Characterization of M dwarfs using optical mid-resolution spectra for exploration of small exoplanets

2020/11/30 by Yohei Koizumi, Masayuki Kuzuhara, Masashi Omiya +6 · 8 citations
Chemistry · Physics and Astronomy · #Astronomy #Astronomy and Astrophysical Research #Astrophysics #Effective temperature #Exoplanet #Physics #Spectral line #Spectral resolution #Spectroscopy and Laser Applications #Stars #Stellar classification #Stellar, planetary, and galactic studies #Type (biology) #astro-ph.EP #astro-ph.SR

paper · pdf · doi:10.1093/pasj/psaa112

published in Publications of the Astronomical Society of Japan 73(1), 154-173 (Oxford University Press) · 24 pages, 17 figures, 11 tables. Accepted to be published in Publications of the Astronomical Society of Japan. Please contact us if you need complete version of long tables

arxiv created 2020/11/30 · openalex publication_date 2020/12/02 · openalex created_date 2020/12/07 · arxiv updated 2021/02/17 · openalex updated_date 2026/08/05

Abstract

Abstract We present the optical spectra of 338 nearby M dwarfs, and compute their spectral types, effective temperatures (Teff), and radii. Our spectra were obtained using several optical spectrometers with spectral resolutions that range from 1200 to 10000. As many as 97% of the observed M-type dwarfs have a spectral type of M3–M6, with a typical error of 0.4 subtype, among which the spectral types M4–M5 are the most common. We infer the Teff of our sample by fitting our spectra with theoretical spectra from the PHOENIX model. Our inferred Teff is calibrated with the optical spectra of M dwarfs whose Teff have been well determined with the calibrations that are supported by previous interferometric observations. Our fitting procedures utilize the VO absorption band (7320–7570 Å) and the optical region (5000–8000 Å), yielding typical errors of 128 K (VO band) and 85 K (optical region). We also determine the radii of our sample from their spectral energy distributions. We find most of our sample stars have radii of <0.6 R⊙, with the average error being 3%. Our catalog enables efficient sample selection for exoplanet surveys around nearby M-type dwarfs.

Citations

• The radii of the nearby K5V and K7V stars 61 Cygni A & B
• AN ALL-SKY CATALOG OF BRIGHT M DWARFS
• A standard stellar spectral sequence in the red/near-infrared - Classes K5 to M9
• The 2001 US Naval Observatory Double Star CD-ROM. I. The Washington Double Star Catalog
• Absolute Dimensions of the M‐Type Eclipsing Binary YY Geminorum (Castor C): A Challenge to Evolutionary Models in the Lower Main Sequence
• First radius measurements of very low mass stars with the VLTI
• The Dartmouth Stellar Evolution Database
• THE WIDE-FIELD INFRARED SURVEY EXPLORER (WISE): MISSION DESCRIPTION AND INITIAL ON-ORBIT PERFORMANCE
• PLANET OCCURRENCE WITHIN 0.25 AU OF SOLAR-TYPE STARS FROM KEPLER
• Two nearby M dwarf binaries from the Two Micron All Sky Survey
• The Occurrence Rate of Small Planets around Small Stars
• Spectral Irradiance Calibration in the Infrared. XIV. The Absolute Calibration of 2MASS
• Validation of the new Hipparcos reduction
• Mass-radius relation of low and very low-mass stars revisited with the VLTI
• The Two Micron All Sky Survey (2MASS)
• Gaia Data Release 2
• A discontinuity in the T_{\rm eff}-radius relation of M-dwarfs
• KOOLS–IFU: Kyoto Okayama Optical Low-dispersion Spectrograph with optical-fiber Integral Field Unit