NGC 1535
Planetary nebula in the constellation of Eridanus
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NGC 1535, also known as Cleopatra's Eye,[3] is a planetary nebula located around 5500-7500 light years away from Earth in the constellation of Eridanus.
| Emission nebula | |
|---|---|
| Planetary nebula | |
NGC 1535 using the 0.8m Schulman Telescope from the Mount Lemmon SkyCenter | |
| Observation data: J2000 epoch | |
| Right ascension | 04h 14m 15.782s[1] |
| Declination | −12° 44′ 21.68″[1] |
| Distance | 5500–7500 ly (1740–2310[2] pc) |
| Apparent magnitude (V) | 10.5[1] |
| Apparent dimensions (V) | 0.650′ × 0.611′[1] |
| Constellation | Eridanus |
| Designations | 2MASX J04141578-1244216, IRAS 04119-1251, PN G 206.4-40.5, PK 206-40.1, dML87 112, UITBOC 627, VERA J0414-1244 |
It was discovered by William Herschel on February 1, 1785.[4] The object is included in the Astronomical League's Herschel 400 Observing Program.[5]
Characteristics
It is very similar to the Eskimo Nebula in both color and structure. It has a round exhibiting moderate ellipticity.[6] The dust distribution inside NGC 1535 is uniform and nearly round in shape. It displays a dust halo with a noticeable inner ring of increased intensity.[7][8] Outside this ring is a faint oval disk, note quite symmetrical with the main nebula. This region shows faint traces of ring formation in the southeastern region.[6][9] The nebula seems to have formed in a somewhat metal-poor region having undergone little or no enhancement of elements mixing with nuclear-processed material.[10]
NGC 1536 is a bright, high-excitatory nebula.[11] Spectra of NGC 1535 from ROSAT reveal of “double hump” shape with approximately one-third of the photons are within the high energy range with more than 0.5 keV. These high energies could not simply have been produced by a stellar photosphere, even with the central star having a temperature of 250,000 Kelvin.[12]
Observations by Leahy et al. using ROSAT reported X-ray emissions from NGC 3587 and NGC 1535. However comparisons between optical and X-ray images shows that these X-ray emissions coincide with a star that was outside the optical boundary of the nebula. This would make previous reports of X-ray emission from NGC 1535 likely false. Observations were taken using ROSAT High Resolution Imager which clearly confirms that the X-ray emissions contain three peaks that are point sources (RX J111447.9+550106, RX J111450.9+550208, and RX J111504.9+550141). Only the first of these sources are projected to be from the central star.[13]
Central star
At the center of NGC 1535, there is a O-type star with a spectral type of O(H)5. It is difficult to visually observe with a magnitude of 10. This star has a mass of 0.59☉ and a temperature of 66,000 Kelvin.[14][15] The star produces stellar winds with a terminal velocity of about 200 km/sec. These stellar winds are suspected to be the dominant force, shaping the morphology of the nebula to a round shape.[16][17]
