Model Photospheres for Late‐Type Stars from the Inversion of High‐Resolution Spectroscopic Observations: Groombridge 1830 and ε Eridani

2000 ◽  
Vol 528 (2) ◽  
pp. 885-895 ◽  
Author(s):  
Carlos Allende Prieto ◽  
Ramon J. Garcia Lopez ◽  
David L. Lambert ◽  
Basilio Ruiz Cobo
Keyword(s):  
High Resolution ◽  
Late Type ◽  
Spectroscopic Observations

scholarly journals Chromospheric activity on late-type star DM UMa using high-resolution spectroscopic observations

2016 ◽  
Vol 459 (1) ◽  
pp. 854-862 ◽  
Author(s):  
LiYun Zhang ◽  
QingFeng Pi ◽  
Xianming L. Han ◽  
Liang Chang ◽  
Daimei Wang
Keyword(s):  
High Resolution ◽  
Type Star ◽  
Late Type ◽  
Spectroscopic Observations ◽  
Chromospheric Activity ◽  
Late Type Star

scholarly journals Model Photospheres for Late‐Type Stars from the Inversion of High‐Resolution Spectroscopic Observations: The Sun

1998 ◽  
Vol 502 (2) ◽  
pp. 951-960 ◽  
Author(s):  
Carlos Allende Prieto ◽  
Basilio Ruiz Cobo ◽  
J. Garcia Lopez
Keyword(s):  
High Resolution ◽  
The Sun ◽  
Late Type ◽  
Spectroscopic Observations

scholarly journals Airglow Derived Measurements of Q-Branch Transition Probabilities for Several Hydroxyl Meinel Bands

Atmosphere ◽  
2019 ◽  
Vol 10 (10) ◽  
pp. 637 ◽  
Author(s):  
Christoph Franzen ◽  
Patrick Joseph Espy ◽  
Niklas Hofmann ◽  
Robert Edward Hibbins ◽  
Anlaug Amanda Djupvik
Keyword(s):  
High Resolution ◽  
Spontaneous Emission ◽  
Transition Probabilities ◽  
High Signal ◽  
Hitran Database ◽  
Signal To Noise ◽  
Optical Telescope ◽  
Spectroscopic Observations ◽  
Emission Transition ◽  
Airglow Emissions

Spectroscopic measurements of the hydroxyl (OH) airglow emissions are often used to infer neutral temperatures near the mesopause. Correct Einstein coefficients for the various transitions in the OH airglow are needed to calculate accurate temperatures. However, studies from some studys showed experimentally and theoretically that the most commonly used Einstein spontaneous emission transition probabilities for the Q-branch of the OH Meinel (6,2) transition are overestimated. Extending their work to several Δv = 2 and 3 transitions from v′ = 3 to 9, we have determined Einstein coefficients for the first four Q-branch rotational lines. These have been derived from high resolution, high signal to noise spectroscopic observations of the OH airglow in the night sky from the Nordic Optical Telescope. The Q-branch Einstein coefficients calculated from these spectra show that values currently tabulated in the HITRAN database overestimate many of the Q-branch transition probabilities. The implications for atmospheric temperatures derived from OH Q-branch measurements are discussed.

scholarly journals Lithium Abundances in Fast Rotating Bright Giant Stars

2004 ◽  
Vol 215 ◽  
pp. 246-247
Author(s):  
J.D. do Nascimento ◽  
A. Lèbre ◽  
R. Konstantinova-Antova ◽  
J. R. de Medeiros
Keyword(s):  
High Resolution ◽  
Class Ii ◽  
Evolutionary Status ◽  
Intermediate Mass ◽  
Luminosity Class ◽  
Spectroscopic Observations ◽  
Giant Stars ◽  
Resonance Doublet ◽  
Li Content ◽  
Fast Rotating

We present the results of high resolution spectroscopic observations of Li I resonance doublet at λ 6707.8 Å for fast rotating single stars of luminosity class II and Ib. We present a discussion on the link between rotation and Li content in intermediate mass giant stars, with emphasis on their evolutionary status. At least one of the observed stars, HD 232862, a G8II with an unusual vsini of 20 km/s, present a Li-rich behavior.

scholarly journals The Art of Surface Imaging

1991 ◽  
Vol 130 ◽  
pp. 309-320 ◽  
Author(s):  
N.E. Piskunov
Keyword(s):  
Inverse Problem ◽  
High Resolution ◽  
Stellar Atmosphere ◽  
High Resolution Spectroscopy ◽  
Regularization Methods ◽  
Problem Solution ◽  
Surface Imaging ◽  
Late Type ◽  
Inverse Problem Solution ◽  
Additional Constraints

