Podcaster: Fraser Cain
Title: Guide To Space – First Ever Picture of a Baby Planet!
Organization: Universe Today
Link: www.universetoday.com
Description: From Jul 4, 2018.
For the first time ever, astronomers have captured a direct image of a newly forming planet orbiting around a newly forming star. It’s a stunning photograph, not only for the science and what was observed, but what it means the future of exoplanetary astronomy.
Bio: Fraser Cain is the publisher of Universe Today
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Transcript:
It’s the 365 Days of Astronomy podcast, coming in 3, 2, 1. For the first time ever, astronomers have captured a direct image of a newly forming planet orbiting around a newly forming star. It’s a stunning photograph, not only for the science and what was observed, but what it means for the future of exoplanetary astronomy.
For the longest time, astronomers puzzled over how the planets in the Solar System formed. Did they form in place with the Sun, or were they somehow captured later on? There was no easy way to know, because we’re here, 4.5 billion years after the event took place. The leading theory was the idea that the entire Solar System formed at once from a giant cloud of hydrogen and helium left over from the Big Bang, as well as heavier elements seeded by nearby supernova explosions. Some event caused this cloud to collapse in on itself, and as it collapsed, it got hotter and denser. At the very core of this collapsing cloud was the region that would eventually become our Sun.
The combined motion of all the molecules in the cloud set it rotating as it sped up. It flattened out, like a spinning pizza. This was the Solar System’s protoplanetary disk.
Material in this disk clumped together into larger and larger grains, eventually forming asteroids and even planets. It was a pretty hectic and dangerous time, as objects smashed together, merging into larger objects. Then, as the newly forming Sun turned on, it blasted out powerful radiation that cleared out the intervening gas and dust, revealing the new Solar System to the Universe.
Or at least, that’s what astronomers thought happened. But the problem is that finding evidence for this has been difficult. We can see these protoplanetary nebulae across the Milky Way, but they’re shrouded in gas and dust that obscures visible light.
As astronomers demonstrated last week, technologies and techniques are pulling back that cloak and have shown us, for the first time, that planetary formation matches the theories. Astronomers used the European Southern Observatory’s Very Large Telescope to observe the newly forming planetary system, PDS 70. This is a 10 million year old dwarf star, with just a little less mass than the Sun.
It’s located about 370 light years from Earth, with a very wide protoplanetary disk that made it an ideal candidate for further study. In 2012, astronomers used the Near Infrared Instruments with the VLT to peer through the gas and dust that obscures visible light observations. They found a significant gap in the disk of PDS 70, but the problem was they couldn’t tell if the features in the disk were actually planets.
This made it the perfect candidate to study with a brand new instrument attached to the Very Large Telescope, called SPHERE. It saw its first light in 2014. SPHERE was used in 2015 to show an aging star giving birth to a planetary nebula, what our Sun will probably do billions of years from now.
It revealed incredibly detailed structures within a dusty disk around a nearby star, but it didn’t actually resolve planets. It mapped out the protoplanetary disks around other stars, showing how their planets carve out gaps in the disk, but again, no planets. SPHERE stands for the Spectropolarimetric High Contrast Exoplanet Research Instrument, another backronym, and how it works is pretty clever.
The instrument is equipped with a coronagraph, a region that blocks the light from the central star, revealing the fainter protoplanetary disk and the planet around it. When stars give off light, it’s unpolarized, which means that there’s no orientation to the photons going out into space. When those photons strike the atmosphere of a planet, some of them are partially polarized, similar to how polarized sunglasses will let some sunlight through, or 3D glasses will let different views of the same movie into your separate eyeballs.
SPHERE is designed to pick up this polarized light. Astronomers then took many exposures over many hours on two separate observing days. By aligning all the images together, they were able to remove anything that wasn’t moving.
What remained was the faint signal of a newly forming planet, PDS 70b. The planet, which has a few times the mass of Jupiter, inorbits the star at a distance of about 3 billion kilometers. That’s about the same distance as the Sun to Uranus, and it takes about 120 years to complete an orbit around the star.
Even at that distance, it’s hot, measuring about 1000 degrees Celsius, or 1200 Kelvin. Amazingly, astronomers were even able to detect that the planet has a cloudy atmosphere. The planet is moving within a large gap within the protoplanetary disk, which means that it’s probably still accumulating material, and will until the star’s stellar winds finally kick in and starve it of any more.
This is a stunning accomplishment. It shows how a ground-based observatory, like the Very Large Telescope, is able to directly observe extrasolar planets. It harnesses the most powerful telescopes in the world, using the right techniques and technology to do something that was thought only possible for a space telescope.
Just imagine what will be possible in the next few years when the next generation of super-telescopes are completed. The 24.5 meter Giant Magellan Telescope, the 30 meter telescope, and the 40 meter Extremely Large Telescope. This is just the beginning, I can’t wait to see what happens next.
And we will see all of you next week. Thanks everyone. You are listening to the 365 Days of Astronomy Podcast.
Cool.
[Speaker 2]
The 365 Days of Astronomy Podcast is produced by the Planetary Science Institute. Audio post-production is by me, Richard Drum. Project management is by Aviva Yamane.
And hosting is donated by LibSyn.com. This content is released under a Creative Commons Attribution, non-commercial 4.0 international license. Please share what you love, but don’t sell what’s free.
This show is made possible thanks to the generous donations of people like you. Please consider supporting our show on Patreon.com forward slash CosmoQuestX and get access to bonus content. Without your passion and contribution, we won’t be able to share the stories and inspire the worlds.
We invite you to join our community of storytellers and share your voice with listeners worldwide. As we wrap up today’s episode, we’re looking forward to unraveling more stories from the universe. With every new discovery from ground-based and space-based observatories, and each milestone in space exploration, we come closer to understanding the cosmos and our place within it.
Until next time, let the stars guide your curiosity.
End of podcast:
365 Days of Astronomy
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The 365 Days of Astronomy Podcast is produced by Planetary Science Institute. Audio post production by me, Richard Drumm, project management by Avivah Yamani, and hosting donated by libsyn.com. This content is released under a creative commons Attribution-NonCommercial 4.0 International license. Please share what you love but don’t sell what’s free.
This show is made possible thanks to the generous donations of people like you! Please consider supporting our show on Patreon.com/CosmoQuestX and get access to bonus content. Without your passion and contribution, we won’t be able to share the stories and inspire the worlds. We invite you to join our community of storytellers and share your voice with listeners worldwide.
As we wrap up today’s episode, we are looking forward to unravel more stories from the Universe. With every new discovery from ground-based and space-based observatories, and each milestone in space exploration, we come closer to understanding the cosmos and our place within it.
Until next time let the stars guide your curiosity