scholarly journals The Velocity Field of S308. The Ring Nebula Around the WN5 Star HD 50896

1982 ◽  
Vol 99 ◽  
pp. 305-309
Author(s):  
Paris Pişmiş ◽  
Alfonso Quintero
Keyword(s):  
Velocity Field ◽  
Radial Velocities ◽  
Expansion Velocity ◽  
Ring Nebula ◽  
Fabry Perot

Radial velocities are determined by Fabry-Pérot interferometry at 131 points of the ring nebula S308. The velocities have yielded a kinematic distance of 1.5 kpc for the object, and an expansion velocity of 45–60 km s−1. The ring nebula has a diameter of 13 pc and the age is estimated to be about 1.5 to 2×105 years.

scholarly journals The Structure and Velocity Field of A78

1989 ◽  
Vol 131 ◽  
pp. 185-185
Author(s):  
P. Pismis ◽  
M. A. Moreno
Keyword(s):  
Velocity Field ◽  
Planetary Nebula ◽  
Image Intensifier ◽  
Radial Velocities ◽  
Central Hole ◽  
Expansion Velocity ◽  
San Pedro ◽  
Systemic Velocity ◽  
Fabry Perot ◽  
The Face

We present a velocity field of the planetary nebula A78 based on three Fabry Pérot Hα (10A) interferograms taken with a focal reducer attached to the 2.1 m reflector of the Observatorio Astronómico Nacional at San Pedro Mártir, Mexico. We have used a single-stage Varo image intensifier and two different étalons with interorder separations of 283 km s−1 (2 interf.) and 100 km s−1 (1 interf.). The scale of the original photographs is 49 arcsec mm−1. Our data have yielded radial velocities in the Hα line at 110 points on the face of A78; the velocity field is far from being smooth. The rings are wide around the central hole, and a few show definite splittings; from these splittings we have estimated an overall expansion velocity of 27 km s−1. The average systemic velocity is found to be around −3 km s−1.

scholarly journals Fabry-Pérot Radial Velocities of S274: a Planetary Nebula

1983 ◽  
Vol 103 ◽  
pp. 547-547
Author(s):  
E. Recillas-Cruz ◽  
P. Pismis
Keyword(s):  
Velocity Field ◽  
Radial Velocity ◽  
Planetary Nebula ◽  
Outer Boundary ◽  
Radial Velocities ◽  
Physical Parameters ◽  
Expansion Velocity ◽  
Double Points ◽  
Fabry Perot ◽  
The Mean

The bright nebula S274 (YM29), 8′ across has been classified as a planetary by Abell (1966) although it has been considered a SNR by other authors. We have determined radial velocities at 173 points on this nebula from four Fabry-Pérot interferograms. The velocity field exhibits a great deal of structure. The average expansion velocity is + 31.5 ± 8 km s−1. The mean radial velocity of S274 is not well determined due to the nature of the velocity field, while the overall velocity (173 points) is + 33 ± 21 km s−1. Points at the outer boundary yield an average of 22 ± 14 km s−1 while the average of the double points is 25 km s−1. The age of expansion of the nebula is estimated at 6.8 × 103yr. The physical parameters of this object are consistent with those of a planetary nebula.

scholarly journals Evidence for non-isotropic mass loss from central stars of some emission nebulae

1979 ◽  
Vol 83 ◽  
pp. 43-46
Author(s):  
Paris Pişmiş
Keyword(s):  
Velocity Field ◽  
Mass Loss ◽  
Ring Nebula ◽  
Fabry Perot ◽  
General Program ◽  
H Ii Region ◽  
Central Stars

In our general program of research on the velocity field of emission nebulae, using the photographic Fabry-Pérot technique, we have included: NGC 6164-5, an H II region with striking symmetry, NGC 2359 a “ring nebula” and Ml-67. The exciting stars in all three are centrally located and are of spectral types 06f (showing P Cygni profiles), WN 5 and WN 8 respectively.

