- Exploding white dwarf stars are a type of supernova. Astronomers have found thousands of them so far.
- The upcoming new Rubin Observatory should find millions more, scientists say. It will scan the night sky faster than ever before.
- Astronomers can use these white dwarf supernovae to measure the expansion of the universe and how dark energy might influence it.
Using exploding white dwarfs to measure the universe
When the new Vera C. Rubin Observatory becomes operational later this year, it will begin to rapidly scan the night sky. One of its objectives is to search for Type Ia supernovae. Those are a type of supernova that occur in binary star systems (where two stars orbit one another) in which one of the stars is a white dwarf. Astronomers expect the telescope to find millions more of these exploding dying stars, researchers with Rubin Observatory said on January 22, 2025. Scientists can analyze the light from these supernovae to measure distances in the universe and the universe’s expansion rate. They can also better understand how dark energy affects that expansion.
The 2025 EarthSky lunar calendar makes a great gift. Get yours today!
Millions of exploding white dwarfs
Right now, the Vera C. Rubin Observatory is under construction on Cerro Pachón in Chile. Later this year, the construction should be complete and science operations should begin. The observatory will then begin its 10-year-long Legacy Survey of Space and Time. During that survey, astronomers expect Rubin to find millions of Type Ia supernovae. Those are a type of supernova where white dwarf stars explode. And they’re some of the most powerful and brightest known.
Astronomers have already found thousands of them, but the detections are fleeting. That’s where Rubin comes in. It will scan the sky every night for 10 years and cover the entire hemisphere every few nights. When it detects a new Type Ia supernova, it will immediately send an alert to astronomers. In fact, Rubin will produce about 20 terabytes of data and generate up to 10 million alerts every night.
Seven community software systems will be needed to manage the deluge of alerts. They will process the alerts and then pass them on to astronomers. The software systems will also merge Rubin data with other datasets. Then, they will use machine-learning to classify the supernovae according to their type, such as kilonovae, variable stars or Type Ia supernovae.
Scientist Anais Möller, a member of the Rubin/LSST Dark Energy Science Collaboration, said:
The large volume of data from Rubin will give us a sample of all kinds of Type Ia supernovae at a range of distances and in many different types of galaxies.
Artist’s visualization of a white dwarf star exploding as a Type Ia supernovae. The white dwarf sucks matter from its binary star companion. When it becomes heavier than a certain limit, it becomes unstable and explodes. Video via ESO.
Expansion of the universe and dark energy
Astronomers can use the detections of Type Ia supernovae to better measure the expansion of the universe. By analyzing their brightness and color, along with information about their host galaxies, scientists can calculate their distance and how much the universe expanded while their light was traveling to us. Once they have enough observations, astronomers can measure the expansion rate of the universe and determine whether it changes over time.
These measurements can also give astronomers a better idea of how dark energy influences the universe’s expansion. Möller said:
The universe expanding is like a rubber band being stretched. If dark energy is not constant, that would be like stretching the rubber band by different amounts at different points. I think in the next decade we will be able to constrain whether dark energy is constant or evolving with cosmic time. Rubin will allow us to do that with Type Ia supernovae.
Ultimately, Rubin will change how this kind of science is done in the future. As Möller noted:
Because of the large volumes of data, we can’t do science the same way we did before. Rubin is a generational shift. And our responsibility is developing the methods that will be used by the next generation.
Bottom line: The Rubin Observatory will find millions of exploding white dwarfs, or Type Ia supernovae. Astronomers can use them to measure the universe and dark energy.
Read more: A buddy for Betelgeuse? Does this mean no supernova?
Read more: See Supernova 1987A in a new light from Webb
The post Using exploding white dwarfs to measure the universe first appeared on EarthSky.
from EarthSky https://ift.tt/wbI92yU
- Exploding white dwarf stars are a type of supernova. Astronomers have found thousands of them so far.
- The upcoming new Rubin Observatory should find millions more, scientists say. It will scan the night sky faster than ever before.
- Astronomers can use these white dwarf supernovae to measure the expansion of the universe and how dark energy might influence it.
Using exploding white dwarfs to measure the universe
When the new Vera C. Rubin Observatory becomes operational later this year, it will begin to rapidly scan the night sky. One of its objectives is to search for Type Ia supernovae. Those are a type of supernova that occur in binary star systems (where two stars orbit one another) in which one of the stars is a white dwarf. Astronomers expect the telescope to find millions more of these exploding dying stars, researchers with Rubin Observatory said on January 22, 2025. Scientists can analyze the light from these supernovae to measure distances in the universe and the universe’s expansion rate. They can also better understand how dark energy affects that expansion.
The 2025 EarthSky lunar calendar makes a great gift. Get yours today!
Millions of exploding white dwarfs
Right now, the Vera C. Rubin Observatory is under construction on Cerro Pachón in Chile. Later this year, the construction should be complete and science operations should begin. The observatory will then begin its 10-year-long Legacy Survey of Space and Time. During that survey, astronomers expect Rubin to find millions of Type Ia supernovae. Those are a type of supernova where white dwarf stars explode. And they’re some of the most powerful and brightest known.
Astronomers have already found thousands of them, but the detections are fleeting. That’s where Rubin comes in. It will scan the sky every night for 10 years and cover the entire hemisphere every few nights. When it detects a new Type Ia supernova, it will immediately send an alert to astronomers. In fact, Rubin will produce about 20 terabytes of data and generate up to 10 million alerts every night.
Seven community software systems will be needed to manage the deluge of alerts. They will process the alerts and then pass them on to astronomers. The software systems will also merge Rubin data with other datasets. Then, they will use machine-learning to classify the supernovae according to their type, such as kilonovae, variable stars or Type Ia supernovae.
Scientist Anais Möller, a member of the Rubin/LSST Dark Energy Science Collaboration, said:
The large volume of data from Rubin will give us a sample of all kinds of Type Ia supernovae at a range of distances and in many different types of galaxies.
Artist’s visualization of a white dwarf star exploding as a Type Ia supernovae. The white dwarf sucks matter from its binary star companion. When it becomes heavier than a certain limit, it becomes unstable and explodes. Video via ESO.
Expansion of the universe and dark energy
Astronomers can use the detections of Type Ia supernovae to better measure the expansion of the universe. By analyzing their brightness and color, along with information about their host galaxies, scientists can calculate their distance and how much the universe expanded while their light was traveling to us. Once they have enough observations, astronomers can measure the expansion rate of the universe and determine whether it changes over time.
These measurements can also give astronomers a better idea of how dark energy influences the universe’s expansion. Möller said:
The universe expanding is like a rubber band being stretched. If dark energy is not constant, that would be like stretching the rubber band by different amounts at different points. I think in the next decade we will be able to constrain whether dark energy is constant or evolving with cosmic time. Rubin will allow us to do that with Type Ia supernovae.
Ultimately, Rubin will change how this kind of science is done in the future. As Möller noted:
Because of the large volumes of data, we can’t do science the same way we did before. Rubin is a generational shift. And our responsibility is developing the methods that will be used by the next generation.
Bottom line: The Rubin Observatory will find millions of exploding white dwarfs, or Type Ia supernovae. Astronomers can use them to measure the universe and dark energy.
Read more: A buddy for Betelgeuse? Does this mean no supernova?
Read more: See Supernova 1987A in a new light from Webb
The post Using exploding white dwarfs to measure the universe first appeared on EarthSky.
from EarthSky https://ift.tt/wbI92yU
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