Effective temperatures of late-type stars - The field giants from K0 to M6

Ridgway, S. T.; Joyce, R. R.; White, N. M.; Wing, R. F.

doi:10.1086/157617

Cited by 196 publications

(139 citation statements)

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“…Because of the difficulties involved in achieving milli-arcsecond resolution, that sample was almost entirely composed of giants with angular diameters measured via Lunar Occultations and Michelson Interferometry (T eff < 5000 K) or Intensity Interferometry (T eff > 6000 K). One of the intriguing results of that analysis was the impossibility of setting the same zero point of the absolute calibration using angular diameters measured by Lunar Occultations (White & Feierman 1987;Ridgway et al 1980) and Michelson Interferometry (Hutter et al 1989;di Benedetto & Rabbia 1987;Mozurkewich et al 1991) with those measured by Intensity Interferometry (Hanbury Brown et al 1974). The absolute calibration (in the Johnson system) proposed by Alonso et al (1994a) is a weighted average from their table 10 and it is interesting to notice that the one derived from Intensity Interferometry alone is 4.8 (J) 1.3 (H) and 4.0 (K) percent lower than the averaged, proposed one.…”

Section: Appendix A: Comparing the Tcs And 2mass Absolute Calibrationmentioning

confidence: 99%

An absolutely calibratedT_effscale from the infrared flux method

Casagrande¹,

Ramírez²,

Meléndez

et al. 2010

A&A

716

104

985

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Various effective temperature scales have been proposed over the years. Despite much work and the high internal precision usually achieved, systematic differences of order 100 K (or more) among various scales are still present. We present an investigation based on the infrared flux method aimed at assessing the source of such discrepancies and pin down their origin. We break the impasse among different scales by using a large set of solar twins, stars which are spectroscopically and photometrically identical to the Sun, to set the absolute zero point of the effective temperature scale to within few degrees. Our newly calibrated, accurate and precise temperature scale applies to dwarfs and subgiants, from super-solar metallicities to the most metal-poor stars currently known. At solar metallicities our results validate spectroscopic effective temperature scales, whereas for [Fe/H] < ∼ −2.5 our temperatures are roughly 100 K hotter than those determined from model fits to the Balmer lines and 200 K hotter than those obtained from the excitation equilibrium of Fe lines. Empirical bolometric corrections and useful relations linking photometric indices to effective temperatures and angular diameters have been derived. Our results take full advantage of the high accuracy reached in absolute calibration in recent years and are further validated by interferometric angular diameters and space based spectrophotometry over a wide range of effective temperatures and metallicities.

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Section: Appendix A: Comparing the Tcs And 2mass Absolute Calibrationmentioning

confidence: 99%

An absolutely calibratedT_effscale from the infrared flux method

Casagrande¹,

Ramírez²,

Meléndez

et al. 2010

A&A

716

104

985

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show abstract

“…4.1). -M dwarfs in our input catalogue with uncertain or probably incorrect spectral types based on apparent magnitudes, r − J colours, and heliocentric distances, including resolved spectral type and class, we also included approximately 50 stars with well-determined spectral types from K3 to M8 for both dwarf (Johnson & Morgan 1953;Kirkpatrick et al 1991;PMSU) and giant classes (e.g., Moore & Paddock 1950;Ridgway et al 1980;Jacoby et al 1984;García 1989;Keenan & McNeil 1989;Kirkpatrick et al 1991;Sánchez-Blázquez et al 2006;Jiménez-Esteban et al 2012). …”

