The ionized hydrogen of the planetary nebula IC 5148C using the Very Large Telescope (VLT) astronomers made observations of the planetary nebula IC 5148. A new study indicates the presence of ionized halogen and determines the fundamental parameters of the central star.
Planetary nebulae are expanding envelopes of gas and dust ejected from a star during its evolution into a red giant or white dwarf. These are relatively rare objects, but they are important for scientists studying the chemical evolution of stars and galaxies. Although IC 5148 (a large planetary nebula) was found in 1894, there is still not much information about it. The nebula is located in the constellation Crane at a distance of 3000 light years from Earth. At an expansion rate of 50 km / s, it is considered one of the fastest known planetary nebulae.
Snapshot of the IC 5148 halo area. Left: after marking the main nebula and eliminating the shape of the halo intensity distribution. Right: also a photo with two circles, centered exactly on 115 and 128 CSPN
To determine more characteristics for IC 5148, researchers used FORS2 and X-SHOOTER spectrometers on the VLT. They managed to obtain low-resolution spectroscopy of the nebula in two angular positions, which were used to study the structure and halo in the optical range 450-880 nm. During the observations, it was possible to detect enhanced radiation characteristics around IC 5148 and to collect important data about the central star of the nebula. In particular, scientists have found that the nebula demonstrates a set of unusual structures in the halo. They look like red-hot ionized material.
The researchers have not yet determined the nature of the emission in halo of IC 5148. They emphasize that the inner area of the halo resembles a perfectly round shape, but the design is visible only from one side of the nebula. More in-depth spectroscopic observations are planned to solve the mystery.
Also managed to get the main characteristics of the central star IC 5148. Its age reaches 8500 years, the average temperature is 11,500 K, and the metallicity is at the level of 0.02 dex. The initial mass of the star reached 1.5 solar.