The Crystal Ball Nebula (NGC 1514) is a planetary nebula located in the constellation Taurus, near the border with Perseus. It has an apparent magnitude of 9.43 and lies at an approximate distance of 2,200 light years (700 parsecs) from Earth. It occupies an area of 2.2 arc minutes.
Planetary nebulae are formed when a dying star expels its outer layers of material. They are illuminated by the ultraviolet light from their central star (or stars if it is a binary system), which makes them glow in various colours. They keep expanding away from the star and ultimately disperse into the surrounding space. The estimated expansion rate of NGC 1514 is 25 km/s.
Astronomers have proposed that the nebula surrounds a binary star in a close orbit with a period of 4 to 9 days. The larger primary component in the system is believed to be the source of the expanding gas. A study published in 2003 suggests that the initial mass of the progenitor star was 4.5 solar masses and that the nebula is a product of a common envelope, which forms in close interacting binary systems if there is mass transfer from the primary to the secondary star.
The nebula’s rings, which cannot be seen in visible light, were only discovered in the last decade by the WISE science team at NASA’s Jet Propulsion Laboratory in California, who observed the nebula in infrared light. They believe that the structure of NGC 1514 is similar to other nebulae with an hourglass shape, including the Engraved Hourglass Nebula (MyCn 18) in the constellation Musca, whose rings can be detected at visible wavelengths.
The Crystal Ball Nebula was discovered in November 1790 by William Herschel, the astronomer who had previously coined the term “planetary nebulae” to describe similar deep sky objects with circular shapes resembling those of planets. Before the discovery of NGC 1514, Herschel had believed that nebulae were really densely grouped stars too distant to be resolved in a telescope. NGC 1514 made him rethink his beliefs. He described the nebula as a “most singular phaenomenon,” noting that “the nebulosity about the star is not of a starry nature.”
The Crystal Ball Nebula lies on the border of Taurus and Perseus. The closest bright star in the area is Zeta Persei, a blue supergiant with a visual magnitude of 2.86. Psi Tauri (ψ Tauri) appears somewhat closer to the nebula, but with a magnitude of 5.22, it is not visible from light-polluted areas.
Crystal Ball Nebula – NGC 1514
Right ascension: 04h 09m 16.984s
Declination: +30° 46′ 33.47”
Apparent size: 2′.2
Apparent magnitude: 9.43
Designations: NGC 1514, BD+30 623, IRAS 04061+3038, 2MASS J04091698+3046335, PK 165-15 1, WISE J040916.97+304633.5