Understanding Nuclear Cosmochronology: A Deep Dive into Cosmic Age Determination
Explore the fascinating realm of nuclear cosmochronology, a field that utilizes long-lived radioactive nuclides to date cosmic events. Delve into the complexities of cosmic age determination, uncertainties in nuclear chronometers, and the impact of ?-process uncertainties. Gain insights into the methods, challenges, and implications of nuclear cosmochronology in unraveling the mysteries of the cosmos.
Download Presentation
Please find below an Image/Link to download the presentation.
The content on the website is provided AS IS for your information and personal use only. It may not be sold, licensed, or shared on other websites without obtaining consent from the author. If you encounter any issues during the download, it is possible that the publisher has removed the file from their server.
You are allowed to download the files provided on this website for personal or commercial use, subject to the condition that they are used lawfully. All files are the property of their respective owners.
The content on the website is provided AS IS for your information and personal use only. It may not be sold, licensed, or shared on other websites without obtaining consent from the author.
E N D
Presentation Transcript
The 29th International Nuclear Physics Conference (INPC2025) Institute of Basic Science (IBS), Daejeon, Korea, 25-30, May 2025 High-precision nuclear chronometer for the cosmos Xin-Hui Wu / n-hu wu / Department of Physics, Fuzhou University Collaborators Jie Meng, Shuangquan Zhang, Pengwei Zhao @PKU 1 /21
Contents Introduction ?-process simulations Results and discussions Summary 2/21
Introduction 3 /21
Cosmic age Cosmic age is one of the most fundamental quantities in cosmology. Origin and evolution of the Universe Gamow, PR, Phys. Rev., 70, 572 (1946) Dark matter and Dark energy Peebles and Ratra, Rev. Mod. Phys., 75, 559, (2003) Curiosity ! Different methods could lead to different values of cosmic ages. Microwave background radiation: 13.8 Gyr Gravitational lenses: 11.4 Gyr WMAP, (2013); Planck Collaboration, (2018) Jee+, Science, 365, 1134 (2019) Nuclear cosmochronology provides an independent dating technique for cosmos. 4 /21
Nuclear cosmochronology Nuclear cosmochronology predicts the ages by comparing the present and initial abundances of long-lived radioactive nuclides. Fowler and Hoyle, Ann. Phys., 10, 280 (1960) Half-lives of232Th and238U are comparable with the cosmic age, which are suitable for dating stellar ages. National Nuclear Data Center Nuclear chronometers Object: ?-process enhanced metal- poor stars Th X Th X Th/X: Age = 46.51 lg ini lg pre Present abu: Observation U Xini lg U Xpre U/X: Age = 14.84 lg Initial abu: ?-process simulations U Thini lg U Thpre Th/U: Age = 21.80 lg 5 /21
?-process ? -processes happen in explosive astrophysical environments, which produce about half of the elements heavier than Iron. B2FH, RMP, 29, 547 (1957); Cowan+, RMP, 93, 015002, (2021) Kajino+, PPNP, 107, 109 (2019); Key issues of ?-process Astro. environments: Sites and conditions remain uncertainties Nuclear physics inputs: Lack of experimental data; Theoretical uncertainties ?-process uncertainty would lead to the uncertainty of nuclear chronometer. 6 /21
Uncertainty of nuclear chronometer Uncertainties of nuclear chronometers Th/X and U/X chronometer large uncertainty; Sometimes give negative ages. Schatz+, ApJ, 579, 626 (2002) Th/U chronometer Th and U are close to each other; Less affected by ?-process uncertainty. Goriely and Clerbaux, AA, 346, 798 (1999); Cayrel+, Nature, 409, 691 (2001) Astrophysical conditions uncertainty 2 Gyr Wanajo+, ApJ, 577, 853 (2002); Otsuki, Mathews and Kajino, New Astron., 718, 677 (2003) Nuclear physics uncertainty 2 Gyr Schatz+, ApJ, 579, 626 (2002); Niu, Sun, and Meng, PRC, 80, 065806 (2009) Inconsistency of nuclear chronometers Hill+, AA, 387, 560 (2002); Schatz+, ApJ, 579, 626 (2002); Holmbeck+, ApJL, 859, 24 (2018) The ages estimated by different chronometers can be very different. 7 /21
