Connect with us

Twinkle, twinkle little star, I wonder just how old you are.

It isn’t an easy question to answer. Stars are notoriously difficult to age. We know the age of the Sun because we happen to live on one of its orbiting rocks, and we know very well how old the rock is. Without that information, things become a bit more fuzzy. But that could change thanks to a new study.

We do know a few broad rules about determining the age of a star. For example, generally the higher the metallicity of a star the younger it is. And main sequence stars like the Sun tend to get hotter as they age, so if two stars have the same mass and composition, the hotter of the two is likely the older. But by themselves, these general rules aren’t enough to get a precise age determination. For that, we typically look at clusters of stars.

Star clusters such as open clusters and globular clusters generally form within a single molecular cloud, and they do so around the same time. When you look at the stars in a cluster you know they are all around the same age. Astronomers can use this fact to get a good age for star clusters. Individually there will be variations in things like metallicity and temperature, but statistically, the average age determination is a good measure of the cluster’s age.

But one thing that has been noticed is that among star clusters, older clusters have stars that rotate more slowly than stars in young clusters. This suggests that a star’s rotation rate slows down as it ages. This would be a great way to determine stellar age because many stars have starspots, which we can use to measure rotation pretty easily. There are just two problems. The first is that within a cluster stars can be gravitationally bound, and this interaction might be driving the slowdown. If so, then individual stars wouldn’t experience the same rotational decay. The second is that the metallicity of a star affects its density and temperature, so metallicity could have a significant effect on the slowdown rate.

rotation 965x1024 2
Star cluster age (lines) vs binary star age (circles/diamonds). Credit: Gruner, et al

Still, the technique would be so useful that a team wanted to explore it further. They looked at 300 wide binary stars. These are binary stars with orbital distances large enough that their rotations are independent of each other. And since binary systems form all at once, the team could be confident that binary pairs were the same age.

The team then applied the cluster method of using temperature and rotation rate to determine the age of each star in a pair. They found that the ages of binary pairs matched using this method. And with 300 samples to work with, they are confident the method works. The team also found the approach worked regardless of the metallicity of the stars. So while metallicity might have a small effect on stellar age, the rotation approach works all the same.

From this work, astronomers can feel confident in using rotation as an age measure regardless of whether a star is single, binary, or part of a cluster. This is great news. Telescope satellites such as Gaia and the upcoming PLATO mission have the search for exoplanets as part of their mission. The same method used to find the dip in stellar brightness as an exoplanet transits can also be used to measure the rotational rate of a star through starspots. In time could know the age of billions of stars as well as their motion and whether they have planets.

Reference: Gruner, D., S. A. Barnes, and K. A. Janes. “Wide binaries demonstrate the consistency of rotational evolution between open cluster and field stars.” Astronomy & Astrophysics 675 (2023): A180.

The post Astronomers Have a New Trick to Work out the Age of Stars appeared first on Universe Today.

Did you miss our previous article…
https://mansbrand.com/olympus-could-have-been-a-giant-volcanic-island-in-an-ancient-martian-ocean/

Total
0
Shares
Share 0
Tweet 0
Pin it 0
Share 0
Related Topics:
Continue Reading

Frontier Adventure

Fly Slowly Through Enceladus’ Plumes to Detect Life

enceladusfountains med.thumbnail 2 jpg

Enceladus is blasting water into space from the jets at its southern pole. This makes it the ideal place to send a dedicated mission, flying the spacecraft through the plumes with life-detection instruments s. A new study suggests that a spacecraft must proceed carefully through the plumes, keeping its speed below 4.2 km/second (2,236 miles per hour). Using a specialized, custom-built aerosol impact spectrometer at these speeds will allow fragile amino acids to be captured by the spacecraft’s sample collector. Any faster, they’ll shatter, providing inclusive results.

One of the biggest surprises of the 20-year Cassini mission to the Saturn system was the discovery of the active geysers at Enceladus. At only about 500 km (310 miles) in diameter, the ice-covered Enceladus should be too small and too far from the Sun to be active. Instead, this little moon is one of the most geologically dynamic objects in the Solar System.

enceladusfountains_med.thumbnail.jpg
Geysers spew from Enceladus in this image from the Cassini spacecraft. Credit: NASA/Cassini mission.

Cassini’s stunning backlit images of this moon show plumes erupting in Yellowstone-like geysers, emanating from tiger-stripe-shaped fractures in the moon’s surface. The discovery of the geysers took on more importance when Cassini later determined the plumes contained water ice and organics. Since life as we know it relies on water and a source of energy, this small but energetic moon has been added to the short list of possible places for life in our Solar System.

During three of Cassini’s passes of Enceladus in 2008 and 2009, the spacecraft’s Cosmic Dust Analyser measured the composition of freshly ejected plume grains. The icy particles hit the detector target at speeds of 6.5–17.5 km/s, and vaporized instantly. While electrical fields inside the instrument were able to separate the various constituents of the resulting impact cloud for analysis, for a future mission, scientists would like to measure the particles in the plumes without completely vaporizing them.

Back in 2012, researchers from the University of California San Diego started working on a custom-built unique aerosol impact spectrometer, designed to study collision dynamics of single aerosols and particles at high velocities. Although it wasn’t built specifically to study ice grain impacts, it turns out this instrument might be exactly what planetary scientists are looking for to use at Enceladus, or even at Jupiter’s moon Europa, where there is growing evidence of active plumes of water vapor erupting from its surface.

