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81. Radial velocities of five spectroscopic binaries
ID:
ivo://CDS.VizieR/J/AJ/145/111
Title:
Radial velocities of five spectroscopic binaries
Short Name:
J/AJ/145/111
Date:
21 Oct 2021
Publisher:
CDS
Description:
We have determined spectroscopic orbits for five single-lined spectroscopic binaries, HD100167, HD135991, HD140667, HD158222, HD217924. Their periods range from 60.6 to 2403days and the eccentricities from 0.20 to 0.84. Our spectral classes for the stars confirm that they are of solar type, F9-G5, and all are dwarfs. Their [Fe/H] abundances, determined spectroscopically, are close to the solar value and on average are 0.12 greater than abundances from a photometric calibration. Four of the five stars are rotating faster than their predicted pseudosynchronous rotational velocities.
82. Radial velocities of HD 54371, HR 2692, and 16 UMa
ID:
ivo://CDS.VizieR/J/AJ/149/63
Title:
Radial velocities of HD 54371, HR 2692, and 16 UMa
Short Name:
J/AJ/149/63
Date:
21 Oct 2021
Publisher:
CDS
Description:
With extensive sets of new radial velocities we have determined orbital elements for three previously known spectroscopic binaries, HD 54371, HR 2692, and 16 UMa. All three systems have had the lines of their secondaries detected for the first time. The orbital periods range from 16.24 to 113.23days, and the three binaries have modestly or moderately eccentric orbits. The secondary to primary mass ratios range from 0.50 to 0.64. The orbital dimensions (a_1_sini and a_2_sini) and minimum masses (m_1_sin^3^i and m_2_sin^3^i) of the binary components all have accuracies of {<=}1%. With our spectroscopic results and the Hipparcos data, we also have determined astrometric orbits for two of the three systems, HR 2692 and 16 UMa. The primaries of HD 54371 and 16 UMa are solar-type stars, and their secondaries are likely K or M dwarfs. The primary of HR 2692 is a late-type subgiant and its secondary is a G or K dwarf. The primaries of both HR 2692 and 16 UMa may be pseudosynchronously rotating, while that of HD 54371 is rotating faster than its pseudosynchronous velocity.
83. Radial velocities of massive stars in Cyg OB2
ID:
ivo://CDS.VizieR/J/ApJ/751/4
Title:
Radial velocities of massive stars in Cyg OB2
Short Name:
J/ApJ/751/4
Date:
21 Oct 2021
Publisher:
CDS
Description:
This work provides a statistical analysis of the massive star binary characteristics in the Cygnus OB2 association using radial velocity information of 114 B3-O5 primary stars and orbital properties for the 24 known binaries. We compare these data to a series of Monte Carlo simulations to infer the intrinsic binary fraction and distributions of mass ratios, periods, and eccentricities. We model the distribution of mass ratio, log-period, and eccentricity as power laws and find best-fitting indices of {alpha}=0.1+/-0.5, {beta}=0.2+/-0.4, and {gamma}=-0.6+/-0.3, respectively. These distributions indicate a preference for massive companions, short periods, and low eccentricities. Our analysis indicates that the binary fraction of the cluster is 44%+/-8% if all binary systems are (artificially) assumed to have P<1000 days; if the power-law period distribution is extrapolated to 10^4^ years, then a plausible upper limit for bound systems, the binary fraction is ~90%+/-10%. Of these binary (or higher order) systems, ~45% will have companions close enough to interact during pre- or post-main-sequence evolution (semi-major axis <~4.7AU). The period distribution for P<26 days is not well reproduced by any single power law owing to an excess of systems with periods around 3-5 days (0.08-0.31AU) and a relative shortage of systems with periods around 7-14 days (0.14-0.62AU). We explore the idea that these longer-period systems evolved to produce the observed excess of short-period systems. The best-fitting binary parameters imply that secondaries generate, on average, ~16% of the V-band light in young massive populations. This means that photometrically based distance measurements for young massive clusters and associations will be systematically low by ~8% (0.16 mag in the distance modulus) if the luminous contributions of unresolved secondaries are not taken into account.
