 |
 |
 |
 |
 |
 |
 |
 |
 |
 |
| . |  |
. |
 by Staff Writers Beijing, China (SPX) May 01, 2019
Small stellar systems like dwarf galaxies are suggested to be the main building blocks of our Galaxy. However, it is unclear how many and what kind of stars in our Galaxy are originated from satellite dwarf galaxies. An international team led by ZHAO Gang, a professor from the National Astronomical Observatories of Chinese Academy of Sciences (NAOC) discovered a chemically peculiar star accreted from a disrupted dwarf galaxy. According to results obtained through the Large Sky Area Multi-Object Fiber Spectroscopic Telescope (LAMOST) and Subaru telescope, the star has an unusually low amount of magnesium which is the eighth most abundant element in the universe. Meanwhile it contains an excessive amount of heavy elements, such as europium, gold, and uranium. The team reported their findings online in Nature Astronomy on April 29th, 2019. "Stars preserve chemical information of its birth site. We can distinguish stars formed in the Milky Way from stars formed in dwarf galaxies based on their chemical abundances," says ZHAO who is also the corresponding author of the paper. The chemical composition of this star that the authors discovered suggests it is originated from a dwarf galaxy which was disrupted by interaction with the Milky Way. The data was obtained by LAMOST, a spectroscopic survey telescope that is capable to take 4,000 spectra in a single exposure. So far LAMOST has obtained more than 8 million stellar spectra for studies of the formation of the Milky Way. "The massive spectra provided by the LAMOST survey give us a great opportunity to find chemically peculiar stars," says XING Qianfan, Ph.D., first author of this paper. his type of stars can be used to explore the chemical evolution of different stellar systems. XING continues, "This newly discovered star with large excesses of heavy elements provides a window for exploring the chemical evolution of disrupted dwarf galaxies. The star formation in dwarf galaxies is relatively slow comparing to larger galaxies, leading to chemical differences among their stellar populations. For instance, the magnesium to iron (Mg/Fe) abundance ratios in stars of dwarf galaxies currently found around the Milky Way are much smaller than those in the majority of stars in the Milky Way." "This is the first discovery of a star having a very low amount of magnesium and an excessive amount of heavy elements," says co-author LI Haining, Ph.D. The extreme enhancement of heavy elements of this star suggests this dwarf galaxy was affected by high-yield rapid neutron-capture process (r-process), the dominant process through which elements heavier than iron are formed. Such process may happen during mergers of binary neutron stars in the dwarf galaxy. "The discovery of this chemically peculiar star is a good start of chemical identification of stars accreted from dwarf galaxies. Such stars will be good tracers for exploring the assemble history of the Milky Way," says ZHAO.
Study details chemical contribution of dwarf galaxy to Milky Way's growth Washington DC (UPI) May 01, 2019 Astronomers are gaining new insights into the way the Milky Way acquires new stellar citizens. Researchers at the National Astronomical Observatories of the Chinese Academy of Sciences have discovered a Milky Way star that accreted from a disrupted dwarf galaxy. Using observations by the Large Sky Area Multi-Object Fiber Spectroscopic Telescope and the Subaru Telescope, astronomers were able to characterize the chemical composition of the alien star. Magnesium is the eighth most a ... read more
|
|||||||||||||
|
|
| The content herein, unless otherwise known to be public domain, are Copyright 1995-2024 - Space Media Network. All websites are published in Australia and are solely subject to Australian law and governed by Fair Use principals for news reporting and research purposes. AFP, UPI and IANS news wire stories are copyright Agence France-Presse, United Press International and Indo-Asia News Service. ESA news reports are copyright European Space Agency. All NASA sourced material is public domain. Additional copyrights may apply in whole or part to other bona fide parties. All articles labeled "by Staff Writers" include reports supplied to Space Media Network by industry news wires, PR agencies, corporate press officers and the like. Such articles are individually curated and edited by Space Media Network staff on the basis of the report's information value to our industry and professional readership. Advertising does not imply endorsement, agreement or approval of any opinions, statements or information provided by Space Media Network on any Web page published or hosted by Space Media Network. General Data Protection Regulation (GDPR) Statement Our advertisers use various cookies and the like to deliver the best ad banner available at one time. All network advertising suppliers have GDPR policies (Legitimate Interest) that conform with EU regulations for data collection. By using our websites you consent to cookie based advertising. If you do not agree with this then you must stop using the websites from May 25, 2018. Privacy Statement. Additional information can be found here at About Us. |
del.icio.us
Digg
Reddit
Google
