Star survives close call with a black hole, researchers use ‘hot Jupiter’ data to mine exoplanet chemistry, and Dr. David Grinspoon talks his “Funky Science Story Hour”

A star that had a brush with a giant black hole and lived to tell the tale through exclamations of X-rays, Cornell astronomers have improved a model to gauge the temperatures of exoplanets, and Dr. David Grinspoon talks his “Funky Science Story Hour” on Facebook Live.

Transcript

This is the Daily Space for today, Monday, April 27, 2020. I am your host Dr. Pamela Gay, and I am here to put science in your brain.

Welcome to Monday. While this is generally the most hated day of the week, we are going to try to keep things light with Dr Funky Spoons, our PSI colleague David Grinspoon who is filling our plague times with science and laughter using FB Live. His Doctor Funky Spoon Funky Science Story Hours on Wednesdays are keeping it sciency for the kids, and he’s going to come on to talk about this cool program, and his other science and science communications activities. Before we bring on David, however, we’re going to take a look at the news.

Today we have a tale of two objects torn asunder, but not destroyed by the objects they orbit. In one case we have planets blasted by stars, and in another, we have a star shredded by a supermassive black hole.

Atmospheric gases recede from a “hot Jupiter,” which is a Jupiter-size, egg-shaped planet that orbits close to its own sun, in this artistic rendering. Cornell astronomers have developed a new mathematical model for determining temperatures on different parts of exoplanets, rather than averaging a planet’s temperature. CREDIT: Matthew Fondeur/Cornell University

Let’s start with “Hot Jupiters.” When you see something unexpected happen once, it can be seen as an outlier. When you see it 3 or 4 times, it indicates you may need to update your definition of unexpected. When the unexpected seems to be the norm… it’s time to rethink things. In recent years, scientists the world over have been working to directly determine the temperatures of exoplanets, and over and over, these alien worlds have appeared cooler than expected. This seems to indicate that planets must be holding onto heat differently from what was expected. Now, researchers at Cornell University have published a paper in the Astrophysical Journal Letters that uses updated models to try and get simulations to better match reality. In this work, led by Nikole Lewis, they reviewed more than 4100 detected exoplanets, looking for temperature measurements, and working to understand what they actually mean. One of the big issues is that we can’t generally disentangle the temperatures of the near and far side of these worlds – we often end up with an averaged measurement of the day and night time sides of the planet. This averaging can distort our understanding, and gives us a lower measurement than may be representative of the planet.

“Hot Jupiters” are worlds snuggled so close to their host stars that they orbit in just a few days, have one side permanently locked to face their star, and are blasted with so much energy that their day side can get distorted – bloating up, making the world look a bit like an egg, with the fat end facing the star.

When we look at these planets we can’t see their 3D shape, and if we try and transform from what we measure in the 2D sky to that 3D reality with the wrong assumptions, we’ll end up with temperatures that are 1000’s of degrees off. New models from Cornell look for specific key molecules in the planets’ atmospheres, and these molecules can more precisely indicate temperatures through both their existence, and their excitation levels.

These aren’t models we can easily use today – we just don’t generally have the telescopes and spectrographs needed to resolve molecules in most of these world’s atmospheres. But we can start… and when that next generation of space telescopes and massive earth-based scopes are built, we will be ready to more accurately understand their 3D temperature variations.

Getting too close to your host can be dangerous, no matter who or what you are. From planets too close to their host star, we now turn to a star getting too close to its host supermassive black hole.

CREDIT: X-ray: NASA/CXO/CSIC-INTA/G.Miniutti et al.; Illustration: NASA/CXC/M. Weiss;
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New X-Ray data from NASA’s Chandra and ESA’s XMM Newton X-Ray telescopes indicate a star in the galaxy GSN 069 got a bit too close, and is getting bites taken out every 9 hours or so, as it flies around this not entirely large supermassive black hole. At 400,000 Solar Masses, this system allows this star to get close enough to get bites removed without actually getting completely destroyed. In models by Andrew King of the University of Leicester, an everyday giant star wandered too close to the supermassive black hole for whatever reason, and had its atmosphere gravitationally torn away. Left behind is a white dwarf, a star that crams roughly a sun’s worth of material into a moon-sized volume of space. While the pull of gravity at the surface of this star is huge, it’s not enough to prevent the supermassive black hole from taking bites. Once per orbit, the star gets within 15 event horizon radii of the supermassive black hole. This occurs like clockwork every 9 hours. At this stage, it’s unclear how this system may be evolving, but with a thrice daily bite being taken, I’m hoping we’ll be able to see this star’s behaviors evolve over human lifetimes.

But for now, we just have to wait and see.

And that concludes our news for this low news day. But this doesn’t conclude our episode. I was able to interview Dr David Grinspoon live on twitch.tv and we’re now going to bring you that pre-recorded interview. As often happens, there were some technical glitches without live broadcast. Our guest’s audio starts low, but does improve a few minutes in. This week, we will be working to resolve these issues by updating our software configurations. For now though, let’s talk science with Dr. Funky Spoons.

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Thank you all for listening. Today’s script was written by Pamela Gay, and the Daily Space is produced by Susie Murph. The Daily Space is a product of the Planetary Science Institute, a 501(c)3 non profit dedicated to exploring our Solar System and beyond. We are here thanks to the generous contributions of people like you. The best way you can support us is through Patreon.com/cosmoquestx Like us? Please share us! You never know whose life you can change by adding a daily dose of science.