scholarly journals Study of Spectroscopic Binaries with the Objective Prism Method

1983 ◽  
Vol 62 ◽  
pp. 104-107
Author(s):  
Frank Gieseking
Keyword(s):  
Radial Velocity ◽  
Frequency Distribution ◽  
Radial Velocities ◽  
Spectroscopic Binaries ◽  
Steep Decrease ◽  
Visual Magnitude ◽  
Objective Prism ◽  
The Individual ◽  
Large Telescopes

The frequency distribution of SB’s over apparent visual magnitude emerging from the catalogue of Batten et. al. (1978) shows a very steep decrease of the number of spectroscopically detected SB’s already for such bright stars of magnitude 7. Considering the number of all stars in the individual magnitude intervals, we find a kind of completeness parameter of the spectroscopic surveys: If we scale it somewhat optimistically at 100% between 0 and 3 mag, we see a 50% decrease of the completeness of our knowledge of stellar radial velocities already for stars fainter than 4.5 mag.This situation is mainly due to the fact that the measurement of radial velocities with conventional slit spectrographs is extremely laborious, requiring long exposure times at large telescopes for the exposure of only one spectrum at a time. – Therefore more efficient methods for radial velocity determinations of fainter stars are urgently needed.

scholarly journals Masses of the components of SB2 binaries observed with Gaia – V. Accurate SB2 orbits for 10 binaries and masses of the components of 5 binaries

2020 ◽  
Vol 496 (2) ◽  
pp. 1355-1368
Author(s):  
J-L Halbwachs ◽  
F Kiefer ◽  
Y Lebreton ◽  
H M J Boffin ◽  
F Arenou ◽  
...  
Keyword(s):  
Radial Velocity ◽  
Binary Stars ◽  
Main Sequence ◽  
Spectroscopic Binaries ◽  
Orbital Elements ◽  
Evolved Stars ◽  
The Individual ◽  
The Masses ◽  
Stellar Masses ◽  
Selection Of

ABSTRACT Double-lined spectroscopic binaries (SB2s) are one of the main sources of stellar masses, as additional observations are only needed to give the inclinations of the orbital planes in order to obtain the individual masses of the components. For this reason, we are observing a selection of SB2s using the SOPHIE spectrograph at the Haute-Provence observatory in order to precisely determine their orbital elements. Our objective is to finally obtain masses with an accuracy of the order of one per cent by combining our radial velocity (RV) measurements and the astrometric measurements that will come from the Gaia satellite. We present here the RVs and the re-determined orbits of 10 SB2s. In order to verify the masses, we will derive from Gaia, we obtained interferometric measurements of the ESO VLTI for one of these SB2s. Adding the interferometric or speckle measurements already published by us or by others for four other stars, we finally obtain the masses of the components of five binary stars, with masses ranging from 0.51 to 2.2 solar masses, including main-sequence dwarfs and some more evolved stars whose location in the HR diagram has been estimated.

scholarly journals La Mesure Des Vitesses Radiales Avec Un Prisme Objectif Associe A Un Telescope De Schmidt

1984 ◽  
Vol 78 ◽  
pp. 291-294
Author(s):  
Ch. Fehrenbach ◽  
R. Burnage
Keyword(s):  
Radial Velocity ◽  
Correlation Method ◽  
Probable Error ◽  
Radial Velocities ◽  
Galactic Latitude ◽  
Velocity Measurements ◽  
Schmidt Telescope ◽  
Special Machine ◽  
Objective Prism

AbstractRadial velocity measurements with an objective-prism mounted on a Schmidt telescope.A 62 cm diameter objective-prism is mounted on the CNRS-University of Liège Schmidt telescope at the Haute Provence Observatory. The field is 4 x 4° and the limiting magnitude is 12.5 on IllaJ hyper-sensitised plates. The dispersion is 200 A mm-1 at 4220 A. The plates are measured with a special machine and data are reduced by means of a computer with a correlation method. Stars of all spectral types are measured. The probable error is of some 4 km sec -1 over a mean of at least 3 plates. Already several lists of radial velocities of stars belonging to field situated at -30° of galactic latitude have been published. We have also started radial velocity observations for the Hipparcos Program.

