From ESA Hubble: “Appearances can be deceptive”


Globular clusters are roughly spherical collections of extremely old stars, and around 150 of them are scattered around our galaxy. Hubble is one of the best telescopes for studying these, as its extremely high resolution lets astronomers see individual stars, even in the crowded core. The clusters all look very similar, and in Hubble’s images it can be quite hard to tell them apart – and they all look much like NGC 411, pictured here.

ngc 411

And yet appearances can be deceptive: NGC 411 is in fact not a globular cluster, and its stars are not old. It isn’t even in the Milky Way.

NGC 411 is classified as an open cluster. Less tightly bound than a globular cluster, the stars in open clusters tend to drift apart over time as they age, whereas globulars have survived for well over 10 billion years of galactic history. NGC 411 is a relative youngster — not much more than a tenth of this age. Far from being a relic of the early years of the Universe, the stars in NGC 411 are in fact a fraction of the age of the Sun.

The image is a composite produced from ultraviolet, visible and infrared observations made by Hubble’s Wide Field Camera 3. This filter set lets the telescope “see” colours slightly further beyond red and the violet ends of the spectrum.

Service Mission 4 Day One saw the installation of a new Wide Field (WF) Camera along with a new Science Instrument Command and Data Handling unit (SICDH). Wide Field Camera 3 was constructed at Goddard Space Flight Center and Ball Aerospace in the USA, with some components built by contractors in the UK. WF 3 is a bridge to the advanced infrared observations that will be carried out by Hubble’s successor, the James Web Space Telescope.

See the full article here.

The Hubble Space Telescope is a project of international co-operation between NASA and the European Space Agency.

The main scientific office for Hubble is located at the Space Telescope Science Institute in Baltimore, USA, though the telescope is used by scientists around the world. The education and public outreach office for ESA’s share of the Hubble Space Telescope (known as ESA/Hubble), which runs the website, is located at the headquarters of the European Southern Observatory in Garching, Germany.

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