scholarly journals The stellar velocity field in M 51

1970 ◽  
Vol 38 ◽  
pp. 79-82
Author(s):  
S. M. Simkin
Keyword(s):  
Velocity Field ◽  
Large Deviations ◽  
Rotation Curve ◽  
Radial Velocities ◽  
Absorption Lines ◽  
Image Tube ◽  
Stellar Velocity

Radial velocities have been measured from the absorption lines on two image tube spectra of M 51. These velocities show large deviations from the ‘smoothed’ rotation curve for that object. The measurements seem to indicate that both the stars and the gas move in the same way.

scholarly journals Photometry and Kinematics of the Ringed Barred Galaxy NGC 3081

1996 ◽  
Vol 157 ◽  
pp. 244-246
Author(s):  
Guy B. Purcell ◽  
R. Buta
Keyword(s):  
Velocity Field ◽  
Preliminary Analysis ◽  
Fabry Perot ◽  
The Galaxy ◽  
Pattern Speed

AbstractWe present a preliminary analysis of B- and I-band CCD images and Rutgers imaging Fabry–Perot Hα interferometry of the galaxy NGC 3081. We find that the outer R1 and inner ring are both intrinsically oval. We derive a bar pattern speed from the velocity field.

scholarly journals Interferometric Observation of the F-Corona Radial Velocities Field Between 3 and 7 R⊚

1985 ◽  
Vol 85 ◽  
pp. 77-80
Author(s):  
P.V. Shcheglov ◽  
L.I. Shestakova ◽  
A.K. Ajmanov
Keyword(s):  
Scattered Light ◽  
Interplanetary Dust ◽  
Radial Velocities ◽  
The Sun ◽  
Continuous Component ◽  
The North ◽  
The Earth ◽  
Fabry Perot ◽  
Interferometric Observation ◽  
Sky Brightness

AbstractDuring the July 31, 1981 solar eclipse, F-corona interferograms near MgI λ 5184 Å were obtained using a Fabry-Perot etalon (FPE) with an FWHM of 0.5 Å (corresponding to 30 km/sec) and an image tube. Radial velocities Vr of the interplanetary dust (i.d.) were measured in different directions.Both prograde and retrograde motions of i.d. in the ecliptic region is discovered. Most of velocity values do not exceed 50 km/sec. A negative velocity component appears after averaging all Vr for all directions. Its average increases to − 20 km/sec toward the Sun. Some ejections are observed. The strongest (+ 130 km/sec) is located at the north ecliptic pole at a distance of 6 to 7 R⊙.From the lack of unshifted Fraunhofer lines in the scattered sky light, we conclude that the sky brightness continuous component is predominant and its source is K-corona scattered light in the Earth’ s atmosphere.

scholarly journals Kinematic Structure and Chemical Composition of the Double Shell PN NGC 3242

1989 ◽  
Vol 131 ◽  
pp. 200-200
Author(s):  
K. C. Sahu ◽  
S. R. Pottasch ◽  
B. G. Anandarao ◽  
J. N. Desai
Keyword(s):  
Chemical Composition ◽  
High Resolution ◽  
Outer Shell ◽  
Expansion Velocity ◽  
Kinematic Structure ◽  
Line Profiles ◽  
Kinematic Study ◽  
Fabry Perot

Kinematic study of the multiple shell PN NGC 3242 was carried out by obtaining Hα and [O III] line profiles at 9 positions of the nebula using a high-resolution (R ≅ 50,000) Fabry-Pérot spectrometer. The positions cover both the bright inner shell and the faint outer shell. It is shown here that the two apparently continuous shells are kinematically separate: the faint outer shell was ejected ∼ 5000 years earlier and has less expansion velocity than the bright inner shell.

scholarly journals Problems with the Baade Wesselink Method

1989 ◽  
Vol 111 ◽  
pp. 250-250
Author(s):  
E. Böhm-Vitense ◽  
P. Garnavich ◽  
M. Lawler ◽  
J. Mena-Werth ◽  
S. Morgan ◽  
...  
Keyword(s):  
Radial Velocity ◽  
Radial Velocities ◽  
Phase Relations ◽  
Expansion Velocity ◽  
Effective Temperatures ◽  
The Difference

