Астронет: Астрономическая картинка дня Мессье 4 http://variable-stars.ru/db/msg/1945805/eng

Explanation: Messier 4 can be found west of bright red-giant star Antares, alpha star of the constellation Scorpius. M4 itself is only just visible from dark sky locations, even though the globular cluster of 100,000 stars or so is a mere 5,500 light-years away. Still, its proximity to prying telescopic eyes makes it a prime target for astronomical explorations. Recent studies have included Hubble observations of M4's pulsating cepheid variable stars, cooling white dwarf stars, and ancient, pulsar orbiting exoplanet PSR B1620-26 b. This sharp image was captured with a small telescope on planet Earth. At M4's estimated distance it spans about 50 light-years across the core of the globular star cluster.

Authors & editors: Robert Nemiroff (MTU) & Jerry Bonnell (USRA)
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