sun like star

Twelve stars have received X-ray passports. Now, for each of them, we know the exact radiation dose received by a planet in the habitable zone, the region where liquid water is possible.

A telescope stares at a star for many nights in a row. Somewhere in the stream of light hides a tiny dip in brightness — an Earth-sized planet briefly blocking part of the star. Such a dip lasts a few hours and repeats once a year or less. Catching it is like hearing a single quiet click in a noisy hall.

Two stars, AF Lep A and ε Indi A, have become the focus of close attention. Using the GHOST spectrograph on the Gemini telescope, astronomers split their light into colors and, from absorption lines, determined how much carbon, oxygen, sulfur, and thirteen other elements are in the stars' atmospheres.

Cosmic rays aren't rays in the usual sense: they're fast particles bombarding Earth from all directions. Mostly they're protons and atomic nuclei. Their energies vary widely, from modest to fantastically huge. When such a particle heads our way and the Moon or Sun gets in its path, it gets absorbed.

Every star is a living archive, and its spectrum a multilayered manuscript. Over billions of years, the history of the galaxy is written into it: the galactic chemical evolution of the Milky Way leaves a smooth trace in elemental abundances.

For years, the Sun teased astrophysicists. In its atmosphere, refractory elements, like spices in a basic recipe, were slightly less abundant than in nearly identical twin stars. Suspicion arose: could our star be modest, skipping the planetary "dessert" that others devour with gusto?

A planet glides across a star's disk, and for a moment becomes a flashlight. It blocks a tiny patch of surface, revealing details that otherwise escape our view. That's exactly how astronomers peered into the dark spots on V1298 Tauri, a young twin of our Sun. They were aided by the James Webb Space Telescope JWST and three giant planets in orbit.

Tiny invisible bullets pass straight through the Sun, barely noticing its matter. These are axions — hypothetical particles so light and elusive that they are often compared to ghosts.

Two lamps in a shop window: one glows with a cool, bluish light, the other a bit warmer and yellower. That's roughly how the two types of supernovae, Ib and Ic, look when astronomers view them through a telescope.

A guitar string only sounds at certain notes, when pressed at the frets. So it is with the gas-dust disk around a young star: it's shot through with standing waves, but only chosen oscillations survive. Where the wave crests, cosmic dust and hydrogen collect, and later exoplanets are born.

Hot massive stars are the kitchens of the Universe, where heavy elements are cooked up. They end their lives in supernova explosions. To understand their recipe, astronomers use spectroscopy — the analysis of the rainbow band of light passed through a prism. Previously, deciphering such a 'menu' took hours.

The Sun is not a perfectly steady lightbulb. Its brightness quivers slightly: it dims a bit, then brightens. For Earth's climate, even slow variations stretched over thousands and millions of years matter. They could have left their mark in the geological record of the last 540 million years. Astronomer [scientist:A. M.

GJ 504, a star almost the same age as our Sun, is spinning with remarkable vigor: it completes a full rotation in just 3.4 Earth days, while actively emitting X-rays. For comparison, typical stars of the Sun's age rotate much more slowly, as if they've lost their youthful energy. GJ 504, however, behaves like a figure skater who has received a powerful push and launched into a rapid spin.

NASA's TESS space telescope monitors thousands of stars, catching the moment when a planet crosses its star's disk — the star's light dims slightly. That's how astronomers spotted two planets orbiting stars similar to our Sun. One, TOI-883 b, completes an orbit in ten days; the other, TOI-899 b, takes nearly thirteen.

Light from the galaxy PAN-z14-1 began its journey when the universe was 400 million years old — a cosmic infancy. The expansion of space made it travel to us for nearly 13.5 billion years.

Some superluminous supernovae show a bright oxygen imprint in their light and expand rapidly, while others do not. It seemed like different phenomena. But supernova PTF12dam broke the rules: as its brightness grew, its oxygen signature changed, shifting from one type to another.

Sun-like stars rarely spin alone. Many of them dance with invisible partners — brown dwarfs: objects bigger than planets but too lightweight for steady stellar burning. In their cores, hydrogen fusion flickers, only to fade fast, never matching the stability of the Sun.

Life began with molecules akin to natural sunscreen — based on carbon, they soaked up the mild ultraviolet of the young Sun and turned it into heat. This way of dissipating energy wasn’t just heating: it made molecules self-organize, like chefs kneading structured dough out of a chaos of ingredients. But ultraviolet is a finicky tool.

In August 2024, the MIRI coronagraph on the James Webb Space Telescope stared at Alpha Centauri A, the nearest Sun-like star to our Sun. At 1.5 arcseconds from the star, a point source, S1, blinked into view. Flux: 3.5 mJy, contrast: 5.5×10⁻⁵. Four to six sigma. A lighthouse flashing in the fog.