scholarly journals 30. Commission des Vitesses Radiales Stellaires

1936 ◽  
Vol 5 ◽  
pp. 188-196
Author(s):  
M. J. S. Plaskett ◽  
MM. Adams ◽  
Campbell ◽  
Frost ◽  
Guthnick ◽  
...  
Keyword(s):  
Radial Velocity ◽  
Pacific Coast ◽  
Radial Velocities ◽  
University Of Michigan ◽  
University Of Texas ◽  
University Of Toronto ◽  
Visual Magnitude ◽  
Under Construction ◽  
The University

The three years that have elapsed since the Harvard meeting of the Union have witnessed steady progress in the determination of radial velocities. While the three large Pacific Coast Observatories have naturally been able to make the greatest additions to radial velocity work, the Yerkes Observatory, the Simeiz Observatory and the Observatory of the University of Michigan have also made valuable contributions. It is a pleasure to report that there will soon be three major accessions to the list of observatories capable of determining radial velocities. The David Dunlap Observatory of the University of Toronto with its 74-inch telescope, which should be in operation soon after the meeting, will have radial velocities as a prominent feature of its programme. The McDonald Observatory of the University of Texas with an 80-inch telescope now under construction should be ready to commence operations in 1936 and will undertake an extensive radial velocity programme. The Radcliffe Observatory at Oxford has now been granted permission by the Courts to remove to Pretoria, South Africa, and will establish there a 74-inch reflecting telescope, which will also be largely employed in the determination of the urgently needed radial velocities of the southern stars fainter than 5.5 visual magnitude. The Commission may, I believe, congratulate itself that substantial assistance in the preliminary steps leading to this permission of removal was provided by our action at the last meeting in presenting a resolution to the Union, duly passed by the General Assembly, pointing out the urgent need for additional radial velocities in the southern sky, and strongly supporting the project of the Radcliffe Observatory to establish a large telescope at Pretoria.

scholarly journals Gaia Data Release 2

2018 ◽  
Vol 616 ◽  
pp. A6 ◽  
Author(s):  
P. Sartoretti ◽  
D. Katz ◽  
M. Cropper ◽  
P. Panuzzo ◽  
G. M. Seabroke ◽  
...  
Keyword(s):  
Radial Velocity ◽  
Variable Stars ◽  
Radial Velocities ◽  
Spectroscopic Binaries ◽  
Order Estimate ◽  
Parameter Estimates ◽  
First Order ◽  
Processing Pipeline ◽  
Accuracy And Precision ◽  
Data Release

Context. The Gaia Data Release 2 (DR2) contains the first release of radial velocities complementing the kinematic data of a sample of about 7 million relatively bright, late-type stars. Aims. This paper provides a detailed description of the Gaia spectroscopic data processing pipeline, and of the approach adopted to derive the radial velocities presented in DR2. Methods. The pipeline must perform four main tasks: (i) clean and reduce the spectra observed with the Radial Velocity Spectrometer (RVS); (ii) calibrate the RVS instrument, including wavelength, straylight, line-spread function, bias non-uniformity, and photometric zeropoint; (iii) extract the radial velocities; and (iv) verify the accuracy and precision of the results. The radial velocity of a star is obtained through a fit of the RVS spectrum relative to an appropriate synthetic template spectrum. An additional task of the spectroscopic pipeline was to provide first-order estimates of the stellar atmospheric parameters required to select such template spectra. We describe the pipeline features and present the detailed calibration algorithms and software solutions we used to produce the radial velocities published in DR2. Results. The spectroscopic processing pipeline produced median radial velocities for Gaia stars with narrow-band near-IR magnitude GRVS ≤ 12 (i.e. brighter than V ~ 13). Stars identified as double-lined spectroscopic binaries were removed from the pipeline, while variable stars, single-lined, and non-detected double-lined spectroscopic binaries were treated as single stars. The scatter in radial velocity among different observations of a same star, also published in Gaia DR2, provides information about radial velocity variability. For the hottest (Teff ≥ 7000 K) and coolest (Teff ≤ 3500 K) stars, the accuracy and precision of the stellar parameter estimates are not sufficient to allow selection of appropriate templates. The radial velocities obtained for these stars were removed from DR2. The pipeline also provides a first-order estimate of the performance obtained. The overall accuracy of radial velocity measurements is around ~200–300 m s−1, and the overall precision is ~1 km s−1; it reaches ~200 m s−1 for the brightest stars.

