The Horsehead Nebula was recently photographed in infrared by NASA’s Hubble Space Telescope in celebration of the 23rd anniversary of the famous telescope’s launch on April 24, 1990.
The Horsehead Nebula is a cloud of thick dust, located just to the south of the bright star Alnitak. It was first ‘discovered’ way back in 1888 by Williamina Fleming at the Harvard College Observatory.
“Looking like an apparition rising from whitecaps of interstellar foam, the iconic Horsehead Nebula has graced astronomy books ever since its discovery more than a century ago. The nebula is a favorite target for amateur and professional astronomers. It is shadowy in optical light. It appears transparent and ethereal when seen at infrared wavelengths. The rich tapestry of the Horsehead Nebula pops out against the backdrop of Milky Way stars and distant galaxies that easily are visible in infrared light.”
The Hubble Telescope has been a part of much of the ground-breaking research done during the last 20 years. “During that time, it has benefited from a slew of upgrades from space shuttle missions, including the 2009 addition of a new imaging workhorse, the high-resolution Wide Field Camera 3 that took the new portrait of the Horsehead.”
The Horsehead Nebula exists as a part of the Orion Molecular Cloud, which is located around 1,500 light-years away in the constellation Orion. “The cloud also contains other well-known objects such as the Great Orion Nebula (M42), the Flame Nebula, and Barnard’s Loop. It is one of the nearest and most easily photographed regions in which massive stars are being formed.”
In the new image, “the backlit wisps along the Horsehead’s upper ridge are being illuminated by Sigma Orionis, a young five-star system just out of view. Along the nebula’s top ridge, two fledgling stars peek out from their now-exposed nurseries.”
“Scientists know a harsh ultraviolet glare from one of these bright stars is slowly evaporating the nebula. Gas clouds surrounding the Horsehead already have dissipated, but the tip of the jutting pillar contains a slightly higher density of hydrogen and helium, laced with dust. This casts a shadow that protects material behind it from being stripped away by intense stellar radiation evaporating the hydrogen cloud, and a pillar structure forms.”