84. Radial velocities of 9 O-type stars
ID:
ivo://CDS.VizieR/J/A+A/502/937
Title:
Radial velocities of 9 O-type stars
Short Name:
J/A+A/502/937
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present the results obtained from a long-term spectroscopic campaign to study the multiplicity of O-type stars in both the young open cluster NGC 2244 and the Mon OB2 association. Our spectroscopic monitoring was performed over several years, allowing us to investigate different timescales. For each star, several spectral diagnostic tools were applied to search for line shifts and profile variations. We also measured the projected rotational velocity and revisited the spectral classification.
85. Radial velocities of Praesepe & Hyades Am stars
ID:
ivo://CDS.VizieR/J/A+A/354/881
Title:
Radial velocities of Praesepe & Hyades Am stars
Short Name:
J/A+A/354/881
Date:
21 Oct 2021
Publisher:
CDS
Description:
CORAVEL radial-velocity observations of Am stars in the Hyades and Praesepe have allowed the determination of orbital elements for 10 spectroscopic binaries, among which 3 are first determinations. One Am star (KW 40) is found to be a well hierarchised triple system. KW 538 has a rather long period (435 days) for an Am star. Orbits of systems with periods shorter than 8.5 days are circularized, or present eccentricities smaller than 0.04. For 19 Am stars, the number of quadruple-, triple-, double-, single systems is 1:2:14(10+4?):(2?). The Am stars in a ({beta}, B-V) diagram clearly stand away by 0.03mag from the sequence defined by normal main-sequence stars. This diagram could be a powerful method to identify Am stars in more distant open clusters, provided there is no differential reddening. In the colour-magnitude diagram (M_V_, {beta}), double-lined binaries are 0.6-0.7mag above the ZAMS as expected, while most single-lined are close to or on the ZAMS because the secondary does not contribute much light. The absence of X-ray detection of 4 systems in the Hyades is an argument for the presence of a white dwarf secondary.
86. Radial velocities of SB with M giant
ID:
ivo://CDS.VizieR/J/A+A/498/627
Title:
Radial velocities of SB with M giant
Short Name:
J/A+A/498/627
Date:
21 Oct 2021
Publisher:
CDS
Description:
This paper is a follow-up of the vast effort to collect radial velocity data for stars belonging to the Hipparcos survey. We aim at extending the orbital data available for binaries with M giant primaries. The data will be used in the companion papers of this series to (i) derive the binary frequency among M giants and compare it to that of K giants (Paper II, Frankowski et al., 2009A&A...498..479F), and (ii) analyse the eccentricity-period diagram and the mass-function distribution (Paper III, Jorissen et al., 2009A&A...498..489J). Keplerian solutions are fitted to radial-velocity data. However, for several stars, no satisfactory solution could be found, despite the fact that the radial-velocity standard deviation is larger than the instrumental error, because M giants suffer from intrinsic radial-velocity variations due to pulsations. We show that these intrinsic radial-velocity variations can be linked with both the average spectral-line width and the photometric variability. We present an extensive collection of spectroscopic orbits for M giants, with 12 new orbits, plus 17 from the literature. Moreover, to illustrate the fact that the large radial-velocity jitter present in Mira and semi-regular variables may easily be confused with orbital variations, we also present examples of pseudo-orbital variations (in S UMa, X Cnc and possibly in HD 115521, a former IAU radial-velocity standard). Because of this difficulty, M giants involving Mira variables were excluded from our monitored sample. We finally show that the majority of M giants detected as X-ray sources are actually binaries.
87. Radial velocities of solar-type stars
ID:
ivo://CDS.VizieR/J/ApJS/162/207
Title:
Radial velocities of solar-type stars
Short Name:
J/ApJS/162/207
Date:
21 Oct 2021
Publisher:
CDS
Description:
We studied for duplicity the 167 F7-G8 IV or V primaries within 25pc of the Sun according to their Hipparcos parallaxes and between declinations of -30{deg} and +75{deg}.
