- ID:
- ivo://CDS.VizieR/J/A+A/318/416
- Title:
- Radial velocities & photometry of classical Cepheids
- Short Name:
- J/A+A/318/416
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Radial velocities and distances have been measured for a sample of 48 remote classical Cepheids located in the outer disc of the Galaxy (118deg<l<274deg). The distances are determined from BVI photometry, with semi-empirical metallicity corrections calibrated on the Magellanic Clouds. Using these Cepheids as tracers, the rotation curve of the disc is determined between R_0_ and 2R_0_. The result is a flat rotation curve about 30km/s lower than theta_0_, V_rot_=193+/-4km/s for R_0_==8.5kpc and theta_0_=220kms/s assumed, or V_rot_=167+/-4km/s for R_0_=8kpc and theta_0_=200km/s. The possible presence of non-axisymmetric components in the rotation of the outer disc is considered. We find a very small or vanishing value for any radial motion of the LSR or expansion/contraction motion.
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- ID:
- ivo://CDS.VizieR/J/A+A/623/A146
- Title:
- Radial Velocity and BIS measurements of Polaris
- Short Name:
- J/A+A/623/A146
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We investigate temporally changing variability amplitudes and the multi- periodicity of the type-I Cepheid Polaris using 162 high-precision radial velocity (RV) and bisector inverse span (BIS) measurements based on optical spectra recorded using Hermes at the 1.2m Flemish Mercator telescope on La Palma, Canary Islands, Spain. Using an empirical template fitting method, we show that Polaris' RV amplitude has been stable to within ~30m/s between September 2011 and November 2018. We apply the template fitting method to publicly accessible, homogeneous RV data sets from the literature and provide an updated solution of Polaris' eccentric 29.3yr orbit. While the inferred pulsation-induced RV amplitudes differ among individual data sets, we find no evidence for time-variable RV amplitudes in any of the separately considered, homogeneous data sets. Additionally, we find that increasing photometric amplitudes determined using SMEI photometry are likely spurious detections due to as yet ill-understood systematic effects of instrumental origin. Given this confusing situation, further analysis of high-quality homogeneous data sets with well-understood systematics is required to confidently establish whether Polaris' variability amplitude is subject to change over time. We confirm periodic bisector variability periods of 3.97d and 40.22d using Hermes BIS measurements and identify a third signal at a period of 60.17d. Although the 60.17d signal dominates the BIS periodogram, we caution that this signal may not be independent of the 40.22d signal. Finally, we show that the 40.22d signal cannot be explained by stellar rotation. Further long-term, high-quality spectroscopic monitoring is required to unravel the complete set of Polaris' periodic signals, which has the potential to provide unprecedented insights into the evolution of Cepheid variables.
- ID:
- ivo://CDS.VizieR/J/A+A/469/1069
- Title:
- Radial velocity curve of {gamma} Peg
- Short Name:
- J/A+A/469/1069
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- With this work we provide observational material to study magnetic field variability of the classical beta Cep-type star gamma Peg. The observations were carried out in the HeI 6678 line in the course of 23 observing nights from 1997 to 2005 with using coude spectrograph in spectropolarimetric mode at the Crimean 2.6m telescope. The behavior of stellar wind was studied in the UV region using data from the IUE satellite (the INES database). It is shown that the UV stellar wind exhibits a variability. A variation of the wind due to stellar pulsations has been detected. In the HeI 6678 line the abnormally blueshifted radial velocities (gamma=-60.57+/-0.29km/s) were detected during a single night in 2005. We do not confirm the 370.5-day orbital period. The most probable orbital period was estimated as P_orb_=6.81608+/-0.00012d. The ratio P_orb_/P_puls_=44.92 appeared to be very close to integer. We have detected the presence of weak magnetic field on the star. The longitudinal component of the field varies from -10G to 30G with the stellar rotation. The most probable rotational period is P_rot_=6.6538+/-0.0016d. Both the orbital and the rotational periods are integral multiple of the difference between them: P_orb_/|P_orb_-P_rot_|=42.002, and P_rot_/|P_orb_-P_rot_|=41.002. Variation of the longitudinal magnetic field during pulsation period with an amplitude about 7G has been detected.
- ID:
- ivo://CDS.VizieR/J/PASP/118/1238
- Title:
- Radial velocity curve of RBS 490
- Short Name:
- J/PASP/118/1238
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- RBS (ROSAT Bright Source) 0490 is a cataclysmic variable star (CV) with unusually strong emission lines. The strength of the emission lines has led to a suggestion that the object is intrinsically faint and correspondingly nearby (33pc), which, if true, would strongly affect estimates of the CV space density. Here we report astrometry, filter photometry, and time-series spectroscopy of this object. The astrometry gives an absolute parallax of 4.5+/-1.5mas and a relative proper motion of 102mas/yr. A Bayesian procedure gives a very uncertain distance estimate of d~300pc, and the small parallax alone implies d>133pc (at 2 standard deviations). The mean V magnitude is 17.4, which implies M_V_=10.9-5log[d/(200pc)], neglecting extinction. At 200pc, the space velocity would be over 90km/s with respect to the local standard of rest. The time-series spectroscopy shows a possible emission-line radial velocity period near 46 minutes. This would be unusually short for an orbital period, and it may represent some other clock in the system.
