Inclusion of thermohaline mixing, rotation and radiative levitation in stellar evolution calculations
Lead Research Organisation:
Liverpool John Moores University
Department Name: Astrophysics Research Institute
Abstract
The project involves the inclusion of thermohaline mixing, rotation and rotational mixings and radiative levitation in a well established and well tested stellar evolution code (the BaSTI code). The updated code will be employed to address a few outstanding open problems in the interpretation of spectroscopic and photometric observations of young and old massive star clusters.
Studentship Projects
| Project Reference | Relationship | Related To | Start | End | Student Name |
|---|---|---|---|---|---|
| ST/R504932/1 | 01/10/2017 | 31/12/2023 | |||
| 2000204 | Studentship | ST/R504932/1 | 01/10/2017 | 01/04/2021 | Alexander Lisboa-Wright |
| Description | Faculty of Engineering and Teachnology contribution to tuition fees and maintenance grant |
| Amount | £28,280 (GBP) |
| Organisation | Liverpool John Moores University |
| Sector | Academic/University |
| Country | United Kingdom |
| Start | 10/2017 |
| End | 04/2021 |
| Description | Inclusion of thermohaline mixing, rotation and radiative levitation in stellar evolution calculations |
| Amount | £28,280 (GBP) |
| Funding ID | 2000204 |
| Organisation | Science and Technologies Facilities Council (STFC) |
| Sector | Public |
| Country | United Kingdom |
| Start | 10/2017 |
| End | 04/2021 |
| Title | Simple empirical model describing variations in calculated interstellar extinction with changes in stellar atmosphere |
| Description | Reduction in complexity of description of interstellar extinction (calculated from ATLAS9 model atmosphere spectra) from large tables of bolometric correction values to far more simple mathematical models of atmospheric effective temperature, surface gravity and metallicity in all broadband filters in the HST WFC3, HST ACS and Gaia (DR2) photometric filter systems. The model itself expresses the calculated extinction in each of the filters mentioned, normalized to the extinction in the widely-used Johnson-Cousins V-band, as a function of ATLAS9 model atmosphere effective temperature, surface gravity and metallicity. This describes variations in extinction in as little as 3 mathematical coefficients instead of requiring the use of interpolation of large tables of bolometric corrections. |
| Type Of Material | Computer model/algorithm |
| Year Produced | 2019 |
| Provided To Others? | Yes |
| Impact | Great simplification in the empirical description of variations in calculated interstellar extinction. This more easily enables the analysis of impact of star-to-star extinction variations on the predicted global properties of open and globular clusters. In the few open clusters examined, using these simple models produces younger age, greater implied cluster V-band extinction and slightly higher metallicity estimates than are produced using the standard assumption of a constant extinction value in all filters for all stars in a given cluster. |
| URL | https://github.com/AlexlwAstro/phd_work |
| Title | My iPython extinction model calulator |
| Description | All information, including ATLAS9 data tables, the iPython notebook (file name: 'gaia_spectra_plots.ipynb') containing all the functions/routines used to analyze these data and the graphical and numerical results of these analyses showing the form of the chosen mathematical empirical models of extinction and theimpact the subsequent treatment of extinction has on cluster property estimates compared to the standard treatment of extinction |
| Type Of Technology | Software |
| Year Produced | 2019 |
| Impact | Comparing the use of these extinction models, which are based on widely-used stellar model atmospheres and rest on solid theoretical grounds for calculating extinction values in individual stars, for calculating the properties of open and globular clusters to the standard extinction treatment produces divergent estimates of the cluster age, metallicity and V-band extinction, even when using the same CMD data and subsequently placing isochrones in the exact same region of CMD space. |
| URL | https://github.com/AlexlwAstro/phd_work |
| Description | Annual Faculty of Engineering and Technology Research Week. |
| Form Of Engagement Activity | A talk or presentation |
| Part Of Official Scheme? | No |
| Geographic Reach | Local |
| Primary Audience | Postgraduate students |
| Results and Impact | The award research student prepared an A0 poster on each occasion detailing the research project to a postgraduate student and university staff mostly not experts in astrophysics. |
| Year(s) Of Engagement Activity | 2018,2019 |