NGC 2346
Monoceros | |
|---|---|
| Physical characteristics | |
| Radius | 2 ly |
| Designations | Butterfly Nebula, Bug Nebula[3] |
NGC 2346 is a
spectroscopic binary
, and its unusual shape.
The nebular is bipolar in form, with modest outflow velocities in the range of 8–11 km/s, while the center is girded by an expanding belt of molecular gas. The electron density of the nebula is on the order of 400 per cubic centimeter. The ionization of the nebula is the result of ultraviolet emission from the binary companion.[7] The stronger infrared emission from molecular emission is coming from the belt, which is expanding at the rate of 16 km/s. The mass of the molecular gas in the nebula is estimated to be in the range of 0.34–1.85 M☉, and is much greater than the mass of the ionized gas.[8]
The central star is a
A-type subgiant and a subdwarf O star.[9] The system, which has an orbital period of 16.00±0.03 days,[2] is also variable,[10] probably due to dust in orbit around it. The dust itself is heated by the central star and so NGC 2346 is unusually bright in the infrared part of the spectrum. When one of the two stars evolved into a red giant, it engulfed its companion, which stripped away a ring of material from the larger star's atmosphere. When the red giant's core was exposed, a fast stellar wind
inflated two ‘bubbles’ from either side of the ring.
Gallery
References
- ^ .
- ^ .
- ^ ISBN 9783319188515.
- S2CID 119257242.
- ^ "NGC 2346: A Butterfly-Shaped Planetary Nebula". Astronomy Picture of the Day. October 28, 2001. Retrieved 2020-08-28.
- ISBN 0-933346-84-0.
- doi:10.1086/301170.
- doi:10.1086/324446.
- S2CID 237940344.
- S2CID 255195566.
External links
Media related to NGC 2346 at Wikimedia Commons