AbstractWe intend to analyze the reliability of surface imaging of stars based on high resolution spectroscopy and the technique of inverse problem solution. Both astrophysical and mathematical aspects including different regularization methods are reviewed. The influence of the different factors on the resulting map is discussed and it is shown that the simultaneous use of different kinds of observational data (spectroscopy, photometry, polarimetry etc.) is very useful in providing additional constraints for the solution. The recent results in the surface imaging of Cp- and late-type stars show the way for further progress: the use of more adequate mathematical description of the stellar atmosphere and the simultaneous consideration of various surface inhomogeneities.

scholarly journals Lithium Abundance in Late-Type Stars

2000 ◽  
Vol 198 ◽  
pp. 368-369
Author(s):  
L Pompéia ◽  
B Barbuy ◽  
M. Grenon
Keyword(s):  
High Resolution ◽  
Radial Velocity ◽  
Detailed Analysis ◽  
Absolute Magnitude ◽  
Late Type ◽  
Lithium Abundance ◽  
Dwarf Stars ◽  
The Absolute

We have a list of nearby bulge-like turnoff stars with metallicities in the range −0.3 ≤ [Fe/H] ≤ +0.6, for which we have the absolute magnitude from Hipparcos, Geneva photometry (therefore temperature and metallicity), and radial velocity from Coravel (Grenon 1990, 1997). From Hipparcos data, the turnoff of these field stars indicate an age of 10-11 Gyr, which would be the age of the most metal-rich component of the bulge.We obtained high resolution échelle spectra with FEROS, with the aim to carry out detailed analysis of these stars. In this paper we present the Li abundance for 40 of these metal-rich and old dwarf stars, as a function of their temperatures.

scholarly journals Rotational Velocities of S-Type Symbiotic Stars

2004 ◽  
Vol 215 ◽  
pp. 168-169 ◽  
Author(s):  
Francis C. Fekel ◽  
Kenneth H. Hinkle ◽  
Richard R. Joyce
Keyword(s):  
High Resolution ◽  
Symbiotic Stars ◽  
Spectroscopic Observations ◽  
Empirical Calibration ◽  
Symbiotic Binaries ◽  
The Phoenix

We obtained high-resolution spectroscopic observations at 2.226 μm of 13 S-type symbiotic binaries using the Phoenix infrared spectrograph on Kitt Peak telescopes. from an empirical calibration we determined v sin i values for the giant components. Combined with information from a program to determine orbits, the rotational velocities have been used to estimate the sizes of these stars and the fraction of their Roche lobes that they fill.

scholarly journals 53 Piscium, an SPB Star with Activity

2002 ◽  
Vol 185 ◽  
pp. 236-237
Author(s):  
J.-M. Le Contel ◽  
P. Mathias ◽  
E. Chapellier ◽  
J.-C. Valtier
Keyword(s):  
High Resolution ◽  
False Alarm ◽  
High Frequency ◽  
Signal To Noise Ratio ◽  
High Signal ◽  
Correlation Technique ◽  
Signal To Noise ◽  
Spectroscopic Observations ◽  
Auto Correlation ◽  
Frequency Variations

The star 53 Psc (HD 3379, B2.5IV) has been observed as variable by several authors (Sareyan et al., 1979) with frequencies around 10 c d–1 and has been classified as a β Cephei star. Conversely, other authors (e.g. Percy, 1971) found it to be constant.New high resolution, high signal-to-noise ratio, Spectroscopic observations have been performed at the Observatoire de Haute-Provence in 1996 over 11 nights. The spectral domain covers around 200 Å and is centered on Hδ. Radial velocities were deduced from an auto-correlation technique with a scatter around 0.4kms−1.No high frequency variations are observed. Three frequencies have been detected with a false alarm detection above the 1 % level. A fourth one may be present but its amplitude is below this 1 % level. Results are displayed in Table 1.

scholarly journals Optical Studies of a Local Filament Toward the Magellanic Clouds and a Local IVC Region

1997 ◽  
Vol 166 ◽  
pp. 447-450
Author(s):  
B.E. Penprase ◽  
Q.D. Wang ◽  
U. Herbstmeier
Keyword(s):  
High Resolution ◽  
Interstellar Medium ◽  
Local Region ◽  
Magellanic Clouds ◽  
Optical Studies ◽  
Spectroscopic Observations ◽  
Multiple Components

AbstractWe present new spectroscopic results which constrain the distance of a large IR emitting filament near the LMC, as well as some new results for a local region with widely distributed detections of Intermediate Velocity Clouds (IVCs). We present spectroscopic observations of stars toward both regions which constrain the distances and kinematics of the interstellar features. New optical high resolution (λ/δλ ⋍ 106) spectra have been obtained for the star HD 22252, and are used to estimate approximate distances, temperatures, and pressures within the cloud. An unusual local region of the interstellar medium with several IVCs is also reported, with multiple components of absorption from -80 < υLSR < 70 km s−1 seen toward several stars in the region.

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