Section: Cafos Samplementioning

confidence: 99%

CARMENES input catalogue of M dwarfs

Alonso-Floriano¹,

Morales²,

Caballero³

et al. 2015

A&A

186

178

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Context. CARMENES is a stabilised, high-resolution, double-channel spectrograph at the 3.5 m Calar Alto telescope. It is optimally designed for radial-velocity surveys of M dwarfs with potentially habitable Earth-mass planets. Aims. We prepare a list of the brightest, single M dwarfs in each spectral subtype observable from the northern hemisphere, from which we will select the best planet-hunting targets for CARMENES. Methods. In this first paper on the preparation of our input catalogue, we compiled a large amount of public data and collected lowresolution optical spectroscopy with CAFOS at the 2.2 m Calar Alto telescope for 753 stars. We derived accurate spectral types using a dense grid of standard stars, a double least-squares minimisation technique, and 31 spectral indices previously defined by other authors. Additionally, we quantified surface gravity, metallicity, and chromospheric activity for all the stars in our sample. Results. We calculated spectral types for all 753 stars, of which 305 are new and 448 are revised. We measured pseudo-equivalent widths of Hα for all the stars in our sample, concluded that chromospheric activity does not affect spectral typing from our indices, and tabulated 49 stars that had been reported to be young stars in open clusters, moving groups, and stellar associations. Of the 753 stars, two are new subdwarf candidates, three are T Tauri stars, 25 are giants, 44 are K dwarfs, and 679 are M dwarfs. Many of the 261 investigated dwarfs in the range M4.0-8.0 V are among the brightest stars known in their spectral subtype. Conclusions. This collection of low-resolution spectroscopic data serves as a candidate target list for the CARMENES survey and can be highly valuable for other radial-velocity surveys of M dwarfs and for studies of cool dwarfs in the solar neighbourhood.

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“…For S Ser we used the photometric diameter to interpret the MIDI data and the diameter corrected with the above law to interpret the K-band data. The spectral types were used to determine temperatures using effective temperature scales by Perrin et al (1998) and Ridgway et al (1980). The central star's diameters and temperatures are listed in Table 2.…”

Section: Stellar Diameter and Temperature Estimatesmentioning

confidence: 99%

High-resolution IR and radio observations of AGB stars

Perrin

Cotton

Millan-Gabet

et al. 2015

A&A

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Aims. We present the results of observations with interferometers of a sample of pulsating asymptotic giant branch (AGB) stars in the infrared and at radio wavelengths. The goal of these observations is to explore the extended stellar atmospheres and to establish links between the spatial scales of molecular envelopes and of the dust shell. This is the key to better understand the process of dust formation and therefore of mass loss. Methods. We used the ESO VLTI/MIDI interferometer in the N band, the Keck Interferometer in the K band, and NRAO VLBA observations of SiO masers at 7 mm wavelength of a sample of AGB stars: U Ari, W Cnc, RX Tau, RT Tau, RT Aql, S Ser, and V Mon. The various instruments probe different altitudes of the atmosphere of the AGB stars. They are sensitive to regions below the silicate dust condensation distance and provide the opportunity of finding hints about how dust and its precursors form in the extended atmosphere of an AGB star. The K-band observations are sensitive to water and carbon-monoxyde vapors. Unfortunately, we were only able to observe S Ser in this wavelength range. Results. We find a ratio of 2.2 between the molecular envelope radius and the photospheric size, which is consistent with previous results. The N-band observations are mostly sensitive to vapors of SiO and water and to dust (alumina and silicate). The silicate dust shell is fully resolved, and no precise parameters can be deduced from the N-band observations other than a spatial extension of at least 12-16 R for our sample. The sizes found for the SiO region are consistent with the radii of the SiO maser rings provided by the VLBA observations. The sizes of the alumina and water vapor regions are systematically found to be larger. There is clear evidence that SiO is absent from regions farther from the star where silicate dust condenses. Conclusions. These observations support a possible scenario in which SiO is adsorbed by species such as corundum. An alternative explanation could be that SiO has chemically disappeared at this range of distances.

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Effective temperatures of late-type stars - The field giants from K0 to M6

Cited by 196 publications

References 0 publications

An absolutely calibratedT_effscale from the infrared flux method

An absolutely calibratedT_effscale from the infrared flux method

CARMENES input catalogue of M dwarfs

High-resolution IR and radio observations of AGB stars

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Effective temperatures of late-type stars - The field giants from K0 to M6

Cited by 196 publications

References 0 publications

An absolutely calibratedTeffscale from the infrared flux method

An absolutely calibratedTeffscale from the infrared flux method

CARMENES input catalogue of M dwarfs

High-resolution IR and radio observations of AGB stars

Contact Info

Product

Resources

About

An absolutely calibratedT_effscale from the infrared flux method

An absolutely calibratedT_effscale from the infrared flux method