- ID:
- ivo://CDS.VizieR/J/A+AS/123/209
- Title:
- Radial velocity curve of Sigma Gem
- Short Name:
- J/A+AS/123/209
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The table contains the radial velocities of the RS CVn star sigma Geminorum measured by cross-correlation using Beta Oph as template from the high-resolution SOFIN spectra around 6175A.
- ID:
- ivo://CDS.VizieR/J/MNRAS/396/2194
- Title:
- Radial velocity curve of V440 Per
- Short Name:
- J/MNRAS/396/2194
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- 440 Per is a Population I Cepheid with a period of 7.57d and low-amplitude, almost sinusoidal light and radial velocity curves. With no reliable data on the first harmonic, its pulsation mode identification remained controversial. We obtained a radial velocity curve of V440 Per with our new high-precision and high-throughput Poznan Spectroscopic Telescope.
- ID:
- ivo://CDS.VizieR/J/MNRAS/434/870
- Title:
- Radial velocity curves of 3 Cepheids
- Short Name:
- J/MNRAS/434/870
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present an analysis of spectroscopic radial velocity and photometric data of three bright Galactic Cepheids: LR Trianguli Australis (LR TrA), RZ Velorum (RZ Vel) and BG Velorum (BG Vel). Based on new radial velocity data, these Cepheids have been found to be members of spectroscopic binary systems. The ratio of the peak-to-peak radial velocity amplitude to photometric amplitude indicates the presence of a companion for LR TrA and BG Vel. IUE spectra indicate that the companions of RZ Vel and BG Vel cannot be hot stars. The analysis of all available photometric data revealed that the pulsation period of RZ Vel and BG Vel varies monotonically, due to stellar evolution. Moreover, the longest period Cepheid in this sample, RZ Vel, shows period fluctuations superimposed on the monotonic period increase. The light-time effect interpretation of the observed pattern needs long-term photometric monitoring of this Cepheid. The pulsation period of LR TrA has remained constant since the discovery of its brightness variation. Using statistical data, it is also shown that a large number of spectroscopic binaries still remain to be discovered among bright classical Cepheids.
- ID:
- ivo://CDS.VizieR/J/A+A/622/A164
- Title:
- Radial velocity curves of 11 Cepheids
- Short Name:
- J/A+A/622/A164
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the results of the study of Galactic binary Cepheids combining interferometric and spectroscopic observations. For this purpose, we performed new spectroscopic observations to obtain high-precision radial velocity measurements of the Cepheids (primary component of the systems). We then fit the radial pulsation and orbital velocities to obtain the orbital elements.
- ID:
- ivo://CDS.VizieR/J/MNRAS/469/2089
- Title:
- Radial velocity curves of 7 KIC
- Short Name:
- J/MNRAS/469/2089
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- In this paper, we present high- and middle-resolution spectral observations of seven heartbeat (HB), highly eccentric, Kepler binaries: four of them (KIC 3230227, KIC 03547874, KIC 03749404, KIC 07672068) are SB2 stars and the remaining three (KIC 04949194, KIC 05960989, KIC 10092506) are SB1 stars. The flux amplitudes of their HB signals are from 0.001 to 0.01. Five targets of the sample with eccentricity above 0.64 show tidally induced oscillations, which are harmonics of the orbital period. The orbital and global parameters of all targets were determined as a result of simultaneous modelling of our spectral observations and Kepler photometric data. They exhibit that the masses and radii of some target components do not obey the temperature-mass-radius relation of main-sequence stars. Although our targets do not obey precisely the theoretical period-eccentricity relation, they confirm the previous conclusion that HB stars draw the upper envelope of the eccentricity-period distribution. We did not find simple empirical dependences of the amplitude of the HB signal on the orbital and global parameters of the targets.
- ID:
- ivo://CDS.VizieR/J/A+A/505/1311
- Title:
- Radial velocity curves of 11 UMa and HD 32518
- Short Name:
- J/A+A/505/1311
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- 11 UMi and HD 32518 belong to a sample of 62 K giant stars that has been observed since February 2004 using the 2m Alfred Jensch telescope of the Thueringer Landessternwarte (TLS) to measure precise radial velocities (RVs). The aim of this survey is to investigate the dependence of planet formation on the mass of the host star by searching for planetary companions around intermediate-mass giants.
