A limit on variations in the fine-structure constant from spectra of nearby Sun-like stars

• Published in: arXiv.org
• Main Authors: Murphy, Michael T, Berke, Daniel A, Liu, Fan, Flynn, Chris, Lehmann, Christian, Dzuba, Vladimir A, Flambaum, Victor V
• Format: Paper Journal Article
• Language: English
• Published: Ithaca Cornell University Library, arXiv.org 09.11.2022
• Subjects: Electromagnetic forces; Fine structure; Particle physics; Physics - Astrophysics of Galaxies; Physics - Atomic Physics; Physics - Earth and Planetary Astrophysics; Physics - High Energy Astrophysical Phenomena; Physics - Solar and Stellar Astrophysics; Standard model (particle physics); Stars; Stellar atmospheres; Wavelengths
• ISSN: 2331-8422
• DOI: 10.48550/arxiv.2211.05150

The fine structure constant, \(\alpha\), sets the strength of the electromagnetic force. The Standard Model of particle physics provides no explanation for its value, which could potentially vary. The wavelengths of stellar absorption lines depend on \(\alpha\), but are subject to systematic effects owing to astrophysical processes in stellar atmospheres. We measured precise line wavelengths using 17 stars, selected to have almost identical atmospheric properties to those of the Sun (solar twins), which reduces those systematic effects. We found that \(\alpha\) varies by \(\lesssim\)50 parts-per-billion (ppb) within 50 parsecs from Earth. Combining the results from all 17 stars provides an empirical, local reference for stellar measurements of \(\alpha\) with an ensemble precision of 12 ppb.