- ID:
- ivo://CDS.VizieR/J/MNRAS/467/1414
- Title:
- Radial velocity changes for 439 white dwarfs
- Short Name:
- J/MNRAS/467/1414
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- From a sample of spectra of 439 white dwarfs (WDs) from the ESO-VLT Supernova-Ia Progenitor Survey (SPY), we measure the maximal changes in radial velocity ({Delta}RVmax) between epochs (generally two epochs, separated by up to 470d), and model the observed {Delta}RVmax statistics via Monte Carlo simulations, to constrain the population characteristics of double WDs (DWDs). The DWD fraction among WDs is f_bin_=0.10+/-0.02 (1{sigma}, random) +0.02 (systematic), in the separation range <~4au within which the data are sensitive to binarity. Assuming the distribution of binary separation, a, is a power law, dN/da{prop.to}a^alpha^, at the end of the last common-envelope phase and the start of solely gravitational-wave-driven binary evolution, the constraint by the data is alpha=-1.3+/-0.2(1{sigma}) +/-0.2 (systematic). If these parameters extend to small separations, the implied Galactic WD merger rate per unit stellar mass is R_merge_=(1-80)x10^-13^yr^-1^M_[sun}_^-1^ (2{sigma}), with a likelihood-weighted mean of R_merge_=(7+/-2)x10^-13^yr^-1^M_{sun}_^-1^ (1{sigma}). The Milky Way's specific Type Ia supernova (SN Ia) rate is likely R_Ia_~=1.1x10^-13^yr^-1^M_{sun}_^-1^ and therefore, in terms of rates, a possibly small fraction of all merging DWDs (e.g. those with massive-enough primary WDs) could suffice to produce most or all SNe Ia.
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Search Results
- ID:
- ivo://CDS.VizieR/J/AJ/156/82
- Title:
- Radial velocity characterization of TESS planets
- Short Name:
- J/AJ/156/82
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The Transiting Exoplanet Survey Satellite (TESS) will conduct a two-year wide-field survey searching for transiting planets around bright stars. Many TESS discoveries will be amenable to mass characterization via ground-based radial velocity measurements with any of a growing suite of existing and anticipated velocimeters in the optical and near-infrared. In this study we present an analytical formalism to compute the number of radial velocity (RV) measurements - and hence the total observing time-required to characterize RV planet masses with the inclusion of either a white or correlated noise activity model. We use our model to calculate the total observing time required to measure all TESS planet masses from the expected TESS planet yield while relying on our current understanding of the targeted stars, stellar activity, and populations of unseen planets that inform the expected RV precision. We also present specialized calculations applicable to a variety of interesting subsets of TESS planets including the characterization of 50 planets smaller than 4 Earth radii, which is expected to take as little as 60 nights of observation. However, the efficient RV characterization of such planets requires a priori knowledge of the "best" targets, which we argue can be identified prior to the conclusion of the TESS planet search based on our calculations. Our results highlight the comparable performance of optical and near-IR spectrographs for most planet populations except for Earths and temperate TESS planets, which are more efficiently characterized in the near-IR. Lastly, we present an online tool to the community to compute the total observing times required to detect any transiting planet using a user-defined spectrograph (RVFC; http://maestria.astro.umontreal.ca/rvfc).
- ID:
- ivo://CDS.VizieR/J/A+A/610/A3
- Title:
- Radial velocity curve of 3 K giants
- Short Name:
- J/A+A/610/A3
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The purpose of this paper is to detect and investigate the nature of long-term radial velocity (RV) variations of K-type giants and to confirm planetary companions around the stars. We have conducted two planet search programs by precise RV measurement using the 1.8m telescope at Bohyunsan Optical Astronomy Observatory (BOAO) and the 1.88m telescope at Okayama Astrophysical Observatory (OAO). The BOAO program searches for planets around 55 early K giants. The OAO program is looking for 190 G-K type giants. In this paper, we report the detection of long-period RV variations of three K giant stars, HD 40956, HD 111591, and HD 113996. We investigated the cause of the observed RV variations and conclude the substellar companions are most likely the cause of the RV variations. The orbital analyses yield P=578.6+/-3.3d, msini=2.7+/-0.6M_J_, a=1.4+/-0.1AU for HD 40956; P=1056.4+/-14.3d, msini=4.4+/-0.4M_J_, a=2.5+/-0.1AU for HD 111591; P=610.2+/-3.8d, msini=6.3+/-1.0M_J_, a=1.6+/-0.1AU for HD 113996.