Radial Velocity Information in Sour-Type Spectra

1984 ◽  
Vol 88 ◽  
pp. 87-98 ◽  
Author(s):  
W.J. Merline
Keyword(s):  
Radial Velocity ◽  
Signal To Noise Ratio ◽  
A Priori ◽  
Planetary Systems ◽  
High Signal ◽  
Stellar Oscillations ◽  
Rotation Axes ◽  
Visual Magnitude ◽  
Velocity Information ◽  
Large Telescopes

Recent advances in instrumentation and technique have provided hope that changes in stellar radial velocities can be measured with an accuracy of 10 m/s. This tremendous increase in the precision of radial velocity measurements should yield a wealth of new information from studies of stellar oscillations and surface phenomena, as well as offer clues to help answer perhaps the most exciting question, that of the existence of extra-solar planetary systems. The stringent requirements of light scrambling, high signal-to-noise ratio, and the need for frequent or simultaneous calibration (Griffin and Griffin 1973; Serkowski 1978) mean that these new techniques are inherently inefficient. This has limited studies to bright stars and to the use of large telescopes. Without a priori knowledge of the inclination of the rotation axes of the stars under study, searches for planetary systems will require a relatively large number of stars to statistically determine the probability that any of these stars harbor planets. Therefore, it is necessary to extend the limits for precise radial velocity studies to 5th or 6th blue/visual magnitude. Efficient extraction of radial velocity information from the spectrum is essential. Furthermore, attempts to increase limiting precision or decrease limiting magnitudes using conventional techniques will also benefit from increased efficiency.

Positions from objective prism spectra

1978 ◽  
Vol 48 ◽  
pp. 411-415
Author(s):  
J. Stock
Keyword(s):  
Radial Velocity ◽  
Radial Velocities ◽  
Observational Material ◽  
Mathematical Problems ◽  
Objective Prism ◽  
Number Of Authors

Methods for the determination of radial velocities from objective prism plates have been elaborated by a number of authors. K. Schwarzschild was probably the first to analyze the mathematical problems of the method. Fehrenbach has used the radial velocity method extensively, and also Stock and Osbom. A discussion of the possibility of determining accurate positions from the same observational material, however, has been left aside. It is the purpose of this work to show not only that positions of astrometric accuracy can obtained from objective prism plates, but also that such a method offers certain advantages over the more conventional ones.

scholarly journals An Extension of the Search for Spectroscopic Binaries in M3

1985 ◽  
Vol 113 ◽  
pp. 99-101
Author(s):  
Carlton P. Pryor ◽  
David W. Latham ◽  
Martha L. Hazen-Liller
Keyword(s):  
Radial Velocity ◽  
Globular Cluster ◽  
Convincing Evidence ◽  
Time Span ◽  
Radial Velocities ◽  
Spectroscopic Binaries ◽  
Spectroscopic Binary ◽  
Velocity Variations ◽  
Cluster Modelling

We have obtained 295 new radial velocities for the 112 giants in the globular cluster M3 previously observed by Gunn and Griffin. Our velocities have a typical accuracy of 0.8 km/s per measurement and have been combined with the Gunn and Griffin data in order to search for radial velocity variations over a time span of ten years. We find no convincing evidence that any of the giants observed are spectroscopic binaries with one notable exception, von Zeipel 164, which we believe is the first spectroscopic binary to be found in a globular cluster. Modelling of the velocity variations that would be expected in our data for a variety of binary populations confirms Gunn and Griffin's conclusion that binaries with separations of less than 10 AU must occur much less frequently among the giants of M3 than among the population I field stars.

scholarly journals Search for Large Radial Velocities in Direction of NGP Using the Fehrenbach Techniques

1977 ◽  
Vol 4 (2) ◽  
pp. 63-63
Author(s):  
Alphonse Florsch
Keyword(s):  
Radial Velocity ◽  
Data Center ◽  
Radial Velocities ◽  
Growing Up ◽  
The Future ◽  
Objective Prism

