- ID:
- ivo://CDS.VizieR/J/A+A/546/A10
- Title:
- Multiplicity in transiting planet-host stars
- Short Name:
- J/A+A/546/A10
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- In the exoplanetary era, the Kepler spacecraft is causing a revolution by discovering thousands of new planet candidates. However, a follow-up program is needed to reject false candidates and fully characterize the bona-fide exoplanets. Our main aims are to 1./ detect and analyze close companions inside the typical Kepler point spread function (PSF) to study whether they are the responsible for the dimming found in Kepler light curves, 2./ study the change in the stellar and planetary parameters caused by an unresolved object, 3./ help validate the Kepler objects of interest (KOI) that do not have any object inside the Kepler PSF, and 4./ study the multiplicity rate of planet-host candidates. Such a large sample of observed planet-host candidates allows us to derive statistics for close (visual or bounded) companions to the harboring star.
Number of results to display per page
Search Results
- ID:
- ivo://CDS.VizieR/J/AJ/131/2986
- Title:
- Multiplicity of contact binaries
- Short Name:
- J/AJ/131/2986
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We have attempted to establish observational evidence for the presence of distant companions that may have acquired and/or absorbed angular momentum during the evolution of multiple systems, thus facilitating or enabling the formation of contact binaries. In this preliminary investigation we use several techniques (some of them distance- independent) and mostly disregard the detection biases of individual techniques in an attempt to establish a lower limit to the frequency of triple systems. While the whole sample of 151 contact binary stars brighter than V_max_=10mag gives a firm lower limit of 42%{+/-}5%, the corresponding number for the much better observed northern-sky subsample is 59%{+/-}8%. These estimates indicate that most contact binary stars exist in multiple systems.
- ID:
- ivo://CDS.VizieR/J/AJ/154/184
- Title:
- Multiplicity of RV exoplanet host stars
- Short Name:
- J/AJ/154/184
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Given the frequency of stellar multiplicity in the solar neighborhood, it is important to study the impacts this can have on exoplanet properties and orbital dynamics. There have been numerous imaging survey projects established to detect possible low-mass stellar companions to exoplanet host stars. Here, we provide the results from a systematic speckle imaging survey of known exoplanet host stars. In total, 71 stars were observed at 692 and 880 nm bands using the Differential Speckle Survey Instrument at the Gemini-north Observatory. Our results show that all but two of the stars included in this sample have no evidence of stellar companions with luminosities down to the detection and projected separation limits of our instrumentation. The mass-luminosity relationship is used to estimate the maximum mass a stellar companion can have without being detected. These results are used to discuss the potential for further radial velocity follow-up and interpretation of companion signals.
- ID:
- ivo://CDS.VizieR/J/A+A/635/A73
- Title:
- Multiplicity study of transiting exoplanet hosts. I.
- Short Name:
- J/A+A/635/A73
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Many main-sequence stars are part of multiple systems. The effect of stellar multiplicity on planet formation and migration, however, is poorly understood. We study the multiplicity of stars hosting known transiting extra-solar planets to test competing theories on the formation mechanisms of hot Jupiters. We observed 45 exoplanet host stars using the infrared dual imaging spectrograph (IRDIS) of the Spectro-Polarimetric High-Contrast Exoplanet Research (SPHERE) instrument at the Very Large Telescope (VLT) to search for potential companions. For each identified candidate companion we determined the probability that it is gravitationally bound to its host by performing common proper motion checks and modelling of synthetic stellar populations around the host. In addition, we derived contrast limits as a function of angular separation to set upper limits on further companions in these systems. We converted the derived contrast into mass thresholds using AMES-Cond, AMES-Dusty, and BT-Settl models. We detected new candidate companions around K2-38, WASP-72, WASP-80, WASP-87, WASP-88, WASP-108, WASP-118, WASP-120, WASP-122, WASP123, WASP-130, WASP-131, and WASP-137. The closest candidates were detected at separations of 0.124"+/-0.007" and 0.189"+/-0.003" around WASP-108 and WASP-131; the measured K-band contrasts indicate that these are stellar companions of 0.35+/-0.02M_{sun}_ and 0.62^+0.05^_-0.04_M_{sun}_, respectively. Including the re-detection and confirmation of previously known companions in 13 other systems, we derived a multiplicity fraction of 55.4^+5.9^_-9.4_%. For the representative sub-sample of 40 hot Jupiter host stars among our targets, the derived multiplicity rate is 54.8^+6.3^_-9.9_%. Our data do not confirm any trend that systems with eccentric planetary companions are preferably part of multiple systems. On average, we reached a magnitude contrast of 8.5+/-0.9,mag at an angular separation of 0.5". This allows us to exclude additional stellar companions with masses higher than 0.08M_{sun}_ for almost all observed systems; around the closest and youngest systems, this sensitivity is achieved at physical separations as small as 10au. Our study shows that SPHERE is an ideal instrument for detecting and characterising close companions to exoplanetary host stars.Although the second data release of the Gaia mission also provides useful constraints for some of the systems, the achieved sensitivity provided by the current data release of this mission is not good enough to measure parallaxes and proper motions for all detected candidates. For 14 identified companion candidates further astrometric epochs are required to confirm their common proper motion at 5{sigma} significance.
