CRIRES-POP Spectra of Cool Stars

The discovery and precise characterisation of exoplanets hinges on good understanding of their host stars. There is growing focus on searching for Earth-mass exoplanets in the habitable zones of M dwarf stars, as their low masses and luminosities will allow easier detection of such Earth analogues. These stars are best studied at near infrared wavelengths, but no high quality empirical M dwarf atlas exists in this region of the spectrum. An important part of the search for habitable planets around M dwarfs is therefore a detailed characterisation of their near infrared spectra.
This project will satisfy this requirement. Our primary aim is to explore the near infrared spectrum of M dwarfs to identify and evaluate regions where planetary markers can be found. We will reduce and analyse high resolution, high signal-to-noise near infrared spectra of the M dwarf Barnard’s Star, observed as part of the CRIRES-POP project, which will provide a public database of high quality near infrared spectra of stars of different spectral types. There is significant overlap of atomic and molecular lines in cool dwarf and cool giant spectra, and in parallel with our M dwarf analysis we will investigate the near infrared spectra of several CRIRES-POP evolved giants.
Our analysis will include making comprehensive line identifications, measuring abundances and isotope ratios, and deriving stellar parameters, resulting in a complete description of each cool star. Our line identification will focus on improving identification of weak lines and resolvable blends, providing feedback to revise incomplete atomic and molecular linelists, which will in turn help improve cool star model atmospheres. We will derive abundances of elements with important lines in the near infrared by fitting synthetic spectra to our observed spectra, the broad wavelength coverage of which will be advantageous to high precision abundance measurements. Combining the spectral information with other available data like optical spectra, colour, and variability information, we will derive properties such as luminosity, radius, and temperature for each star. These full characterisations of cool stars, and their high quality spectra, will be important references for future research.
As the main focus of this project, the M dwarf spectrum will be most rigorously analysed. In particular we will identify and evaluate those regions of the M dwarf spectrum where planetary markers can be found. As well as contributing to a public library of stellar spectral atlases, this project will provide an accurate description of the near infrared spectrum of an M dwarf at a time when there is growing demand in the exoplanet community for such a reference.