Podcaster: Tony Darnell
Title: Deep Astronomy – Exoplanet Radio – 37: Osiris: The Exoplanet That Changed Everything
Organization: Deep Astronomy
Link : https://deepastronomy.space
Twitter @DeepAstronomy, https://facebook.com/DeepAstronomy
YouTube: https://www.youtube.com/deepastronomy
Description: From Oct 2, 2023.
The planet is HD 209458 b, and nicknamed “Osiris” after the Egyptian god of the underworld. Osiris is a fitting nickname for this planet, as it is a very hot and hostile world. HD 209458 b orbits its star very closely, and its surface temperature is estimated to be around 1,000 degrees Celsius. This makes it too hot for liquid water to exist on its surface, and it is unlikely to be habitable. Even so, this planet is remarkable in many ways. It occupies first place in a long list of discovery milestones.
Bio: Tony Darnell is the owner of Deep Astronomy website and a host for the same hangout channel in Youtube. He has worked in the field of astronomy all my life, his first job was at a school district planetarium in Boulder, Colorado. With the exception of a stint in the Army in the 1980’s he has worked in many aspects of astronomical research.
Most of his time has been spent writing software to retrieve, process and analyze data taken from telescopes. He has worked with data from some of the world’s largest ground-based and space-based telescopes: from the four meter Blanco telescope in Chile to the Hubble Space Telescope.
Astronomy education has always been his passion and he has written articles for DeepAstronomy.space website and produce astronomy videos for YouTube on the DeepAstronomy channel.
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Transcript:
This is Exoplanet Radio. I’m Tony Darnell.
On September 9, 1999, a team of astronomers from the High Altitude Observatory made a groundbreaking discovery. Using the radial velocity method, they detected a massive Jupiter-sized planet orbiting a sun-like star, HD 209458. This was the first exoplanet to be discovered using this method, and since that fateful day, this system has become a champion of firsts.
The planet is HD 209458 b, and nicknamed Osiris after the Egyptian god of the underworld. Osiris is a fitting nickname for this planet, as it is a very hot and hostile world. HD 209458 b orbits its star very closely, and its surface temperature is estimated to be around 1,000 degrees Celsius.
This makes it too hot for liquid water to exist on its surface, and it is unlikely to be habitable. Even so, this planet is remarkable in many ways. It occupies first place in a long list of discovery milestones.
Here are some of the areas Osiris occupies first place. It is one of the first exoplanets to be discovered using the transit method, which means that astronomers were able to detect it by observing how its star’s light dimmed as the planet passed in front of it. This was a major breakthrough, as it showed that it was possible to directly detect exoplanets.
In fact, seeing its transit makes it the first exoplanet to be detected by more than one method, both transit and radial velocity. Further, it was the first planet to have its orbital speed measured, allowing astronomers to determine its mass directly. Osiris is also the first exoplanet to have its atmosphere directly detected.
In 2001, astronomers using the Hubble Space Telescope were able to measure the absorption of light from HD 209458 b’s atmosphere. This allowed them to identify the presence of sodium and other elements. And in 2007, astronomers from the Lowell Observatory found evidence of water vapor in the upper atmosphere, another first.
These observations were a major breakthrough in exoplanetary research. It showed that it was possible to learn more about the composition of exoplanet atmospheres and to search for biosignatures, which are molecules that could be indicative of life. Osiris is also the first exoplanet to be observed losing its atmosphere.
Astronomers have detected a large plume of hydrogen gas escaping from the planet. This is likely due to the intense heat and stellar winds from the star stripping it away, leaving a stream of material behind it. The discovery of the evaporating atmosphere showed that some exoplanets could actually lose their atmospheres.
And this could have a significant impact on their habitability. This exoplanet, some 157 light years away, has single-handedly had a profound impact on our understanding of exoplanets and the search for life beyond Earth. It has advanced our understanding of other worlds outside our solar system, perhaps more than any other exoplanet we’ve seen.
It has shown that it is possible to directly detect exoplanets and their atmospheres, find out what they’re made of, and that some exoplanets are actually losing their atmospheres. The discovery of HD 209458b was a major inspiration for the search for life beyond Earth. Astronomers now realized what was possible when studying other worlds in the distant galaxy.
Although OSIRIS is not a good candidate for life, its discovery showed that there may be many other exoplanets out there that are more habitable. Exoplanet Radio is produced by Deep Astronomy. The music is by Geodesium and available at LochNessProductions.com.
Get all episodes from ExoplanetRadio.com or anywhere you get podcasts.
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365 Days of Astronomy
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