Nikolai Piskunov
Uppsala University
88 Papers
1.4K Citations
Nikolai Piskunov is an academic researcher from Uppsala University. The author has contributed to research in topics: Stars & Magnetic field. The author has an hindex of 37, co-authored 79 publications.
Chat about Author
Papers
Atomic Diffusion and Mixing in Old Stars. I. Very Large Telescope FLAMES-UVES Observations of Stars in NGC 6397
Andreas Korn,Frank Grundahl,Olivier Richard,Lyudmila Mashonkina,Paul S. Barklem,Remo Collet,Bengt Gustafsson,Nikolai Piskunov +7 more
TL;DR: In this paper, a homogeneous photometric and spectroscopic analysis of 18 stars along the evolutionary sequence of the metal-poor globular cluster NGC 6397 ([Fe/H] ≈ -2), from the main-sequence turnoff point to red giants below the bump.
245
M-dwarf metallicities - A high-resolution spectroscopic study in the near infrared
TL;DR: In this article, the authors presented a high-resolution (R~50,000) spectroscopic study of a sample of eight single M dwarfs and three wide-binary systems observed in the infrared J-band.
M-dwarf metallicities. A high-resolution spectroscopic study in the near infrared
TL;DR: In this paper, a high-resolution spectroscopic study of early-type M dwarfs in the infrared was performed using high resolution synthetic spectra based on 1D atmosphere models of late-type stars.
The NASA-UC Eta-Earth Program: I. A Super-Earth Orbiting HD 7924
Andrew W. Howard,John Asher Johnson,Geoffrey W. Marcy,Debra A. Fischer,Jason T. Wright,Gregory W. Henry,Matthew J. Giguere,Howard Isaacson,Jeff A. Valenti,Jay Anderson,Nikolai Piskunov +10 more
TL;DR: In this article, the first low-mass planet was discovered from the NASA-UC Eta-Earth Program, a super-Earth orbiting the K0 dwarf HD 7924.
Radial velocity signatures of Zeeman broadening
Ansgar Reiners,Denis Shulyak,Guillem Anglada-Escudé,S. V. Jeffers,Julien Morin,M. Zechmeister,Oleg Kochukhov,Nikolai Piskunov +7 more
TL;DR: In this paper, the impact of active regions on stellar radial velocity measurements including both temperature contrast in spots and line broadening by the Zeeman effect was investigated. But the authors focused on the effect of temperature contrast and did not consider the effects of magnetic fields.