EVSN - Daily Space Planets, Stars & Death to Dark Energy

It's the 365 days of Astronomy PodGam, coming in 3, 2, 1.

Hello, this is the Daily Space for Today, Tuesday, January 7, 2020.

I am your host, Suzy Murth, and I am here to put science in your brain.

Yesterday's breaking news more than compensated for the past few weeks of slow news,

from turning lead into gold with neutron star mergers to discovering Earth-like planet,

to learning about a star that will explode in the lifetime of some of our younger audience members,

today's news goes on and on and on.

While all of us have been eagerly awaiting to see if Beetlejuice will go boom,

a team of astronomers from Louisiana State University have been calculating the explosion date of a different system,

V. Sagittay.

This research was presented by Brad Schaefer, and done in collaboration with Duhon Frank and Menos Chatspullis.

Stars self-destruct in a variety of ways.

Some of them explode as a result of a sudden collapse when they run out of nuclear fuels.

Some of them explode when they eat too much of a neighboring star and collapse under the weight of excess mass.

And sometimes, stars spiral together and burst as they merge,

such as was seen in the Killanova event with two merging neutron stars in 2017.

The event this team is predicting for V. Sagittay isn't any of these kind of events.

It is instead something that will happen when two stars merge together violently,

but without actually going supernova.

Schaefer used the phrase merge first to describe the event.

People, maybe some of you, will see a new bright star flare into existence

when a white dwarf star merges with a more massive pier.

This is a unique system in our stellar catalogs.

There is no other white dwarf star observed to be in this kind of a close orbit with a more massive star.

This is a rare combination because large stars evolve faster than small stars,

and to get a system with a more evolved smaller star requires something remarkable,

such as two stars forming separately,

but getting gravitationally bound together later in their lives.

Over the past hundred years, observers have watched V. Sagittay and seen Nove associated with the explosion of built-up material

that flowed from the massive star onto the white dwarf.

But differently, material is streaming from the giant star onto the white dwarf,

and when the pile-up gets large enough, it explodes, and we see those explosions as repeating and cataclysmic explosions.

Over time, this system has gotten brighter and brighter in a way that can be explained as the two stars spiraling together.

By estimating the current separation and the rate the stars are moving together,

it's possible to set a go-boom date.

And that date is 2083. Give or take a decade or so.

When this happens, the star will go from just visible in a small telescope to as bright or brighter than serious.

Currently, the brightest star in the sky.

According to the press release, the end result of the merger will produce a single star with a degenerate white dwarf core,

a hydrogen burning layer, surrounded by a vast gas envelope, mostly of hydrogen.

We could talk more on this subject, but there is so much more news to cover,

so we're going to conclude here and work to get Brad Schafer to join us as a future guest here on the Daily Space.

On Monday, the test mission announced the discovery of a rocky Earth-sized planet in the habitable zone of an indoor star.

This is test's first such discovery, catalogued as T-O-1700D.

This world is one of three known in this system.

The team ran 20 atmospheric models to try and determine if the world could be habitable.

And for some of these models, the answer was, if you find Chicago habitable, you'd probably be fine there.

While follow-up observations with Spitzer made it possible to measure the world's size and mass,

it wasn't enough to actually measure the atmosphere.

And with the distance of 100 light years, it may not even be possible for the James Webb Space Telescope to figure out if this world may have life.

But, this looks like an Earth-masked rocky world in a habitable zone.

This is it, folks. We've found some place that is meteorologically going to be unlike anything we've ever experienced,

but geophysically, maybe as familiar as the world we walk on.

Test also announced the discovery of a planet orbiting two stars, such as the Planet Tatooine in the Star Wars series.

And they found that the excellently named Alpha Draconis is made of two stars that eclipse one another.

Also known as Thuban, this system has long been known to be two widely separated non-interacting stars.

It is actually one of the brightest binary systems we know of.

Somehow, however, no one had previously noticed that the stars periodically eclipsed one another.

The brightness is likely the reason.

Most detectors will get saturated looking at the system,

and it will be as effective at measuring its brightness as a symbol would be at measuring the volume of a bucket of water that is poured all at once.

Now we know that for about six hours in every 51.4, the system goes into a primary eclipse.

And here is the crazy factoid this leads to.

Thuban was once the pole star, which means that people navigated by the light of two suns that alternated for the primary role of true North.

There was so much news this week we could report.

But we're going to save most of it for later this week.

We'll me expect things to slow down a bit as folks work to recover from double AS, which ends Wednesday.

We do want to highlight one more release we're still not sure about.

A team of South Korean astronomers has done a new and careful analysis of the host galaxies of a type 1A Supernovae.

And has looked for trends in the relationship between the kinds of stars they have and the brightness of the Supernovae they produce.

It's long been recognized that there is some scatter in the brightness of these exploding systems.

And they find a correlation between the luminosity of the Supernovae and the stellar populations of their host galaxies.

This work, which is the result of nine years of detailed observations and analysis using the lost components, observatory and the 6.5 meter multi-maritaloscope,

seems to indicate that as the universe and its stellar populations have aged, the type 1A Supernovae produced have also changed.

This result, if true, is one of those things that will instantly turn over two decades of research.

Type 1A Supernovae are treated as standard candles that are assumed to have the same average brightness across all of time.

If they're actually changing in average brightness, then our most distant measurements of the universe are based on a bad assumption.

In their analysis, this team, which is led by Jungwook Lee, finds that dark energy is no longer needed to explain our universe's expansion.

They admit that extraordinary results require extraordinary evidence and that this work will need to be replicated.

If it is replicated, the biggest question in astronomy goes away as just an oops, we made a bad assumption that let us down a rabbit hole.

It means folks like Adam Rice, who got the Nobel Prize, have to ask themselves some really hard questions.

And we need to think about the justifications we have today for the telescopes we're building to explore dark energy in the future.

Telescopes like the W first mission.

It means we may be able to get around the problem of the Hubble constant looking different at different times by just eliminating dark energy from our equations.

And those equations would actually be way easier to work with.

But this is only if this paper is true.

This is just one publication, but it is by one team that is large, that is worked hard, and studied this for nine years.

And is publishing their paper in the astrophysical journal. Pamela, who wrote this, is concerned that the results aren't going to be treated to open consideration as readily as they would if they came from a team at Stanford, Princeton, or Yale.

They need to be considered however, and someone needs to replicate this to see if it holds up.

For now, this is the story we're going to be watching.

Because let's face it, dark energy makes no sense.

And this would be one hell of a graceful way to get ourselves back to a more comprehensible story of our universe.

And that rounds out our show for today.

Thank you for listening.

The daily space is produced by me, Susie Merv, and is a product of the Planetary Science Institute, a 501-C3 nonprofit dedicated to exploring our solar system and beyond.

We are here thanks to the generous contributions of people like you.

Want to become a supporter of the show?

Check us out at patreon.com slash cosmoquestax.

Each live episode of the daily space is archived on YouTube.

If you miss an episode on Twitch TV, you can find it later on youtube.com slash c slash cosmoquest.

These episodes are also edited and produced by me, Susie Merv.

We really wouldn't be here without you.

So thank you for all you do.

You're listening to the 365 Days of Astronomy Podcast.

Cool.

The 365 Days of Astronomy Podcast is produced by the Planetary Science Institute.

Audio post-production is by me, Richard Jerome.

Project management is by Aviva Yamani, and hosting is donated by libson.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 cosmoquest.x, 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 and space exploration,

we come closer to understanding the cosmos and our place within it.

Until next time, let the stars guide your curiosity.