IC 5217
Bipolar planetary nebula in Lacerta with a Wolf–Rayet central star.
IC 5217, a planetary nebula located in the northern constellation Lacerta, was first spotted in 1904 by Scottish astronomer Williamina Fleming. Six years later, J. E. L. Dreyer added it to the Second Index Catalogue of Nebulae and Clusters of Stars as entry number 5217. Viewing it requires a telescope, as its apparent visual magnitude is 12.6 and its angular size measures just 7″.
The nebula’s spectra reveal a fairly uniform composition with minimal interstellar absorption. Images show bipolar lobes stretching east to west, extending up to 15″ from the center, with a position angle of 92°. Around the waist, an elongated structure appears to be a bright equatorial ring seen edge-on, perpendicular to the lobes. This ring exhibits a velocity gradient that reaches 27 km s⁻¹ at its leading edges, and radio data indicate it is a flat disk with a hollow center.
The central star exhibits Wolf–Rayet characteristics, classified as spectral type WC 7. It has an apparent visual magnitude of 15.5 and an effective temperature between 92,000 and 95,000 K. The nebula likely formed from an oxygen-rich progenitor and shows lower levels of carbon and helium compared to similar planetary nebulae.
- Constellation
- Lacerta
- Discoverer
- Williamina Fleming
- Discovery year
- 1904
- Apparent visual magnitude
- 12.6
- Angular size
- 7″
- Central star apparent visual magnitude
- 15.5
- Central star effective temperature range
- 92,000–95,000 K
- Central star spectral type
- WC 7
Lore & Background
IC 5217 was discovered in 1904 by Scottish astronomer Williamina Fleming. In 1910, it was included as entry No. 5217 in the Second Index Catalogue of Nebulae and Clusters of Stars by J. E. L. Dreyer. The nebula requires a telescope to view, having an apparent visual magnitude of 12.6 and an angular size of 7″.
Spectra indicate the composition of this nebula is relatively homogeneous with only a low level of interstellar absorption. Images show bipolar lobes oriented along an east-west axis, extending up to 15″ from the midpoint. The orientation of the nebula is along a position angle of 92°. An elongated structure around the waist is likely a bright equatorial ring being viewed from edge-on, at right angles to the lobes. The ring shows a velocity gradient that increases up to 27 km s–1 on the leading edges. Radio data indicates the ring is a flat disk with a hole in the center.
The central star displays Wolf–Rayet characteristics with a spectral type of WC 7. It has an apparent visual magnitude of 15.5 with an effective temperature in the range 92,000–95,000 K. The nebula was probably formed by an oxygen-rich progenitor and appears depleted in carbon and helium compared to similar nebulae.
Reader's Guide
IC 5217 is significant as a planetary nebula with a well-defined bipolar morphology and a central star exhibiting Wolf–Rayet characteristics. Its bipolar lobes extend up to 15″ from the midpoint along an east-west axis, with a position angle of 92°. The equatorial ring, viewed edge-on, is a flat disk with a hole in the center, showing a velocity gradient up to 27 km s–1 on the leading edges. The nebula's composition is relatively homogeneous with low interstellar absorption. The central star, of spectral type WC 7, has an effective temperature between 92,000 and 95,000 K and an apparent visual magnitude of 15.5. The nebula was probably formed by an oxygen-rich progenitor and appears depleted in carbon and helium compared to similar nebulae. These features make IC 5217 a valuable object for studying the evolution of planetary nebulae and their central stars, particularly those with Wolf–Rayet characteristics and bipolar structures.
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