This work A strategy of nuclear chronometer (Th-U-X) is proposed Constrain the astrophysical conditions in the ?-process simulations by synchronizing the Th/X, U/X, and Th/U chronometers. Feasibility and capacity of this new chronometer are studied. This new chronometer is used to investigate the ages of six metal-poor stars, and validate the cosmic age. 8 /21
?-process simulation 9 /21
Nuclear reaction network Nuclear reaction network (7835 nuclei involved) NucNet is adopted Meyer and Adams, MPSS, 42, 5215, (2007) Inputs Nuclear physics Structure and reaction properties Astro. conditions Density and temperature ?? time 10 /21
Nuclear physics inputs Nuclear masses Experiment AME2012 Wang, Huang, Kondev, Audi and Naimi, CPC, 45, 030003 (2021) Theory WS4 , DZ28, FRDM2012, HFB24 Wang, Liu, Wu and Meng, PLB, 734, 215 (2014) M ller, Sierk, Ichikawa, Sagawa, ADNDT, 109-110, 1 (2016) Goriely, Chamel, and Pearson, PRL, 102, 152503 (2009) Duflo and Zuker, PRC, 52, 23 (1995) Neutron capture rates Masses + Talys1.9 Koning, Hilaire, and Duijvestijn, Inte. Conf. on Nucl. Data, 211 (2007) ?-decays ?1/2 1/?5 (modify Q based on FRDM+QRPA ) Moller+, PRC, 67, 055802 (2003) Others JINA database Reaclib2.2 Cyburt+, ApJS, 189, 240 (2010) 11 /21
Astrophysical environments ?-process candidate sites NSM Supported by GW170817 Abbott+, PRL, (2017) Pian+, Nature, (2017) Time-delay Kobayashi+, ApJ, (2020) Heuvel+, MNRAS, (1996) CCSN Had been favorite sites Woosley+, ApJ, (1994) Thompson+, ApJ, (2001) Can happen in the early Universe May only weak ?-process Fischer+, AA, (2010) MHDJ, Collapsar Bisnovatyi-Kogan+, Soviet Astronomy, (1970) strong ?-process Nishimura+, ApJ, (2015) Winteler+, ApJ, (2012) Poor reproduce of abundances Kajino+, PPNP, (2019) Nishimura+, ApJ, (2015) All suffer from some kind of problems. 12 /21
Parametric high-entropy wind Temperature and density ?? time Farouqi, Kratz, Pfeiffer, Rauscher, Thielemann, and Truran, ApJ, 712, 1359 (2010) Parameters and values ?exp 7500 km/s ?9(0) 9 GK ? 5 400 ??/baryon ?0 130 km ?? 0.40 0.48 Superposition of different conditions Reproduce well the Solar ?-process abundance. Farouqi, Kratz, Pfeiffer, Rauscher, Thielemann, and Truran, ApJ, 712, 1359 (2010) Zhao and Zhang, ApJ, 874, 5 (2019) 13 /21
Results and discussions 14/21
Abundances Initial elemental abundances produced by the ?-process simulations under different conditions. XHW, Zhao, Zhang, and Meng, ApJ, 941, 152 (2022) Most simulations can reproduce abundances of stable elements (Z< 75). Th and U abundances remain different among these simulations. 15/21
Th/X, U/X and Th/U chronometer Ages of J2038-0023 predicted by the Th/X, U/X, and Th/U chronometers. XHW, Zhao, Zhang, and Meng, ApJ, 941, 152 (2022) Th/X (U/X): 10 20 Gyr; Th/U: 12.5 14.6 Gyr. Three chronometers predict consistent ages at ?final 305. Synchronizing Th/X, U/X and Th/U chronometers --- Th-U-X chronometer 16/21
Th-U-X chronometer Ages predicted by the Th/U and Th-U-X chronometers, in different astrophysical conditions. Th-U-X XHW, Zhao, Zhang, and Meng, ApJ, 941, 152 (2022) Th/U: 12.5 15.0 Gyr, Variation range 2.5 Gyr. Th-U-X: 14.0 14.2 Gyr, Variation range 0.2 Gyr. 17/21
Nuclear physics uncertainty Ages predicted by the Th-U-X chronometers, based on different nuclear physics inputs. XHW, Zhao, Zhang, and Meng, ApJ, 941, 152 (2022) The variation is ~1 Gyr among these 4 sets of nuclear inputs. 18/21
Stellar ages and cosmic age Ages of six stars predicted by the Th-U-X chronometers, comparing with the cosmic age predicted by different methods. Planck Collaboration, (2018) +0.02 Gyr 13.80 0.02 +1.3 Gyr 11.4 1.0 Jee+, Science, (2019) XHW, Zhao, Zhang, and Meng, ApJ, 941, 152 (2022) The ages of six stars are compatible with cosmic age 13.8 Gyr. Cosmic age 11.4 Gyr by gravitational lenses, is not supported. 19/21
Summary 20/21
Summary A strategy of nuclear chronometer (Th-U-X) is proposed, by synchronizing the Th/X, U/X, and Th/U chronometers. The feasibility and capacity of this strategy are studied. The astrophysical uncertainties of nuclear chronometers are significantly reduced from 2 billion years to within 0.2 billion years. Th-U-X chronometer is used to investigate the ages of six metal- poor stars, and validate the cosmic age. U/X Th/X Synchronization Th-U-X Th/U 21/21