AbstractIt is well known that the Baade-Wesselink method leads to different radii for Cepheids depending on which colors are used to determine the effective temperatures. We try to find the reasons for this discrepancy. We employ yet another version of this method using only maximum and minimum radii, thereby circumventing uncertainties in the phase relations between radial velocities and colors. This has essentially no influence on the derived radii. One major uncertainty is the relation between the photospheric expansion velocity and the measured radial velocity. The main reason for the discrepant results obtained by using different colors appears to be an inconsistency in the difference in the applied temperature-color calibrations. Small changes in the d(log Teff)/d(color) can cause major changes in the derived radii.

Coravel Radial Velocities of Supergiants in the Small Magellanic Cloud

1984 ◽  
Vol 88 ◽  
pp. 265-268
Author(s):  
E. Maurice ◽  
N. Martin ◽  
L. Prévot ◽  
E. Rebeirot
Keyword(s):  
South Africa ◽  
Velocity Field ◽  
Planetary Nebulae ◽  
Hii Regions ◽  
Magellanic Cloud ◽  
Magellanic Clouds ◽  
Radial Velocities ◽  
Small Magellanic Cloud ◽  
Objective Prism

Kinematical studies of the Magellanic Clouds began more than half a century ago, when Wilson, in 1918, first interpreted the gradient of the 17 radial velocities of gazeous nebulae in the Large Cloud in terms of rotation. In the case of the Small Magellanic Cloud, the first real attempt to understand the velocity field of this galaxy was performed by the Radcliffe astronomers (Feast et al., 1960, 1961). Their study was based on radial velocities of 40 stars and 13 HII regions.With the installation by ESO of an objective-prisme astrograph in South Africa, in 1961, and then of several larger telescopes in Chile in 1968, the number of measurements significantly increased for Magellanic objects, in particular in the SMC. In this galaxy, the objective-prism observations resulted in about 100 stellar radial velocities (Florsch, 1972a) of probable members. A compilation by Maurice (1979) of all then known slit-spectrograph radial velocities gave velocities for 80 supergiants, 35 HII regions and 12 planetary nebulae.

scholarly journals The SPIRou wavelength calibration for precise radial velocities in the near infrared

2021 ◽  
Vol 648 ◽  
pp. A48
Author(s):  
M. J. Hobson ◽  
F. Bouchy ◽  
N. J. Cook ◽  
E. Artigau ◽  
C. Moutou ◽  
...  
Keyword(s):  
Hollow Cathode ◽  
Near Infrared ◽  
Wavelength Dependence ◽  
Radial Velocities ◽  
Current Status ◽  
Wavelength Calibration ◽  
Spectral Bands ◽  
Fabry Perot ◽  
Internal Error ◽  
Cavity Width

Aims. SPIRou is a near-infrared (nIR) spectropolarimeter at the CFHT, covering the YJHK nIR spectral bands (980−2350 nm). We describe the development and current status of the SPIRou wavelength calibration in order to obtain precise radial velocities (RVs) in the nIR. Methods. We make use of a UNe hollow-cathode lamp and a Fabry-Pérot étalon to calibrate the pixel-wavelength correspondence for SPIRou. Different methods are developed for identifying the hollow-cathode lines, for calibrating the wavelength dependence of the Fabry-Pérot cavity width, and for combining the two calibrators. Results. The hollow-cathode spectra alone do not provide a sufficiently accurate wavelength solution to meet the design requirements of an internal error of < 0.45 m s−1, for an overall RV precision of 1 m s−1. However, the combination with the Fabry-Pérot spectra allows for significant improvements, leading to an internal error of ∼0.15 m s−1. We examine the inter-night stability, intra-night stability, and impact on the stellar RVs of the wavelength solution.

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