The #DailySpace brings you the universe at 10am PST / 1pm EST / 5pm GMT on twitch.tv/CosmoQuestX. Today’s #spacenews includes the following stories:

When we talk about the Zwicky Transient Factory, we are normally talking about supernovae, asteroids, and other objects that are of life and death interest to our Earth. This isn’t one of those stories. Instead, it is the tale of two perfectly normal white dwarf stars that are in a little tiny orbit that is getting smaller by the day.

Discovered with the Zwicky Transient Factory and observed in detail with the Kitt Peak 2.1 meter telescope, this system, catalogued ZTF J1530+5027, this system could fit inside of Saturn. The stars 20% and 60% the mass of the sun, and the more massive has a smaller diameter that makes it just a bit bigger than Earth. The less massive is less compressed and appears physically bigger and significantly fainter. This difference in brightness is key. These stars are aligned so that they pass in front of each other from our viewpoint here on earth, and every 6.91 minutes, astronomers see that larger fainter less massive star block the light of the brighter star.

While just plain cool, this system is also of great scientific interest because these two dense stars are generating gravitational waves that will be detectable to the LISA mission when it launches in 2034. This system is radiating away gravitational energy and as the stars creep closer together at a rate of 26 cm/day. It’s low frequency gravitational paves should be near the the peak in LISA’s sensitivity, at 4.8 mHz. 

Today is a day of rare science sites, from one of the rare sources of gravitational waves from dead stars we jump to the rare sites of star birth.

In a new study from the NAOJ, astronomers use the Nobeyama Radio Observatory to probe the density of gas in our Milky Way galaxy. Looking around, they sky is filled with stars, but we know our galaxy is only producing a few new stars a year. To understand why, we need need to use radio galaxies to probe the gas density. The Japanese team behind this project showed that only 3% of the total gas is dense enough to form stars. So, yes, there is gas everywhere, but unless something smashes it into much denser distributions, we’re looking at limited star formation as the norm.

Speaking of gas, we’re going to close out today’s episode with the case of the missing matter and how it was found using South Africa’s MeerKAT radio telescopes.

The distorted galaxy NGC 1316 appears in optical images to be the result of a recent galactic collision. These conclusion is supported by it’s bright radio emission, which makes in the fourth brightest radio source in the sky and gives it the title Fornax A. This radio emission hints at star formation and an active black hole, both generated by gas getting driven into the center of the system. The thing is, otherwise this galaxy appears to have a much lower gas content then would be expected.

The new study, which maps gas outside the main body of the galaxy, shows that gas was also torn out of the merging system, creating two otherwise almost invisible arms of material. I say almost because these arms are also populated by stars that were similarly pulled out during the merger event. When all the torn out material is added up, there is enough stuff to build a normal galaxy pair.

This is just a nice case of observationally sweeping together all the debris scattered about in a collision and putting them together to see if a complete galaxy can be accounted for. This work shows MeerKATs potential to do slow and steady and detailed work into measuring our skies. And the cool thing is, this work is only a precursor to the Square Kilometer Array and the best is yet to come.

Join us tomorrow for more Daily Space news – and keep mapping Bennu!