Dissertation/ Thesis
Exoplanet mass measurement : adaptive optics follow-up of microlensing events
| العنوان: | Exoplanet mass measurement : adaptive optics follow-up of microlensing events |
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| المؤلفون: | Joshua Blackman |
| سنة النشر: | 2020 |
| مصطلحات موضوعية: | astronomy, exoplanets, microlensing, adaptive optics, planetary systems, white dwarfs |
| الوصف: | Microlensing is a powerful tool that can be used to search for cold exoplanets in the disk and bulge of the Milky Way. Over the past 16 years ‚Äöv†¬¿100 planets have been discovered using this method, but moving from modelled parameters to physical properties is difficult. I refine and apply a method of using high-angular resolution near-infrared observations from large ground based observatories to find more precise constraints on the mass and distances of these exoplanets and their stellar hosts. Microlensing events rely on the chance alignment of source and lens stars along our line of sight towards dense star fields, usually the galactic bulge at the centre of our galaxy. The relative proper motion of these two stars is such that adaptive optics (AO) observations on 8-10m class telescopes can be used measure the lens flux, or even entirely resolve them when observed at later epochs. In this thesis I present three studies of microlensing events augmented with AO photometry obtained from the Keck observatory. The first is a reanalysis of the microlensing event MACHO-97-BLG-28. Suspected to be a case where the source and lens stars could be resolved with photometry from Keck, I showed it was not. I revise estimates of the lens mass and distance by re-modelling the event light curve using additional data from the Mt. Stromlo 74‚ÄövÑvp telescope, model estimates of stellar limb darkening, and fitting of the blend separately for each telescope and passband. This slightly favours the conclusion that the event is a stellar M-dwarf binary. I then use Keck photometry to constrain the mass-distance of OGLE-2017-BLG-1434, which is a cold super-Earth planet and the eighth microlensing planet discovered with a planet host star mass ratio q < 1 x 10\\(^{-4}\\). This planet confirms the turnover in the cold-planet mass ratio function. I obtained 60 mas images of the event and by comparing measured near-IR magnitudes with the predicted source magnitude from the light curve model we reduce the error in the lens mass and ... |
| نوع الوثيقة: | thesis |
| اللغة: | unknown |
| Relation: | https://figshare.com/articles/thesis/Exoplanet_mass_measurement_adaptive_optics_follow-up_of_microlensing_events/23253299 |
| DOI: | 10.25959/100.00035905 |
| الاتاحة: | https://doi.org/10.25959/100.00035905 https://figshare.com/articles/thesis/Exoplanet_mass_measurement_adaptive_optics_follow-up_of_microlensing_events/23253299 |
| Rights: | In Copyright |
| رقم الانضمام: | edsbas.BE1198F5 |
| قاعدة البيانات: | BASE |
| DOI: | 10.25959/100.00035905 |
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