Spectral Energy Distributions for Disk and Halo M Dwarfs

By S. Leggett, F. Allard, C. Dahn, Peter Hauschildt, T. Kerr, J. Rayner. 2000

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We have obtained infrared (1-2.5 μm) spectroscopy for 42 halo and disk dwarfs with spectral types M1-M6.5. These data are compared to synthetic spectra generated by the latest model atmospheres of Allard & Hauschildt. Photospheric parameters metallicity, effective temperature, and radius are determined for the sample.We find good agreement between observation and theory except for known problems due to incomplete molecular data for metal hydrides and H2O. The metal-poor M subdwarfs are well matched by the models, as oxide opacity sources are less important in this case. The derived effective temperatures for the sample range from 3600 to 2600 K; at these temperatures grain formation and extinction are not significant in the photosphere. The derived metallicities range from solar to 1/10 solar. The radii and effective temperatures derived agree well with recent models of low-mass stars. The spectra are available in electronic form upon request.

Subfields: Astronomy and Astrophysics, Atmospheric Science, Spectroscopy

View Paper: https://www.semanticscholar.org/paper/3f13301cca87ba3d44dec60301d358f63df1ee37

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Citations in the corpus

Irradiated planets (2001, background): “We have divided our study into two separate cases: one for which the primary star is a dM5 (T eff = 3000K, see Leggett et al. (2000); Allard et al. (2000)) and another where the primary is a G2 solar type star (T eff = 5600K, see Hauschildt et al. (1999)).”
The UKIRT Infrared Deep Sky Survey ZY JHK photometric system: passbands and synthetic colours (2006, background): “…covering the wavelength range i to K, collated from the following references: Geballe et al. (2002), Hawley, Gizis & Reid (1996), Henry, Kirkpatrick & Simons (1996), Kirkpatrick, Henry & Simons (1995), Leggett et al. (2000a; 2001; 2002a), McLean et al. (2003), and Reid, Hawley & Gizis (1995).”
An Empirical Criterion to Classify T Tauri Stars and Substellar Analogs Using Low-Resolution Optical Spectroscopy (2003, unknown): “These color excesses were computed using the measured color indices and spectral type, and the typical color indices corresponding to the spectral type, as listed by Bessell & Brett (1988), Kirkpatrick et al. (2000), and Leggett (1992) and Leggett et al. (2000, 2002).”
Design Considerations for a Ground-Based Transit Search for Habitable Planets Orbiting M Dwarfs (2007, background): “The M★ MK relations of Delfosse et al. (2000), combined with the empirical mass-radius relation of Bayless & Orosz (2006), and the bolometric corrections of Leggett et al. (2000).”
AN EMPIRICAL CALIBRATION TO ESTIMATE COOL DWARF FUNDAMENTAL PARAMETERS FROM H-BAND SPECTRA (2014, background): “…over the last two decades – suffer from incomplete line lists for the molecules that blanket the spectra, particularly for TiO, VO, metal hydrides, and water vapor (e.g. Valenti et al. 1998; Allard et al. 2000; Leggett et al. 2000; Bean et al. 2006;̈Onehag et al. 2012; Rajpurohit et al. 2013).”
First radius measurements of very low mass stars with the VLTI (2002, methodology): “Amongst the sources in Table 2, only GJ 699 has an integrated flux measurement (Leggett et al. 2000), and we thus have to rely on the bolometric correction polynomial fit of (Leggett et al. 2000) to estimate it for the other targets.”
Infrared Photometry of Late-M, L, and T Dwarfs (2001, methodology): “The luminosities of the M to midÈL dwarfs are obtained from Leggett et al. (2000a, 2001) ; those of the T dwarfs Gl 229B and Gl 570D are from Saumon et al. (2000) and Geballe et al. (2001), respectively.”
Theoretical isochrones in several photometric systems I. Johnson-Cousins-Glass, HST/WFPC2, HST/NICMOS, Washington, and ESO Imaging Survey filter sets (2002, result): “…comparable to those found in late-M giants (e.g. the inadequacy of TiO and H2O line lists, and dust formation; see Tsuji et al. 1996, 1999; Leggett et al. 2000), present results compare reasonably well with observational spectral data (see e.g. figure 9 in both Leggett et al. 2000 and 2001).”
The First Substellar Subdwarf? Discovery of a Metal-poor L Dwarf with Halo Kinematics (2003, background): “This pressure-sensitive band, present in late-type L and T dwarfs (Tokunaga & Kobayashi 1999; Burgasser et al. 2002) and cool subdwarfs (Leggett et al. 2000), is generally broad and featureless, consistent with the observed spectrum.”
Are Magnetically Active Low-Mass M Dwarfs Completely Convective? (2001, background): “These yield uncertainties of 100 K (Leggett et al. 2000, hereafter L00) from continuum Ðtting or (in the case of the coolest dwarfs) ^50 K from line proÐle Ðtting (Basri et al. 2000).”
Infrared Spectroscopy of Substellar Objects in Orion (2001, background): “Another study by Leggett et al. (2000) showed little difference due to metallicity in the H bandpass when comparing Disc dwarfs and halo subdwarfs, but much weaker water absorption in halo extreme subdwarfs, in which the H-bandpass profile is dominated by H2 opacity in early M-type dwarfs.”
Identification of New M Dwarfs in the Solar Neighborhood (2003, result): “Using the bolometric corrections from Leggett et al. (2000) gives similar values.”
M dwarfs: effective temperatures, radii and metallicities (2008, methodology): “Our technique returns Teff = 2450 K, cooler then both Leggett et al. (2000) (2600 K) and Golimowski et al. (2004) (2725 K).”
The effective temperature scale of M dwarfs (2013, methodology): “Leggett et al. (1998, 2000) revised their results by comparing the spectral energy distribution and NIR colors of M dwarfs to the same models.”