Normal Stars & Star Clusters

R Aquarii, All Wavelengths

Credit: X-ray: NASA/CXC/SAO/R. Montez et al.; Optical: Data: NASA/ESA/STScI, Enhanced processing by Judy Schmidt (CC BY-NC-SA). X-ray/Optical composite processing by CXC/N. Wolk & K.Arcand; Sonification: NASA/CXC/SAO/K.Arcand, SYSTEM Sounds (M. Russo, A. Santaguida)

The system called R Aquarii unfolds dramatically through the eyes of NASA’s Chandra X-ray Observatory (purple) and Hubble Space Telescope (red and blue). The spectacular structures outlined in the Hubble data are old notes, or in other words, evidence from outbursts generated by a pair of stars buried at the center of the image. X-rays from Chandra reveal how a jet from one of these stars — a cool stellar ember known as a white dwarf — is banging into the material surrounding it. This high-powered flow creates shock waves, similar to sonic booms from planes that move faster than the speed of sound. The other player with the white dwarf in this interstellar duet is a red giant star. As they orbit each other, the white dwarf pulls material from the red giant onto its surface. Over time, enough of this material accumulates and triggers an explosion. Astronomers have seen such outbursts over recent decades and this dynamic chorus will likely go on for millennia to come.

Credit: NASA/CXC/Leisa Townsley

When Dr. Leisa Townsley passed away this summer, the scientific community lost a brilliant researcher, teacher, and mentor. She was all of those things, but we wanted to feature some of the pivotal and critical ways that she helped the Chandra X-ray Observatory, specifically our Communications and Public Engagement work.

Chandra was launched into space in 1999 and with the beginning of its successful operations, a new era in high-energy astrophysics was born. For certain deep space objects that emitted enough X-ray photons, Chandra brought, for the first time, the ability to create richly detailed, high-resolution images. These X-ray images, however, were different in many ways from the images of its previously-launched sister Great Observatory, the Hubble Space Telescope.

Establishing a visual identity for Chandra, both on its own and in collaboration with other telescopes that study different kinds of light, including Hubble, was no small challenge. Our Chandra group was responsible for finding the best way to show X-ray data, which often looks completely different from optical data. Would traditional techniques used for visible light data be suitable to process X-ray data? Would new processes and tactics need to be developed to make X-ray data more accessible, easier to understand and process?

NGC 3293
Credit: X-ray: NASA/CXC/Penn State Univ./K. Getman et al.; Infrared: ESA/NASA JPL-Caltech/Herschel Space Observatory/JPL/IPAC; NASA JPL-Caltech/SSC/Spitzer Space Telescope; Optical: MPG/ESO/G. Beccari;

Astronomers have made the most extensive study yet of how magnetically active stars are when they are young. This gives scientists a window into how X-rays from stars like the Sun, but billions of years younger, could partially or completely evaporate the atmospheres of planets orbiting them.

Many stars begin their lives in “open clusters,” loosely packed groups of stars with up to a few thousand members, all formed roughly at the same time. This makes open clusters valuable for astronomers investigating the evolution of stars and planets, because they allow the study of many stars of similar ages forged in the same environment.

A team of astronomers led by Konstantin Getman of Penn State University studied a sample of over 6,000 stars in 10 different open clusters with ages between 7 million and 25 million years. One of the goals of this study was to learn how the magnetic activity levels of stars like our Sun change during the first tens of millions of years after they form. Getman and his colleagues used NASA’s Chandra X-ray Observatory for this study because stars that have more activity linked to magnetic fields are brighter in X-rays.

RCW 36
Credit: X-ray: NASA/CXC/Ames Research Center/L. Bonne et al.; Infrared: ESA/NASA.JPL-Caltech/Herschel Space Observatory/JPL/IPAC

Many factors can limit the size of a group, including external ones that members have no control over. Astronomers have found that groups of stars in certain environments, however, can regulate themselves.

A new study has revealed stars in a cluster having “self-control,” meaning that they allow only a limited number of stars to grow before the biggest and brightest members expel most of the gas from the system. This process should drastically slow down the birth of new stars, which would better align with astronomers’ predictions for how quickly stars form in clusters.

This study combines data from several telescopes including NASA's Chandra X-ray Observatory, NASA's now-retired Stratospheric Observatory for Infrared Astronomy (SOFIA), the APEX (the Atacama Pathfinder EXperiment) telescope, and ESA’s (European Space Agency’s) retired Herschel telescope.

Hot Jupiters
Credit: Illustration: NASA/CXC/M.Weiss. X-ray: NASA/CXC/Potsdam Univ./N. Ilic et al.

An artist’s illustration shows a gas giant planet (lower right) closely orbiting its host star (left), with another star in the distance (upper right). The two stars are themselves in orbit with each other. As explained in our latest press release, a team of scientists used NASA’s Chandra X-ray Observatory and ESA’s XMM-Newton to test whether such exoplanets (known as “hot Jupiters”) affect their host star in comparison to the star that does not have one. The results show that these exoplanets can make their host star act younger than it is by causing the star to spin more quickly than it would without such a planet.

The double-star (or “binary”) system in the illustration is one of dozens that astronomers studied using Chandra and XMM-Newton to look for the effects of hot Jupiters on their host stars. A hot Jupiter can potentially influence its host star by tidal forces, causing the star to spin more quickly than if it did not have such a planet. This more rapid rotation can make the host star more active and produce more X-rays, making it appear younger than it really is.

Zeta Ophiuchi
Credit: X-ray: NASA/CXC/Dublin Inst. Advanced Studies/S. Green et al.; Infrared: NASA/JPL/Spitzer

Zeta Ophiuchi is a star with a complicated past, having likely been ejected from its birthplace by a powerful stellar explosion. A new look by NASA's Chandra X-ray Observatory helps tell more of the story of this runaway star.

Located about 440 light-years from Earth, Zeta Ophiuchi is a hot star that is 20 times more massive than the Sun. Previous observations have provided evidence that Zeta Ophiuchi was once in close orbit with another star, before being ejected at about 100,000 miles per hour when this companion was destroyed in a supernova explosion over a million years ago. Previously released infrared data from NASA's now-retired Spitzer Space Telescope, seen in this new composite image, reveals a spectacular shock wave (red and green) that was formed by matter blowing away from the star's surface and slamming into gas in its path. Data from Chandra shows a bubble of X-ray emission (blue) located around the star, produced by gas that has been heated by the effects of the shock wave to tens of millions of degrees.