Robert Continetti’s one-of-a-kind aerosol impact spectrometer was used in this experiment. Ice grains impact the microchannel plate detector (far right) at hypervelocity speeds, which can then be characterized in-situ.

Continetti and several colleague have now tested the device in a laboratory, showing that amino acids transported in ice plumes — like at Enceladus — can survive impact speeds of up to 4.2 km/s. Their research is published in The Proceedings of the National Academy of Sciences (PNAS).

“This apparatus is the only one of its kind in the world that can select single particles and accelerate or decelerate them to chosen final velocities,” said Robert Continetti, a professor from UC San Diego, in a press release. “From several micron diameters down to hundreds of nanometers, in a variety of materials, we’re able to examine particle behavior, such as how they scatter or how their structures change upon impact.”

From Cassini’s measurements, scientists estimate the ice plumes at Enceladus blast out at approximately .4 km/s (800 miles per hour). A spacecraft would have to fly at the right speeds to make sure the particles could be captured intact.

opo1633a 1024x1024 1 jpg
This composite image shows suspected plumes of water vapour erupting at the 7 o’clock position off the limb of Jupiter’s moon Europa. The plumes, photographed by Hubble’s Imaging
Did you miss our previous article…
https://mansbrand.com/the-international-space-station-celebrates-25-years-in-space/

Continue Reading

Frontier Adventure

The International Space Station Celebrates 25 Years in Space

DrRDzDDX0AEQSxB 750 jpg

NASA recently celebrated the 25th anniversary of the International Space Station (ISS) with a space-to-Earth call between the 7-person Expedition 70 crew and outgoing NASA Associate Administrator, Bob Cabana, and ISS Program Manager, Joel Montalbano. On December 6, 1998, the U.S.-built Unity module and the Russian-built Zarya module were mated in the Space Shuttle Endeavour cargo bay, as Endeavour was responsible for launching Unity into orbit that same day, with Zarya having waited in orbit after being launched on November 20 from Kazakhstan.

“I cannot believe it was 25 years ago today that we grappled Zarya and joined it with the Unity node,” said Cabana during the call from NASA Headquarters in Washington, D.C. “Absolutely amazing.”

While this milestone marks 25 years since the first two ISS modules were attached, it would be another two years until the ISS had a crew, Expedition 1, which arrived at the ISS in November 2000 and stayed until March 2001, beginning an uninterrupted human presence on the ISS that continues today. During the two-year period between the first mating and Expedition 1, the Russian-built Zvedza module was attached to the Unity and Zarya modules on July 26, 2000, after launching from Kazakhstan two weeks earlier. Assembly of the large modules of the ISS would continue until 2021 when the Roscosmos-funded Nauka module was attached in July 2021.

Now in its final configuration, the ISS is approximately the size of an American gridiron football field consisting of 8 solar arrays that provide the station’s power while maintaining an average altitude of 400 kilometers (250 miles). Its massive size consists of a pressurized module length along the major axis of 67 meters (218 feet), a truss (primary body) length of 94 meters (310 feet), a solar array length (measured along the truss) of 73 meters (239 feet), and a total mass of 419,725 kilograms (925,335 pounds).

DrRDzDDX0AEQSxB 750 1 jpg
Artist rendition of the ISS compared to an American gridiron football field. (Credit: NASA)
The station pictured from the SpaceX Crew Dragon 5 cropped 750 jpg
Image of the ISS taken by SpaceX Crew-2 mission on November 8, 2021 after it successfully undocked from the ISS Harmony module. (Credit: NASA)

Ever since the 3-person Expedition 1 crew first took command of the ISS, a total of 273 individuals from 21 countries have visited the orbiting laboratory and have been comprised of trained astronauts and private visitors. From most visitors to least, the following visitor countries include the United States, Russia, Japan, Canada, Italy, France, Germany, Saudi Arabia, United Arab Emirates, Belgium, Brazil, Denmark, Great Britain, Israel, Kazakhstan, Malaysia, Netherlands, South Africa, South Korea, Spain, and Sweden.

“One of my favorite aspects of the International Space Station is the international part of it,” said NASA Astronaut and Expedition 70 Flight Engineer, Jasmin Moghbeli, during the call. “We each bring our unique perspectives, not just from our different nationalities, but also our different backgrounds. I think we’re definitely strengthened by the international partnership. It’s just like gaining redundancy when you have multiple partners working together. It’s stronger and more resilient to any sort of problems or obstacles that come our way and so it definitely makes us stronger. And I think that’s why we have had the International Space Station up here for 25 years now.”

photo 7 1 750 1

Continue Reading

Frontier Adventure

Starship | Second Flight Test

hqdefault 2

hqdefault 3

On November 18, 2023, Starship successfully lifted off at 7:02 a.m. CT from Starbase on its second integrated flight test.

While it didn’t happen in a lab or on a test stand, it was absolutely a test. What we did with this second flight will provide invaluable data to continue rapidly developing Starship.

The test achieved a number of major milestones, helping us improve Starship’s reliability as SpaceX seeks to make life multiplanetary. The team at Starbase is already working final preparations on the vehicles slated for use in Starship’s third flight test.

Congratulations to the entire SpaceX team on an exciting second flight test of Starship!

Follow us on X.com/SpaceX for continued updates on Starship’s progress

Did you miss our previous article…
https://mansbrand.com/for-its-final-trick-chandrayaan-3-brings-its-propulsion-module-to-earth-orbit/

Continue Reading

Trending