It’s not everyday you get to peek through a keyhole into the world, but Hubble did just that — and didn’t even know it.
A new photo of the Reflection Nebula NGC 1999 taken by the Hubble Space Telescope and released by NASA and the European Space Agency (ESA) on October 24 shows a “peculiar portrait” of the swirling cloud of gas and dust. The nebula is a remnant of the formation of a star, V380 Orion, which can be seen in the center of the image, according to an ESA statement (opens in new tab) which accompanied the picture.
The most distinctive feature of the photo, however, is the dark void at the heart of the keyhole-shaped nebula.
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When the nebula was first photographed by Hubble in 1999, the dark central region was thought to be something known as a “Bock sphere”. These globules are cold clouds of gas, dust and other molecules that are so dense that they block any light from passing through. Only after subsequent observations of the nebula did astronomers learn that the dark region was actually empty space. At present, the origin of this keyhole feature is unknown.
The nebula is lit from within by the newborn star V380 Orion, and the nebula itself is actually the material left over from star formation. The star is white because of the intense heat of its surface – about 18,000 degrees Fahrenheit (10,000 degrees Celsius), or twice the temperature of the sun – and is estimated at 3.5 stellar masses.
The nebula is located near the Orion Nebula, located about 1,500 light-years away, in an active star-forming region of our Milky Way Galaxy. It’s also famous for its proximity to the first Herbig-Haro object ever discovered, which is just outside the frame of the image, according to the space agency. (Herbig-Haro objects are relatively short-lived jets of ionized gas ejected from very young stars.)
The new image was created using archival data from Hubble’s Wide Field Planetary Camera 2, which uses a mix of ultraviolet, visible and near-infrared sensors to create the image of the nebula we see. The infrared sensor is arguably the most important when looking at nebulae, as Hubble’s other sensors cannot see beyond the dust clouds to the stars in or behind the nebula.
This ability of infrared light to pass through clouds of gas and dust is what makes the James Webb Space Telescope such an important instrument, as its infrared camera is much more sensitive than Hubble’s and has already revealed stunning images of famous nebulae such as the Pillars of Creation in the Eagle Nebula.