NGC 6302
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| Planetary nebula | Lists of nebulae |
|---|---|
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| Observation data (Epoch J2000) |
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| Right ascension | 17h 13m 44.211s[1] |
| Declination | -37° 06′ 15.94″[1] |
| Distance | 3.4 ± 0.5 kly (1.04 ± 0.16 kpc)[2] |
| Apparent magnitude (V) | 7.1B[1] |
| Apparent dimensions (V) | >3′.0[2] |
| Constellation | Scorpius |
| Physical characteristics | |
| Radius | |
| Absolute magnitude (V) | |
| Notable features | |
| Other designations | Bipolar Nebula,[1] Bug Nebula,[1] PK 349+01 1[1] |
NGC 6302 (also called the Bug Nebula or Butterfly Nebula[3]), is a poly-polar planetary nebula in the constellation Scorpius. It is one of the most interesting and complex planetary nebulae observed. The spectrum of NGC 6302 shows it to be one of the hottest objects in the galaxy, with a surface temperature in excess of 200,000 K, implying that the star from which it formed must have been very large.
The central star has never been observed and is surrounded by a particularly dense equatorial disc composed of gas and dust. This dense disc has caused the star's outflows to form a bipolar structure,(Gurzadyan 1997) similar to an hour-glass.
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[edit] History
As it is included in the New General Catalogue, this object has been known since at least 1888. The earliest known study of NGC 6302 is Edward Emerson Barnard in 1907 who drew and described it. (Meaburn et al. 2005)
[edit] Characteristics
NGC 6302 has a complex morphology which may be approximated as bipolar with two primary lobes. A dark lane runs through the waist of the PN optically obscuring the central star. Observations of NGC 6302 suggest that there may be a orthogonal skirt (or chakram) similar to that found in Menzel 3. (Meaburn et al. 2005)
[edit] North west lobe
This PN contains a prominent North-West lobe which extends up to 3′.0 away from the central star and is estimated to have formed from an eruptive event around 1,900 years ago. It has a circular part who's walls precisely follow a Hubble-type outflow. At a angular distance of 1′.71 from the central star, the flow velocity of this lobe is measured to be 263 km/s with an orientation with respect to the plane of the sky of 12.8°. At the extreme periphery of the lobe, the outward velocity exceeds 600 km/s. The western edge of the lobe displays characteristics suggestive of a collision with pre-existing globules of gas which modified the outflow in that region. (Meaburn et al. 2005)
[edit] Dust Chemistry
The prominent dark lane that runs through the centre of the nebula has been shown to have an extraordinary dust chemistry, showing evidence for multiple crystalline silicates and features that have been interpreted by some to be the first extra-solar detection of carbonates. This detection has been disputed, due to the difficulties in forming carbonates in a non-aqueous environment.
[edit] Notes
[edit] References
- Gurzadyan, Grigor A. (1997), The Physics and Dynamics of Planetary Nebulae, Germany: Springer, ISBN 3-540-60965-2
- Meaburn, J.; J. A. López & W. Steffen et al. (2005), "The Hubble-Type Outflows from the High-Excitation, Polypolar Planetary Nebula NGC 6302", The Astronomical Journal 130(5): 2303-2311
- SIMBAD (January 11, 2007), Results for NGC 6302, SIMBAD, Centre de Données Astronomiques de Strasbourg
