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Repairing a broken parent-adult child relationship is possible if both sides approach it earnestly and honestly

The experimental fusion reactor sustained temperatures of 180 million degrees Fahrenheit for a record-breaking 48 seconds.

ESA accelerates the race towards clean energy from space

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Video: 00:02:35

Meet Hera, our very own asteroid detective. Together with two CubeSats – Milani the rock decoder and Juventas the radar visionary – Hera is off on an adventure to explore Didymos, a double asteroid system that is typical of the thousands that pose an impact risk to planet Earth.

In September 2022 NASA’s DART spacecraft tested if it was possible to divert an asteroid by giving it a shove – and found out that it was! Important knowledge, should we wish to avoid going the same way as the dinosaurs. Astronomers can observe from afar how the smaller asteroid’s orbit has shifted since DART’s impact, but there is still a missing piece of the puzzle if we want to fully understand how ‘kinetic impacting’ works in practice. Suitable for kids and adults alike, this episode of ‘The Incredible Adventures of Hera’ explains why ESA’s asteroid detective and its CubeSat assistants need to get up close and personal to shine light on this cosmic mystery.

Watch the other episodes of The Incredible Adventures of the Hera Mission

A star in the constellation Norma appears to have been created when two stars merged.

The post See What Happens When Stars Collide appeared first on Sky & Telescope.

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The experimental fusion reactor sustained temperatures of 180 million degrees Fahrenheit for a record-breaking 48 seconds.

NASA's Dana Weigel has held leadership positions at the agency for 20 years. Now leading the ISS program, she highlighted the outpost's increasingly commercial focus.

A three-legged robot named SpaceHopper could help combat challenges of exploring low-gravity environments, such as asteroids or moons.

An international research team led by the University of Vienna has made a major breakthrough. In a study recently published in Nature Astronomy, they describe how they conducted the first direct measurements of stellar wind in three Sun-like star systems. Using X-ray emission data obtained by the ESA’s X-ray Multi-Mirror-Newton (XMM-Newton) of these stars’ “astrospheres,” they measured the mass loss rate of these stars via stellar winds. The study of how stars and planets co-evolve could assist in the search for life while also helping astronomers predict the future evolution of our Solar System.

The research was led by Kristina G. Kislyakova, a Senior Scientist with the Department of Astrophysics at the University of Vienna, the deputy head of the Star and Planet Formation group, and the lead coordinator of the ERASMUS+ program. She was joined by other astrophysicists from the University of Vienna, the Laboratoire Atmosphères, Milieux, Observations Spatiales (LAMOS) at the Sorbonne University, the University of Leicester, and the Johns Hopkins University Applied Physics Laboratory (JHUAPL).

Astrospheres are the analogs of our Solar System’s heliosphere, the outermost atmospheric layer of our Sun, composed of hot plasma pushed by solar winds into the interstellar medium (ISM). These winds drive many processes that cause planetary atmospheres to be lost to space (aka. atmospheric mass loss). Assuming a planet’s atmosphere is regularly replenished and/or has a protective magnetosphere, these winds can be the deciding factor between a planet becoming habitable or a lifeless ball of rock.

Logarithmic scale of the Solar System, Heliosphere, and Interstellar Medium (ISM). Credit: NASA-JPL

While stellar winds mainly comprise protons, electrons, and alpha particles, they also contain trace amounts of heavy ions and atomic nuclei, such as carbon, nitrogen, oxygen, silicon, and even iron. Despite their importance to stellar and planetary evolution, the winds of Sun-like stars are notoriously difficult to constrain. However, these heavier ions are known to capture electrons from neutral hydrogen that permeates the ISM, resulting in X-ray emissions. Using data from the XXM-Newton mission, Kislyakova and her team detected these emissions from other stars.

These were 70 Ophiuchi, Epsilon Eridani, and 61 Cygni, three main sequence Sun-like stars located 16.6, 10.475, and 11.4 light-years from Earth (respectively). Whereas 70 Ophiuchi and 61 Cygni are binary systems of two K-type (orange dwarf) stars, Epsilon Eridani is a single K-type star. By observing the spectral lines of oxygen ions, they could directly quantify the total mass of stellar wind emitted by all three stars. For the three stars surveyed, they estimated the mass loss rates to be 66.5±11.1, 15.6±4.4, and 9.6±4.1 times the solar mass loss rate, respectively.

In short, this means that the winds from these stars are much stronger than our Sun’s, which could result from the stronger magnetic activity of these stars. As Kislyakova related in a University of Vienna news release:

“In the solar system, solar wind charge exchange emission has been observed from planets, comets, and the heliosphere and provides a natural laboratory to study the solar wind’s composition. Observing this emission from distant stars is much more tricky due to the faintness of the signal. In addition to that, the distance to the stars makes it very difficult to disentangle the signal emitted by the astrosphere from the actual X-ray emission of the star itself, part of which is “spread” over the field-of-view of the telescope due to instrumental effects.”

XMM-Newton X-ray image of the star 70 Ophiuchi (left) and the X-ray emission from the region (“Annulus”) surrounding the star represented in a spectrum over the energy of the X-ray photons (right). Credit: C: Kislyakova et al. (2024)

For their study, Kislyakova and her team also developed a new algorithm to disentangle the contributions made by the stars and their astrospheres to the emission spectra. This allowed them to detect charge exchange signals from the stellar wind oxygen ions and the neutral hydrogen in the surrounding ISM. This constitutes the first time X-ray charge exchange emissions from the extrasolar astrospheres have been directly detected. Moreover, the mass loss rate estimates they derived could be used by astronomers as a benchmark for stellar wind models, expanding on what little observational evidence there is for the winds of Sun-like stars. As co-author Manuel Güdel, also of the University of Vienna, indicated:

“There have been world-wide efforts over three decades to substantiate the presence of winds around Sun-like stars and measure their strengths, but so far only indirect evidence based on their secondary effects on the star or its environment alluded to the existence of such winds; our group previously tried to detect radio emission from the winds but could only place upper limits to the wind strengths while not detecting the winds themselves. Our new X-ray based results pave the way to finding and even imaging these winds directly and studying their interactions with surrounding planets.”

In the future, this method of direct detection of stellar winds will be facilitated by next-generation missions like the European Athena mission. This mission will include a high-resolution X-ray Integral Field Unit (X-IFU) spectrometer, which Athena will use to resolve the finer structure and ratio of faint emission lines that are difficult to distinguish using XMM-Newton’s instruments. This will provide a more detailed picture of the stellar winds and astrospheres of distant stars, helping astronomers constrain their potential habitability while also improving solar evolution models.

Further Reading: University of Vienna, Nature Astronomy

The post Stellar Winds Coming From Other Stars Measured for the First Time appeared first on Universe Today.