Astrophysicist – CAMK PAN, Warsaw, Poland
Dr. Nikki Miller is an observational astrophysicist who studies the properties of stars similar to our Sun. She holds a postdoctoral research position in the Araucaria group in Warsaw, Poland. Nikki recently finished her PhD at Keele University, developing a new method of measuring the temperatures of stars in eclipsing binaries. Alongside academic research, Nikki is a science communicator and leader at the International Astronomical Youth Camp.
Site last updated: Feb 2023.
There are very few accurate fundamental (direct) measurements of the temperatures of stars similar to our Sun. This is a problem – we need well-studied “benchmark” stars to calibrate theoretical models of stars with, and to check that any results that come out of these models are reliable. Along with my supervisor Dr. Pierre Maxted, I am developing a method to accurately measure the temperatures of stars in eclipsing binary systems. The current industry standard for stellar temperatures is an accuracy of 200-300 K, but in our first paper we achieved results more accurate than 25 K! We hope to apply the method to a number of other eclipsing binaries to build a new set of benchmark stars.
Our headline graph from Miller et al. (2020) [open access link], in which we developed and refined the method on the eclipsing binary AI Phoenicis. We used multi-wavelength observations, along with measurements of stellar radii and distance, to pin down the spectral energy distribution (upper panel) and hence the total flux emitted by each star. We used distortion (lower two panels) to reduce our method’s dependence on stellar models.
PLATO (PLAnetary Transits and Oscillations of stars) is an upcoming ESA mission set to launch in 2026. PLATO will discover and study a large number of extrasolar planets around bright stars, with a dedicated ground-based radial velocity follow-up program. It aims to find Earth-like planets orbiting solar-type stars, but in order to achieve this goal it requires substantial input from stellar astrophysicists: if you want to detect and understand an exoplanet, you need to understand its host star.
I am a member of the PLATO Stellar Science work package WP125500 – PLATO Benchmark Stars, having joined in 2019 as part of the effort to find and characterise eclipsing binary stars that can be used to validate and improve data products from the PLATO mission. I presented work as part of our session at the PLATO STESCI Workshop III in November 2019.
We are in the process of commissioning and testing the hardware and software for our new 2×16″ telescopes, Xamidimura, which have recently replaced the successful planet hunting WASP-South instrument at the South African Astronomical Observatory (SAAO). Once operational, we will use the telescopes for the follow-up of eclipsing binary stars.
In the first year of my PhD, I wrote the scheduling software for Xamidimura which selects optimal targets to observe at any given time. Scheduling sounds straightforward but is not really a trivial task – the software needs to juggle a number of factors while aiming to maximise the scientific output of the instrument. The scheduler is tested and ready to use when the instrument is fully commissioned!
A large proportion of the known population of exoplanets are in short period orbits. Being in such close proximity to a star, especially when the star has a lot of magnetic activity, can lead to planets receiving harsh levels of irradiation in the X-ray and extreme-UV (XUV) part of the spectrum.
Gaps in the distribution of rocky planets or a lack of short-period Neptune-like planets supports the idea that some planets lose significant mass due to irradiation from their host stars. During my masters project, I worked with Prof. Peter Wheatley and others to measure the amount of XUV irradiation that several super-Earth and Neptune sized planets were experiencing.
Are you looking for an engaging speaker to talk to your group about astronomy and space? I’m a passionate science communicator based in Warsaw (PL) available to speak at schools, astronomy societies, science festivals, conferences and private events – virtually or in person!
You can get an idea of some of my past talks and public engagement work below. If you don’t see your particular topic of interest, get in touch and I’d be more than happy to chat about your ideas and create new material for your event!
Topics I can give talks on include but are not limited to:
Many stars form in pairs. In a lot of ways, binary stars are much more interesting than single stars because they interact. Some steal material from their companion star, some crash into each other, some explode. But other binaries are very quiet and well-behaved. These binaries can be studied and measured to a very high precision and accuracy, and are hugely important in calibrating theoretical stellar models.
The first planet to be discovered orbiting around a Sun-like star was found in 1995 (and the discovery won the Nobel Prize in 2019!). Since then, over four thousand other exoplanets have been found; a vast menagerie of weird and wacky worlds, many that are completely different from the ones found in our solar system. Some exoplanets orbit so close to their sun that they’re actually evaporating.
I can speak about general concepts in astronomy, from ancient civilisations to current science. I have also given talks on women in astronomy and the history of space exploration.
I am on the organising committee for Pint of Science Stoke-on-Trent, but we have paused our activities due to the COVID-19 pandemic.
I spoke on a panel about my experiences as a female astrophysicist at the International Day for Women and Girls in Science 2019 event at Keele University.
I have visited schools to chat about astronomy and share the wonderful Keele University Stardome and University of Warwick Planetarium. You can sometimes find me volunteering as a tour guide at Keele Observatory.
As an astronomer who enjoys coding, I had a go at using Apple Shortcuts to make my phone automatically check the weather one hour before sunset and notify me if the sky is forecast to be clear that night. Here’s how I did it. Create a personalised automation Open the Shortcuts app, and tap the … Continue reading Automatic weather alerts with apple shortcuts
I use Python as part of my PhD work almost every day. On most of those days, I use plotting functions to visualise my data and results – either as a “quick and dirty” check that my code is behaving as I expect, or to create publication-standard figures.
Nikki Miller 