Tomasz Nowakowski is a writer for Phys.org.
Astronomers using the Five-hundred-meter Aperture Spherical radio Telescope (FAST) have observed a young planetary nebula. The results of the observational campaign were presented in a paper published on May 12 on arXiv.org.
During the evolution of a star into a red giant or white dwarf, shells of gas and dust are ejected from the star. They are important for studying the chemical evolution of stars.
IC 4997 is a young, compact, and rapidly evolving PN located some 8,000 light years away from the Earth. Its temperature is 20,000 K and it has a high surface brightness. The central star has a temperature of around 49,000 K.
A team of astronomy led by Xu-Jia Ouyang of Sun Yat-sen University in Zhuhai, China, has recently performed radio observations of IC 4997 using the tracking mode of the FAST 19-beam receiver. The telescope allowed them to detect neutral atomic hydrogen in this PN, which may have implications for our understanding of its nature.
The first detection from FAST was ofCircumstellar H absorption I in the radio spectrum of IC 4997. The researchers wrote in the paper that this feature came from a shell associated with one of the Na I D lines.
The number of PNe with neutral atomic hydrogen detections is very small compared to the number of verified Galactic PNe. The mass and dynamics of the atomic gas budget could be improved by finding and investigating such features.
The researchers were able to estimate the parameters of the circumstellar H I absorption using the high-resolution and high-sensitivity FAST spectrum. The local standard of rest was measured to be 63.27 km/s, and the full width was found to be 12.74 km/s. The maximum absorption flux density was calculated to be 8.07 mJy, while the integrated flux density was at a level of 136.7 mJy km/s.
The total number of hydrogen atoms in IC 4997 is 17 septendecillion, according to the study. The results suggest that this hydrogen atomic shell was ejected at least 970 years ago during the superwind phase. The neutral atomic hydrogen had a column density of approximately 700 quintillion cm.
The neutral hydrogen in IC 4997 is similar to the ionized nebula in mass, and may have increased over the past 36 years. The total mass is still less than expected. They said that their detection shows the feasibility of using FAST to search for atomic hydrogen in a large sample of PNe and to reveal new insights into the missing mass problem.
More information: Xu-Jia Ouyang et al, FAST search for circumstellar atomic hydrogen–I: the young planetary nebula IC 4997. arXiv:2205.06170v1 [astro-ph.SR], arxiv.org/abs/2205.06170The Science X Network will be launched in 2022.
Citation: Research sheds more light on the properties of young planetary nebula IC 4997 (2022, May 23) retrieved 23 May 2022 from https://phys.org/news/2022-05-properties-young-planetary-nebula-ic.html This document is subject to copyright. Apart from any fair dealing for the purpose of private study or research, no part may be reproduced without the written permission. The content is provided for information purposes only.
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