Their findings were recently published in the journal Nature Astronomy.
About 5% of RR Lyr stars pulsate with more than one period. Double-period RR Lyr stars are special since the two durations are related to outstanding homes such as mass and essential abundance.
Range and essential abundance measurements for dwarf galaxies and globular clusters. Credit: NAOC
” We discover that the essential abundance can be represented by 2 periods, and hence a period-luminosity relation independent of the essential abundance was developed,” stated Dr. CHEN Xiaodian, lead author of the research study.
Compared to measurements of essential abundance, measurements of period are both simple and precise.
” Our work supplies a method by which range measurements of nearby galaxies can be acquired from photometry alone, without relying on spectroscopic observations,” stated Dr. DENG Licai, a senior scientist at NAOC and co-author of the research study. “This will increase the sample of galaxies with high-precision range by an aspect of 20 or more.”
Double-period RR Lyr stars are important probes that provide not just trusted ranges however also info about essential abundances.
In the coming years, the China Space Station Telescope and the Vera C. Rubin Observatory will find tens of countless double-period RR Lyr stars in neighboring galaxies. Utilizing a range measurement approach based upon double-period RR Lyr stars, we expect to see a 3D instinctive map of the Local Group and acquire a high-precision Hubble constant.
Reference: “The use of double-mode RR Lyrae stars as robust range and metallicity indications” by Xiaodian Chen, Jianxing Zhang, Shu Wang and Licai Deng, 19 June 2023, Nature Astronomy.DOI: 10.1038/ s41550-023-02011-y.
Astronomers have recommended using double-period RR Lyr stars to properly measure galaxy distances. This approach, which can increase the sample of galaxies with accurate distances by over 20 times, gets rid of the need for spectroscopic observations.
The Universe is huge, encompassing hundreds of billions of galaxies. For those galaxies close to us, we primarily determine their ranges utilizing classical Cepheids and RR Lyrae (RR Lyr) stars.
RR Lyr stars are pulsating variables that shine 100 times more brightly than our Sun and are more than twice as old. They can be utilized as a standard candle for determining the ranges of galaxies, due to the tight relationship between their pulsation period and luminosity at the very same elemental abundance.
Based upon this understanding, astronomers from the National Astronomical Observatories of the Chinese Academy of Sciences (NAOC) proposed using double-period RR Lyr stars to measure the distances of galaxies, with the distance error of galaxies being optimized to 1-2%.
Astronomers have actually suggested using double-period RR Lyr stars to properly measure galaxy distances. This method, which can increase the sample of galaxies with precise ranges by over 20 times, removes the need for spectroscopic observations. Above is a 3D intuitive map of the Local Group. Credit: NAOC