PRESTiGE · Precision stellar astrophysics and the distance scale with pulsating stars in the Gaia era
Horizon 2020 — Marie Skłodowska-Curie Actions
- Duration
- 2021-12-01 → 2024-02-28
- EU contribution
- €171,473
- Participants
- 1
- Scheme
- MSCA-IF
Lines connect the coordinator with its partners.
Results in brief
Precision stellar astrophysics and the distance scale with pulsating stars in the Gaia era
The "Precision Stellar Astrophysics and the distance scale with pulsating stars in the Gaia era (PRESTiGE)" project aimed to use classical pulsating stars such as Cepheid and RR Lyrae variables as stellar population tracers for stellar astrophysics and cosmic distance scale. Classical Cepheids have traditionally played a crucial role in providing the primary calibration for the extragalactic distance ladder leading to the most precise determination of the Hubble constant, the present expansion rate of the Universe. Despite extensive use of classical Cepheids and other pulsating stars as standard candles, the absolute calibration of their luminosity scales has not reached a desired percent-level precision due to caveats associated with their geometric parallax distances in our Galaxy, impact of composition and ages on their luminosities among other systematic uncertainties. The PRESTiGE project employed both theoretical and observational efforts to quantify residual systematics in the absolute calibration of Cepheid and RR Lyrae luminosity scales and made a significant progress towards achieving a percent-level precision, which is crucial for the cosmic distance scale studies. We generated state-of-the-art stellar pulsation models of Cepheid and RR Lyrae variables and obtained observational data from several optical and near-infrared telescopes all over the world to achieve the objectives. The project primarily utilised the Gaia space mission data to calibrate the period-luminosity (PL) and period-luminosity-metallicity (PLZ) relations for Cepheid and RR Lyrae variables that are fundamental tools for the extragalactic distance measurements. The project employed innovative and modern computational methods for analysis of observed and theoretical data related to variable stars analysing their pulsation properties, and providing useful constraints for the input of stellar physics to the stellar evolution and pulsation models.
Data: CORDIS, © European Union
Project objective
Classical pulsating stars such as Cepheid and RR Lyrae are sensitive probes for both the stellar astrophysics and the cosmic distance scale. Cepheid variables play a vital role in calibrating extragalactic distance ladder to estimate the local value of the Hubble constant – present expansion rate of the Universe. The current Hubble constant measurement in the late evolutionary Universe based on the Cepheid-Supernovae distance ladder is significantly larger than the Planck mission results from the early Universe. This tension hints at possible new physics beyond the standard cosmological model and warrants a rigorous investigation of potential systematic uncertainties in Cepheid-based distance ladder. The proposed project will use state-of-the-art stellar pulsation models to compute and exploit an unprecedently fine grid of Cepheid and RR Lyrae models. These models together with future Gaia data-releases will be used to calibrate theoretical and empirical Period-Luminosity relations for Cepheid and RR Lyrae, and quantify residual systematic effects in the first-rung of the distance ladder and evaluate the significance of the Hubble tension problem. The project will employ modern computational methods for multiwavelength comparison between predicted and observed pulsation properties and full-amplitude light and velocity variations to constrain the mass-luminosity relations and helium to metal enrichment ratio followed by Cepheid and RR Lyrae stars with sub-percent precision for the first-time. These investigations will also discriminate and quantify the effects of poorly understood non-standard phenomena such as mass-loss, rotation or convective overshooting on input stellar physics to the pulsation codes, and thus imply strong constraints for the stellar evolutionary models. This project is of multidisciplinary nature with a strong transfer of knowledge between the applicant and the host researcher, and in line with the EU strategic plan for research and innovation.
Original text from CORDIS.
Participants
- ISTITUTO NAZIONALE DI ASTROFISICA · ROMACoordinatorItaly
Links
Data: CORDIS, © European Union