88. Radial velocities of southern SIM grid stars
ID:
ivo://CDS.VizieR/J/MNRAS/446/2055
Title:
Radial velocities of southern SIM grid stars
Short Name:
J/MNRAS/446/2055
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present analysis of precision radial velocities (RV) of 1134 mostly red giant stars in the southern sky, selected as candidate astrometric grid objects for the Space Interferometry Mission (SIM). Only a few (typically, two or three) spectroscopic observations per star have been collected, with the main goal of screening binary systems. The estimated rate of spectroscopic binarity in this sample of red giants is 32 per cent at the 0.95 confidence level, and 46 per cent at the 0.75 confidence. The true binarity rate is likely to be higher, because our method is not quite sensitive to very wide binaries and low-mass companions. The estimated lower and upper bounds of stellar RV jitter for the entire sample are 24 and 51m/s, respectively; the adopted mean value is 37m/s. A few objects of interest are identified with large variations of RV, implying abnormally high mass ratios.
89. Radial velocities of 33 spectroscopic binaries
ID:
ivo://CDS.VizieR/J/AJ/145/41
Title:
Radial velocities of 33 spectroscopic binaries
Short Name:
J/AJ/145/41
Date:
21 Oct 2021
Publisher:
CDS
Description:
Orbital elements of 37 single-lined spectroscopic binary systems (SB1s) and 5 double-lined spectroscopic binary systems (SB2s) were determined using high-dispersion spectroscopy. To determine the orbital elements accurately, we carried out precise Doppler shift measurements using the HIgh Dispersion Echelle Spectrograph mounted on the Okayama Astrophysical Observatory 1.88 m telescope. We achieved a radial-velocity precision of ~10 m.s^-1^ over seven years of observations. The targeted binaries have spectral types between F5 and K3, and are brighter than the 7th magnitude in the V band. The orbital elements of 28 SB1s and 5 SB2s were determined at least 10 times more precisely than previous measurements. Among the remaining nine SB1s, five objects were found to be single stars, and the orbital elements of four objects were not determined because our observations did not cover the entire orbital period. We checked the absorption lines from the secondary star for 28 SB1s and found that three objects were in fact SB2s.
90. Radial velocities of stars in NGC 2546
ID:
ivo://CDS.VizieR/J/A+A/633/A146
Title:
Radial velocities of stars in NGC 2546
Short Name:
J/A+A/633/A146
Date:
21 Oct 2021
Publisher:
CDS
Description:
As part of a broader project on the role of binary stars in clusters, we present a spectroscopic study of the open cluster NGC 2546, which is a large cluster lacking previous spectroscopic analysis. We report the finding of two open clusters in the region of NGC 2546. For the two star groups, we determine radial velocity, parallax, proper motion, reddening, distance modulus, and age, using our spectroscopic observations and available photometric and astrometric data, mainly from Gaia Data Release 2 (Gaia DR2). We also determine the orbit of four spectroscopic binaries in these open clusters. From mid-resolution spectroscopic observations for 28 stars in the NGC 2546 region, we determined radial velocities and evaluate velocity variability. To analyze double-lined spectroscopic binaries, we used a spectral separation technique and fit the spectroscopic orbits using a least-squares code. The presence of two stellar groups is suggested by the radial velocity distribution and confirmed by available photometric and astrometric data. We applied a multi-criteria analysis to determine cluster membership, and we obtained kinematic and physical parameters of the clusters. NGC 2546 is actually two clusters, NGC 2546A and NGC 2546B, the are not physically related to each other. NGC 2546A has an age of about 180Myr and a distance of 950pc. It has a half-number radius of 8pc and contains about 480 members brighter than G=18 mag. NGC 2546B is a very young cluster (<10Myr) located at a distance of 1450pc. It is a small cluster with 80 members and a half-number radius of 1.6pc. Stars less massive than 2.5 solar masses in this cluster would be pre- main-sequence objects. We detected four spectroscopic binaries and determined their orbits. The two binaries of NGC 2546A contain chemically peculiar components: HD 68693 is composed of two mercury- manganese stars and HD 68624 has a Bp silicon secondary. Among the most massive objects of NGC 2546B, there are two binary stars: HD 68572, with P=124.2d, and CD -37 4344 with P=10.4d.

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