IC 4593
| Nebula | |
|---|---|
IC 4593 imaged by astronomer Judy Schmidt | |
| Observation data: J2000.0 epoch | |
| Class | O7f[3] |
| Right ascension | 16h 11m 44.5s[1] |
| Declination | +12° 04′ 17″[2] |
| Distance | 7,900[4] ly |
| Apparent magnitude (V) | 10.7[1] |
| Apparent dimensions (V) | 0.22 × 0.22[1] |
| Constellation | Hercules[1] |
IC 4593 (also known as the White-Eyed Pea Nebula) is a planetary nebula in the constellation Hercules.[1] It was first discovered in 1907 by astronomer Williamina Fleming.[5] The nebula is approximately 0.96 light-years across.[6] At the center of the nebula is a hot white dwarf that's known as HD 145649, which is an O-type star with a spectral type of O7f.[7] The temperature of the white dwarf is approximately 30,000 to 40,000 K.[8][9]
A study published in 2020 found that there are bubbles of extremely hot gas in its inner cavities, with the gas heating to over a million degrees. They were formed because of stellar winds colliding with previously expelled gas.[10]
Characteristics
IC 4593 is homogeneous and amorphous, with little to no clustering when compared to other planetary nebulae.[9][11]
The star is surrounded by an asymmetrical inner core about 10 arcseconds across. The core has a faint but fast gas flow, reaching speeds of over 100 kilometers per second. The star has a dense ring-like structure around it. There are bright, low-ionized knots that extend out of the core and into the inner halo. The knots can be best seen in nitrogen emission lines. The inner halo is partially enclosed by a shell, creating a visible arc shape or bulge near the northwest part of the halo.[12][13]
The outer halo is irregluar and unaligned with the inner halo.[12] The halo is faint and fragmented.[14]
References
- ^ a b c d e "IC 4593 - Planetary Nebula in Hercules | TheSkyLive". theskylive.com. Archived from the original on 2026-01-24. Retrieved 2026-01-15.
- ^ "By Name | NASA/IPAC Extragalactic Database". ned.ipac.caltech.edu. Archived from the original on 2026-01-24. Retrieved 2026-01-15.
- ^ Anandarao, B. G.; Banerjee, D. P. K. (August 19, 1988). "High resolution observations of the planetary nebulae NGC 6153 and IC 4593". Astronomy and Astrophysics. 202: 215–218. Archived from the original on January 24, 2026. Retrieved January 19, 2026 – via ui.adsabs.harvard.edu.
- ^ "IC 4593 - NASA Science". September 11, 2007. Archived from the original on January 24, 2026. Retrieved January 15, 2026.
- ^ "Index Catalog Objects: IC 4550 - 4599". cseligman.com. Archived from the original on 2026-01-24. Retrieved 2026-01-15.
- ^ "Chandra :: Photo Album :: IC 4593 :: November 12, 2020". chandra.cfa.harvard.edu. Archived from the original on January 24, 2026. Retrieved January 16, 2026.
- ^ "Who's who?". Archived from the original on 2026-01-24. Retrieved 2026-01-15.
- ^ "IC4593 Planetary Nebula (HST WFPC2) Unilabs Experiments". Archived from the original on 2026-01-24. Retrieved 2026-01-15.
- ^ a b Czyzak, S. J.; Buerger, E. G.; Aller, L. H. (June 16, 1975). "Spectrophotometric studies of gaseous nebulae. XXIV. The amorphous low-excitation planetary IC 4593". The Astrophysical Journal. 198: 431. Bibcode:1975ApJ...198..431C. doi:10.1086/153618. Archived from the original on January 24, 2026. Retrieved January 16, 2026 – via ui.adsabs.harvard.edu.
- ^ A, Toalá, J; A, Guerrero, M; L, Bianchi; Y-H, Chu; O, De Marco (May 21, 2020). "Chandra observations of the planetary nebula IC 4593". Monthly Notices of the Royal Astronomical Society. 494 (3): 3784–3789. arXiv:2004.04542. doi:10.1093/mnras/staa1024. Archived from the original on January 28, 2026. Retrieved January 15, 2026.
{{cite journal}}: CS1 maint: multiple names: authors list (link) - ^ Buerger, E. G. (March 24, 1973). "Abundances and ionization distribution in planetary nebulae". The Astrophysical Journal. 180: 817. doi:10.1086/152009. Archived from the original on January 24, 2026. Retrieved January 31, 2026 – via ui.adsabs.harvard.edu.
- ^ a b O'Connor, J. A.; Meaburn, J.; López, J. A.; Redman, M. P. (June 17, 1999). "Kinematics of the strange knots and halo of the planetary nebula IC 4593". Astronomy and Astrophysics. 346: 237–242. Archived from the original on January 24, 2026. Retrieved January 17, 2026 – via ui.adsabs.harvard.edu.
- ^ O'Connor, J. A.; Meaburn, J.; López, J. A.; Redman, M. P. (January 17, 2000). "Kinematics of the Asymmetrical Planetary Nebula IC 4593". Asymmetrical Planetary Nebulae II: From Origins to Microstructures. 199: 405. Archived from the original on January 24, 2026. Retrieved January 17, 2026 – via ui.adsabs.harvard.edu.
- ^ Dgani, Ruth; Soker, Noam (March 24, 1998). "Instabilities in Moving Planetary Nebulae". The Astrophysical Journal. 495 (1): 337–345. doi:10.1086/305257. Archived from the original on January 24, 2026. Retrieved January 31, 2026 – via ui.adsabs.harvard.edu.