@article{EigmuellerChaushevGillenetal.2019,
  author    = {Eigm{\"u}ller, Philipp and Chaushev, Alexander and Gillen, Edward and Smith, Alexis and Nielsen, Louise D. and Turner, Oliver and Csizmadia, Szilard and Smalley, Barry and Bayliss, Daniel and Belardi, Claudia and Bouchy, Francois and Burleigh, Matthew R. and Cabrera, Juan and Casewell, Sarah L. and Chazelas, Bruno and Cooke, Benjamin F. and Erikson, Anders and Gansicke, Boris T. and Guenther, Maximilian N. and Goad, Michael R. and Grange, Andrew and Jackman, James A. G. and Jenkins, James S. and McCormac, James and Moyano, Maximiliano and Pollacco, Don and Poppenh{\"a}ger, Katja and Queloz, Didier and Raynard, Liam and Rauer, Heike and Udry, Stephane and Walker, Simon. R. and Watson, Christopher A. and West, Richard G. and Wheatley, Peter J.},
  title     = {NGTS-5b},
  series = {Astronomy and astrophysics : an international weekly journal},
  volume    = {625},
  journal   = {Astronomy and astrophysics : an international weekly journal},
  publisher = {EDP Sciences},
  address   = {Les Ulis},
  issn      = {1432-0746},
  doi       = {10.1051/0004-6361/201935206},
  pages     = {9},
  year      = {2019},
  abstract  = {Context. Planetary population analysis gives us insight into formation and evolution processes. For short-period planets, the sub-Jovian desert has been discussed in recent years with regard to the planet population in the mass/period and radius/period parameter space without taking stellar parameters into account. The Next Generation Transit Survey (NGTS) is optimised for detecting planets in this regime, which allows for further analysis of the sub-Jovian desert. Aims. With high-precision photometric surveys (e.g. with NGTS and TESS), which aim to detect short period planets especially around M/K-type host stars, stellar parameters need to be accounted for when empirical data are compared to model predictions. Presenting a newly discovered planet at the boundary of the sub-Jovian desert, we analyse its bulk properties and use it to show the properties of exoplanets that border the sub-Jovian desert. Methods. Using NGTS light curve and spectroscopic follow-up observations, we confirm the planetary nature of planet NGTS-5b and determine its mass. Using exoplanet archives, we set the planet in context with other discoveries. Results. NGTS-5b is a short-period planet with an orbital period of 3.3569866 +/- 0.0000026 days. With a mass of 0.229 +/- 0.037 M-Jup and a radius of 1.136 +/- 0.023 R-Jup, it is highly inflated. Its mass places it at the upper boundary of the sub-Jovian desert. Because the host is a K2 dwarf, we need to account for the stellar parameters when NGTS-5b is analysed with regard to planet populations. Conclusions. With red-sensitive surveys (e.g. with NGTS and TESS), we expect many more planets around late-type stars to be detected. An empirical analysis of the sub-Jovian desert should therefore take stellar parameters into account.},
  language  = {en}
}
@article{FusilloTremblayGaensickeetal.2018,
  author    = {Fusillo, Nicola Pietro Gentile and Tremblay, Pier-Emmanuel and G{\"a}nsicke, Boris T. and Manser, Christopher J. and Cunningham, Tim and Cukanovaite, Elena and Hollands, Mark and Marsh, Thomas and Raddi, Roberto and Jordan, Stefan and Toonen, Silvia and Geier, Stephan and Barstow, Martin and Cummings, Jeffrey D.},
  title     = {A Gaia Data Release 2 catalogue of white dwarfs and a comparison with SDSS},
  series = {Monthly notices of the Royal Astronomical Society},
  volume    = {482},
  journal   = {Monthly notices of the Royal Astronomical Society},
  number    = {4},
  publisher = {Oxford Univ. Press},
  address   = {Oxford},
  issn      = {0035-8711},
  doi       = {10.1093/mnras/sty3016},
  pages     = {4570 -- 4591},
  year      = {2018},
  abstract  = {We present a catalogue of white dwarf candidates selected from the second data release of Gaia (DR2). We used a sample of spectroscopically confirmed white dwarfs from the Sloan Digital Sky Survey (SDSS) to map the entire space spanned by these objects in the Gaia Hertzsprung-Russell diagram. We then defined a set of cuts in absolute magnitude, colour, and a number of Gaia quality flags to remove the majority of contaminating objects. Finally, we adopt a method analogous to the one presented in our earlier SDSS photometric catalogues to calculate a probability of being a white dwarf (PWD) for all Gaia sources that passed the initial selection. The final catalogue is composed of 486641 stars with calculated PWD from which it is possible to select a sample of ≃260000 high-confidence white dwarf candidates in the magnitude range 8 < G < 21. By comparing this catalogue with a sample of SDSS white dwarf candidates, we estimate an upper limit in completeness of 85 per cent for white dwarfs with G ≤ 20 mag and Teff >7000 K, at high Galactic latitudes (|b| > 20°). However, the completeness drops at low Galactic latitudes, and the magnitude limit of the catalogue varies significantly across the sky as a function of Gaia's scanning law. We also provide the list of objects within our sample with available SDSS spectroscopy. We use this spectroscopic sample to characterize the observed structure of the white dwarf distribution in the H-R diagram.},
  language  = {en}
}
@article{PelisoliDorschHeberetal.2022,
  author    = {Pelisoli, Ingrid and Dorsch, Matti and Heber, Ulrich and G{\"a}nsicke, Boris and Geier, Stephan and Kupfer, Thomas and Nemeth, Peter and Scaringi, Simone and Schaffenroth, Veronika},
  title     = {Discovery and analysis of three magnetic hot subdwarf stars},
  series = {Monthly notices of the Royal Astronomical Society},
  volume    = {515},
  journal   = {Monthly notices of the Royal Astronomical Society},
  number    = {2},
  publisher = {Oxford University Press},
  address   = {Oxford},
  issn      = {0035-8711},
  doi       = {10.1093/mnras/stac1069},
  pages     = {2496 -- 2510},
  year      = {2022},
  abstract  = {Magnetic fields can play an important role in stellar evolution. Among white dwarfs, the most common stellar remnant, the fraction of magnetic systems is more than 20 per cent. The origin of magnetic fields in white dwarfs, which show strengths ranging from 40 kG to hundreds of MG, is still a topic of debate. In contrast, only one magnetic hot subdwarf star has been identified out of thousands of known systems. Hot subdwarfs are formed from binary interaction, a process often associated with the generation of magnetic fields, and will evolve to become white dwarfs, which makes the lack of detected magnetic hot subdwarfs a puzzling phenomenon. Here we report the discovery of three new magnetic hot subdwarfs with field strengths in the range 300-500 kG. Like the only previously known system, they are all helium-rich O-type stars (He-sdOs). We analysed multiple archival spectra of the three systems and derived their stellar properties. We find that they all lack radial velocity variability, suggesting formation via a merger channel. However, we derive higher than typical hydrogen abundances for their spectral type, which are in disagreement with current model predictions. Our findings suggest a lower limit to the magnetic fraction of hot subdwarfs of 0.147(+0.143)(-0.047) per cent, and provide evidence for merger-induced magnetic fields which could explain white dwarfs with field strengths of 50-150 MG, assuming magnetic flux conservation.},
  language  = {en}
}