PlumX Metrics
Embed PlumX Metrics

The effect of surface gravity on line-depth ratios in the wavelength range 0.97-1.32 μm

Monthly Notices of the Royal Astronomical Society, ISSN: 1365-2966, Vol: 494, Issue: 2, Page: 1724-1734
2020
  • 9
    Citations
  • 0
    Usage
  • 6
    Captures
  • 0
    Mentions
  • 0
    Social Media
Metric Options:   Counts1 Year3 Year

Metrics Details

Article Description

A line-depth ratio (LDR) of two spectral lines with different excitation potentials is expected to be correlated with the effective temperature (Teff). It is possible to determine Teff of a star with a precision of tens of Kelvin if dozens or hundreds of tight LDR-Teff relations can be used. Most of the previous studies on the LDR method were limited to optical wavelengths, but Taniguchi and collaborators reported 81 LDR relations in the YJ band, 0.97-1.32 μm, in 2018. However, with their sample of only 10 giants, it was impossible to account for the effects of surface gravity and metallicity on the LDRs well. Here, we investigate the gravity effect based on YJ-band spectra of 63 stars including dwarfs, giants, and supergiants observed with the WINERED spectrograph. We found that some LDR-Teff relations show clear offsets between the sequence of dwarfs and those of giants/supergiants. The difference between the ionization potentials of the elements considered in each line pair and the corresponding difference in the depths can, at least partly, explain the dependency of the LDR on the surface gravity. In order to expand the stellar parameter ranges that the LDR method can cover with high precision, we obtained new sets of LDR-Teff relations for solar-metal G0-K4 dwarfs and F7-K5 supergiants, respectively. The typical precision that can be achieved with our relations is 10-30 K for both dwarfs and supergiants.

Bibliographic Details

Mingjie Jian; Daisuke Taniguchi; Noriyuki Matsunaga; Naoto Kobayashi; Yuji Ikeda; Chikako Yasui; Sohei Kondo; Hiroaki Sameshima; Satoshi Hamano; Kei Fukue; Akira Arai; Shogo Otsubo; Hideyo Kawakita

Oxford University Press (OUP)

Physics and Astronomy; Earth and Planetary Sciences

Provide Feedback

Have ideas for a new metric? Would you like to see something else here?Let us know