- 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+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/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/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/AJ/148/118
- Title:
- Radial velocity curves of LMC ellipsoidal variables
- Short Name:
- J/AJ/148/118
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Ellipsoidal red giant binaries are close binary systems where an unseen, relatively close companion distorts the red giant, leading to light variations as the red giant moves around its orbit. These binaries are likely to be the immediate evolutionary precursors of close binary planetary nebula and post-asymptotic giant branch and post-red giant branch stars. Due to the MACHO and OGLE photometric monitoring projects, the light variability nature of these ellipsoidal variables has been well studied. However, due to the lack of radial velocity curves, the nature of their masses, separations, and other orbital details has so far remained largely unknown. In order to improve this situation, we have carried out spectral monitoring observations of a large sample of 80 ellipsoidal variables in the Large Magellanic Cloud and we have derived radial velocity curves. At least 12 radial velocity points with good quality were obtained for most of the ellipsoidal variables. The radial velocity data are provided with this paper. Combining the photometric and radial velocity data, we present some statistical results related to the binary properties of these ellipsoidal variables.
- ID:
- ivo://CDS.VizieR/J/A+A/648/A58
- Title:
- Radial velocity curves of 4 stars
- Short Name:
- J/A+A/648/A58
- Date:
- 07 Dec 2021 08:07:13
- Publisher:
- CDS
- Description:
- We present the current status of and new results from our search for exoplanets in a sample of solar-mass evolved stars observed with the HARPS-N and the 3.6m Telescopio Nazionale Galileo (TNG), and the High-Resolution Spectrograph (HRS) and the 9.2m Hobby-Eberly Telescope (HET). The aim of this project is to detect and characterize planetary-mass companions to solar-mass stars in a sample of 122 targets at various stages of evolution from the main sequence (MS) to the red giant branch (RGB), mostly subgiants and giants, selected from the Pennsylvania-Torun Planet Search (PTPS) sample, and to use this sample to study relations between stellar properties, such as metallicity, luminosity, and the planet occurrence rate. This work is based on precise radial velocity (RV) measurements. We have observed the program stars for up to 14 years with the HET/HRS and the TNG/HARPS-N. We present the analysis of RV measurements with the HET/HRS and the TNG/HARPS-N of four solar-mass stars, HD 4760, HD 96992 , BD+02 3313, and TYC 0434-04538-1. We found that HD 4760 hosts a companion with a minimum mass of 13.9M_J_) (a=1.14au, e=0.23); HD 96992 is a host to a msini=1.14M_J_ companion on an a=1.24au and e=0/41 orbit, and TYC 0434-04538-1 hosts an msini=6.1M_J_ companion on an a=0.66au and e=0.08 orbit. In the case of BD+02 3313 we found a correlation between the measured RVs and one of the stellar activity indicators, suggesting that the observed RV variations may either originate in stellar activity or be caused by the presence of an unresolved companion. We also discuss the current status of the project and a statistical analysis of the RV variations in our sample of target stars. In our sample of 122 solar-mass stars, 49+/-5% of them appear to be single and 16+/-3% spectroscopic binaries. The three giants hosting low-mass companions presented in this paper join the six previously identified giants in the sample.
- ID:
- ivo://CDS.VizieR/J/AJ/161/283
- Title:
- Radial velocity estimates of 4 stars with IGRINS
- Short Name:
- J/AJ/161/283
- Date:
- 08 Mar 2022
- Publisher:
- CDS
- Description:
- Application of the radial velocity (RV) technique in the near-infrared is valuable because of the diminished impact of stellar activity at longer wavelengths, making it particularly advantageous for the study of late-type stars but also for solar-type objects. In this paper, we present the IGRINS RV open-source python pipeline for computing infrared RV measurements from reduced spectra taken with IGRINS, an R~{lambda}/{Delta}{lambda}~45000 spectrograph with simultaneous coverage of the H-band (1.49-1.80{mu}m) and K-band (1.96-2.46{mu}m). Using a modified forward-modeling technique, we construct high-resolution telluric templates from A0 standard observations on a nightly basis to provide a source of common-path wavelength calibration while mitigating the need to mask or correct for telluric absorption. Telluric standard observations are also used to model the variations in instrumental resolution across the detector, including a yearlong period when the K-band was defocused. Without any additional instrument hardware, such as a gas cell or laser frequency comb, we are able to achieve precisions of 26.8m/s in the K-band and 31.1m/s in the H-band for narrow-line hosts. These precisions are empirically determined by a monitoring campaign of two RV standard stars, as well as the successful retrieval of planet-induced RV signals for both HD189733 and {tau}BooA; furthermore, our results affirm the presence of the Rossiter-McLaughlin effect for HD189733. The IGRINS RV pipeline extends another important science capability to IGRINS, with publicly available software designed for widespread use.
