Austria 20 Euro 2023

History

20 Euro 2023, KM# 3358, Austria, The Beauty of the Universe, Neutron Star

Obverse. Photo © Austrian Mint

Description

Neutron stars are the remnants of massive stars that have undergone supernova explosions, resulting in some of the densest objects in the universe, second only to black holes. These compact stars, roughly the size of a city with a mass exceeding that of the Sun, are so dense that a teaspoon of neutron star material would weigh as much as 1,000 Cheops pyramids. Estimated to number up to a billion in the Milky Way, neutron stars can rotate at speeds up to 700 times per second and possess magnetic fields millions of times stronger than any man-made magnet.

Neutron stars play a crucial role in gravitational wave astronomy, especially during the merger of binary systems, which generate detectable gravitational waves. While most neutron stars cool and emit little radiation over time, they remain detectable in certain situations, such as when they function as pulsars or are part of binary systems emitting X-rays. These remarkable objects are key to understanding the extremes of matter and cosmic phenomena.

Design: Helmut Andexlinger

Obverse	Geography & astronomy Crab Pulsar Depicts the words ‘crust’ and ‘core’ in German. ‘Crab Pulsar’ is the name of a neutron star that was created from a supernova in the year 1054, while ‘1,4 M ’ refers to the neutron star’s solar mass, ‘30rps’ to its rotation speed per second and ‘r~10km’ to its radius. The Crab Pulsar, located at the center of the Crab Nebula, is a young neutron star formed from the supernova SN 1054, first observed on Earth in 1054. Discovered in 1968, it was the first pulsar linked to a supernova remnant. This pulsar, about 20 kilometers in diameter, rotates 30 times per second, producing powerful beams that make it one of the brightest gamma-ray sources in the sky. The pulsar's wind generates synchrotron emission, lighting up the nebula across the electromagnetic spectrum. The Crab Nebula is also a key calibration source in X-ray astronomy, with its brightness serving as a standard unit of measurement. The issue date, country name and denomination are displayed at the top. 2023 REPUBLIK OESTERREICH 20 EURO KRUSTE KERN r ~ 10 km 30rps 1,4 M ⊚ KREBSPULSAR
Reverse	Colorised Aviation & astronautics Neutron star Depicts a colored illustration of the neutron star bulges with its magnetic field. NEUTRONENSTERN
Edge	Plain