The Observatory of Strasbourg will participate in the future in the general radial velocity survey which is in hand at the Observatories of Haute-Provence and of Marseille with FEHRENBACH’s Objective-prism astrograph. A programme of this type, providing a large number of data, is particularly suitable at the place where the “Data Center” is growing up.A radial velocity survey is a vast programme which needs many years to be fulfilled. It is natural that one starts with the most interesting areas in the sky, one of them being the area near NGP. In 1976 twenty fields were covered, each by one plate, in that direction. The whole programme covers 70 overlapping fields in an area of 100 square degrees centered at NGP. The limiting magnitude shall be almost the 12th.

scholarly journals Multiplicity among solar-type stars

2018 ◽  
Vol 619 ◽  
pp. A81 ◽  
Author(s):  
J.-L. Halbwachs ◽  
M. Mayor ◽  
S. Udry
Keyword(s):  
Radial Velocity ◽  
Binary Stars ◽  
Formation Process ◽  
Statistical Properties ◽  
Radial Velocities ◽  
Spectroscopic Binaries ◽  
Orbital Elements ◽  
Velocity Measurements ◽  
Solar Type ◽  
First Time

Context. The statistical properties of binary stars are clues for understanding their formation process. A radial velocity survey was carried on amongst nearby G-type stars and the results were published in 1991. Aims. The survey of radial velocity measurements was extended towards K-type stars. Methods. A sample of 261 K-type stars was observed with the spectrovelocimeter CORAVEL (COrrelation RAdial VELocities). Those stars with a variable radial velocity were detected on the basis of the P(Χ2) test. The orbital elements of the spectroscopic binaries were then derived. Results. The statistical properties of binary stars were derived from these observations and published in 2003. We present the catalogue of the radial velocity measurements obtained with CORAVEL for all the K stars of the survey and the orbital elements derived for 34 spectroscopic systems. In addition, the catalogue contains eight G-type spectroscopic binaries that have received additional measurements since 1991 and for which the orbital elements are revised or derived for the first time.

scholarly journals Search for associations containing young stars (SACY)

2020 ◽  
Vol 645 ◽  
pp. A30
Author(s):  
S. Zúñiga-Fernández ◽  
A. Bayo ◽  
P. Elliott ◽  
C. Zamora ◽  
G. Corvalán ◽  
...  
Keyword(s):  
High Resolution ◽  
Radial Velocity ◽  
Cross Correlation ◽  
Young Stars ◽  
Radial Velocities ◽  
Spectroscopic Binaries ◽  
Substellar Objects ◽  
Apparent Variation ◽  
Stellar Associations

Context. Nearby young associations offer one of the best opportunities for a detailed study of the properties of young stellar and substellar objects thanks to their proximity (<200 pc) and age (∼5−150 Myr). Previous works have identified spectroscopic (<5 au) binaries, close (5−1000 au) visual binaries, and wide or extremely wide (1000−100 000 au) binaries in the young associations. In most of the previous analyses, single-lined spectroscopic binaries (SB1) were identified based on radial velocities variations. However, this apparent variation may also be caused by mechanisms unrelated to multiplicity. Aims. We seek to update the spectroscopy binary fraction of the Search for Associations Containing Young stars (SACY) sample, taking into consideration all possible biases in our identification of binary candidates, such as activity and rotation. Methods. Using high-resolution spectroscopic observations, we produced ∼1300 cross-correlation functions (CCFs) to disentangle the previously mentioned sources of contamination. The radial velocity values we obtained were cross-matched with the literature and then used to revise and update the spectroscopic binary (SB) fraction in each object of the SACY association. In order to better describe the CCF profile, we calculated a set of high-order cross-correlation features to determine the origin of the variations in radial velocities. Results. We identified 68 SB candidates from our sample of 410 objects. Our results hint that at the possibility that the youngest associations have a higher SB fraction. Specifically, we found sensitivity-corrected SB fractions of 22−11+15% for ϵ Cha, 31−14+16% for TW Hya and 32−8+9% for β Pictoris, in contrast to the five oldest associations we have sampled (∼35−125 Myr) which are ∼10% or lower. This result seems independent of the methodology used to asses membership to the associations. Conclusions. The new CCF analysis, radial velocity estimates, and SB candidates are particularly relevant for membership revision of targets in young stellar associations. These targets would be ideal candidates for follow-up campaigns using high-resolution techniques to confirm binarity, resolve orbits, and, ideally, calculate dynamical masses. Additionally, if the results on the SB fraction in the youngest associations were confirmed, it could hint at a non-universal multiplicity among SACY associations.

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