StDr31” is now “Rochus’ Blossom Nebula “(“Rochus’ Blossom Mist”). Planetary nebulae mark the final stages of dying stars. They are – thought in cosmic dimensions – fleeting phenomena and only exist for a few tens of thousands of years. Since 2019, the two amateur astronomers Xavier Strottner and Marcel Drechsler have been cataloging the planetary nebula in a freely accessible database. They have now documented about 140 of these objects. After systematically searching sky images, they identify areas with evidence of planetary nebulae. This is followed by a spectroscopic analysis, which confirms the nebulae, but their appearance remains completely obscure. In order to get a picture of the discovered planetary nebulae, the two work together with the world’s best astrophotographers – one of them is Rochus Hess from Salzburg.
Rochus Hess has been a member of the working group for astronomy at the Haus der Natur for many years and has been doing astrophotography at a scientific level for over 25 years. He concentrates primarily on objects outside our solar system, with the powerful 1-meter reflecting telescope at the “VEGA Observatory Haus der Natur”, which was built in 2018, opening up new possibilities for him. “Rochus’ Blossom Nebula” is the second recording within a short period of time to be released in recognized by the international professional world. In June 2020, Hess received the coordinates of the nebula from Marcel Drechsler. Since this object is never very high above the horizon in our latitudes and can only be observed well in the months of June and July, it was not easy to collect enough exposure time – the summer nights are short. Although this project has been extended over two years, the total exposure time of the image is only 4.5 hours, a lower value in astrophotography. “The short nights and the low level of fog over the horizon were a real challenge. When I was about to give up, Marcel Drechsler motivated me to keep going,” Rochus Hess says gratefully.
How is a planetary nebula formed?
The image shows a glowing cloud of gas produced by a dying star that is gradually shedding its outer layers into space at the end of its life. As the star exposes its always-hot core, it changes color from orange to yellow to white to finally blue. When its surface is around 30,000 Kelvin, high-energy photons are emitted that ionize the ejected gas. The gas shell becomes visible, the star in the center has reached the stadium of a white dwarf.
Astrophotography: Making a celestial object visible
Hess: “For me, making the invisible visible is so fascinating about astrophotography. It is only through the extremely long exposure times that the wonderful colors and structures come to the fore.” Hess used an astro CCD camera with cooled camera sensor to minimize electronic noise. He created many individual exposures, which he then processed digitally with special software. Only then did the details gradually become visible. In the summer of 2022, Hess was able to successfully complete the project. However, Strottner, Drechsler and Hess will continue to hunt for previously unknown objects in space in the future.
Press Release House of Nature, Museum of Nature and Technology