Post by @esoastronomy@mastodon.social

@esoastronomy@mastodon.social 51 min. ago

Perfect #Halloween discovery: dead star and planetary bodies.

Our VLT has found a rare disc of debris around a dead star, a glimpse into the possible fate of our Solar System.

This debris consists of the leftovers of planets that once orbited the star. As the Sun-like star entered the final stages of its life to become the white dwarf J1328−1450, it expanded and shed its outer layers, engulfing and destroying nearby planets.

📷 ESO/L. Calçada

#astrodon #astronomy #astrophysics #space #science

Illustration of a white star surrounded by two concentric brown discs, with a gap between them. There are two small bright points orbiting the star, one embedded in each disc.

#astrophysics #astrodon #science #space #halloween #astronomy

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ESO

@esoastronomy@mastodon.social 50 min. ago

Yet unlike in similar systems previously found, this debris is organised not in only one ring of vaporised planetary rubble, but instead in a double disc, the two parts separated by a clear gap.

This double disc left a characteristic signature in the spectrum of the system, which shows material orbiting at two distinct speeds: a fast inner disc surrounded by a slower outer one.

📷 ESO/L. Calçada

A diagram showing how astronomers can infer the presence of a gaseous disc around a star. Gas only emits light at very specific colours or wavelengths, which can be observed with a spectrograph. This characteristic wavelength will shift to bluer or redder colours if the gas is moving towards us or away from us, respectively. If the gas is rotating around a star, one side of the disc is approaching us and the other one is receding, so its spectrum exhibit two peaks shifted to blue and red colours, as seen to the left of this diagram. The faster the disc spins, the further away the peaks will be from each other. If there are two concentric gas discs, each will produce its own pair of peaks in the spectrum, because they move at different velocities. The outer disc rotates slower than the inner one, so its two peaks are closer to each other.

ESO

@esoastronomy@mastodon.social 50 min. ago

These two discs are likely shaped by two planetesimals that release gas when they interact with dust in the disc as they orbit the star.

Astronomers estimate that the one in the inner ring is the size of a typical asteroid, a few kilometres in diameter, while the outer one could be as large as Pluto, or even our Moon. If they were bigger they would be destroyed by the star's tidal forces.

📹 ESO/L. Calçada

ESO

@esoastronomy@mastodon.social 49 min. ago

The discs contain calcium, oxygen and iron –– a composition similar to that of rocky planetary material found in our own Solar System. But while the inner disc is rich in magnesium that outer one is largely stripped of it. This gives us clues about the origin of the planetesimals that are feeding the discs.

📷 Fortuna and Gentile Fusillo

A painterly drawing of a white star surrounded by two concentric brown discs, with a gap between them. There are two objects orbiting the star, one embedded in each disc. The inner one is an irregular rock, whereas the outer one is larger and rounder. As they move around the star they leave trails behind them.

www.eso.org

Dead star and planetary bodies: astronomers spot unique disc of debris that foretells Solar System’s future

Astronomers using the European Southern Observatory’s Very Large Telescope (ESO’s VLT) have found a rare disc of debris around a dead star that provides a glimpse of what may happen to our Solar System. Unlike in similar systems previously found, the debris — the leftovers of planets that once orbited the star — is organised in a double disc, the two parts separated by a clear gap. The disc appears to be shaped by two planetary bodies, one possibly as big as Pluto, that have survived the violent death of the star.