In the vast cosmic theater, blue subdwarfs shine like silent witnesses to the complex stellar evolution. These compact stars represent an astonishingly rare and fascinating stage in the life of stars, particularly moderate to low mass stars. Their emergence, inscribed in an advanced process of stellar formation, raises many questions about the mechanisms governing the … Read more
Variable red giants represent a fascinating class of stars whose light variability intrigues both astrophysicists and astronomy enthusiasts. These evolved stars, gigantic in size, undergo stellar pulsations that periodically modify their brightness and influence their internal dynamics. The complexity of these pulsations offers direct insight into the internal structure of stars and opens major perspectives … Read more
Blue hypergiants represent the apex of mass and brightness in the stellar hierarchy. These rare and impressive objects dominate their galactic environment with exceptional energy and power. They are the stage for extreme phenomena related to nuclear fusion and represent a crucial step in understanding cosmic dynamics as well as the formation of stars in … Read more
Brown dwarfs intrigue and captivate contemporary astronomers, gradually redirecting our gaze towards these singular celestial bodies whose nature still eludes a rigid classification. These substellar objects intercalate between the gigantic gas giants like Jupiter and the cold stars of low mass, proving to be both luminous and tenuous, massive yet incapable of sustaining classical nuclear … Read more
In the vast universe, measuring astronomical distances has been a major challenge since the beginnings of astrophysics. The variable stars known as cepheids have become fundamental keys for this task, acting as standard candles that allow us to estimate cosmic distances with precision. Their discovery and understanding have revolutionized our ability to map the universe, … Read more
IN BRIEF Light spectra: Analysis of the light emitted by stars. Decomposition of white light via a prism or a grating. Absorption spectrum: Presence of dark lines, indicating chemical elements. Hydrogen: Identification by its specific emission lines. Visible colors: Observations ranging from violet to red. Emission lines: Allow identification of elements present in stars. Importance … Read more
IN BRIEF Giant gas planets: Jupiter and Saturn, formed nearly 5 billion years ago. Recent discovery of wandering double giant planets in the Orion nebula. Observation of planetary birth through gravitational collapse. Mysteries surrounding the formation and atmospheres of gas giants. Effects of atmospheric phenomena on Jupiter, including hurricanes and clouds. New theoretical models proposed … Read more
The quest for worlds suitable for life extends far beyond the traditional boundaries defined by the classic habitable zone. The study of extensive circumstellar habitable zones is revolutionizing our understanding of cosmic environments capable of supporting life. These zones correspond to orbital regions around stars where liquid water can exist and are now evaluated with … Read more
Ultra-precise spatial photometry represents a major advancement in the precise study of light coming from celestial objects. This discipline, once limited to simple visual measurements, has transformed thanks to the integration of sophisticated space technologies and advanced optical instrumentation methods, offering an unprecedented ability to record the light variations of stars and other celestial objects. … Read more
In short, stellar occultations prove to be incredibly effective tools at the service of modern astronomy. By temporarily masking a star with a celestial body, they allow for obtaining exceptionally precise data on the size, shape, and the presence of atmospheres or rings around various objects in the solar system. They play a fundamental role … Read more