- ID:
- ivo://CDS.VizieR/J/A+A/632/A3
- Title:
- MUSE binaries in NGC 3201
- Short Name:
- J/A+A/632/A3
- Date:
- 09 Feb 2022 07:38:27
- Publisher:
- CDS
- Description:
- We utilize multi-epoch MUSE spectroscopy to study binaries in the core of NGC 3201. Our sample consists of 3553 stars with 54883 spectra in total comprising 3200 main-sequence stars up to 4 magnitudes below the turn-off. Each star in our sample has between 3 and 63 (with a median of 14) reliable radial velocity (RV) measurements within five years of observations. We introduce a statistical method to determine the probability of a star showing RV variations based on the whole inhomogeneous RV sample. Using HST photometry and an advanced dynamical MOCCA simulation of this specific GC we overcome observational biases that previous spectroscopic studies had to deal with. This allows us to infer a binary frequency in the MUSE FoV and enables us to deduce the underlying true binary frequency of (6.75+/-0.72)% in NGC 3201. The comparison of the MUSE observations with the MOCCA simulation suggests a significant fraction of primordial binaries. We can also confirm a radial increase of the binary fraction towards the GC centre due to mass segregation. We discovered that in our sample at least (57.5+/-7.9)% of blue straggler stars (BSS) are in a binary system. For the first time in a study of GCs, we were able to fit Keplerian orbits to a significant sample of 95 binaries. We present the binary system properties of eleven BSS and show evidence that two BSS formation scenarios, the mass transfer in binary (or triple) star systems and the coalescence due to binary-binary interactions, are present in our data. We also describe the binary and spectroscopic properties of four sub-subgiant (or red straggler) stars. Furthermore, we discovered two new black hole (BH) candidates with minimum masses (Msini) of (7.68+/-0.50)M_{sun}_, (4.4+/-2.8)M_{sun}_, and refine the minimum mass estimate on the already published BH to (4.53+/-0.21)M_{sun}_. These BHs are consistent with an extensive BH subsystem hosted by NGC 3201.
- ID:
- ivo://CDS.VizieR/J/ApJ/789/10
- Title:
- M33 WR and Of-type Stars
- Short Name:
- J/ApJ/789/10
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Massive star evolutionary models generally predict the correct ratio of WC-type and WN-type Wolf-Rayet stars at low metallicities, but underestimate the ratio at higher (solar and above) metallicities. One possible explanation for this failure is perhaps single-star models are not sufficient and Roche-lobe overflow in close binaries is necessary to produce the "extra" WC stars at higher metallicities. However, this would require the frequency of close massive binaries to be metallicity dependent. Here we test this hypothesis by searching for close Wolf-Rayet binaries in the high metallicity environments of M31 and the center of M33 as well as in the lower metallicity environments of the middle and outer regions of M33. After identifying ~100 Wolf-Rayet binaries based on radial velocity variations, we conclude that the close binary frequency of Wolf-Rayets is not metallicity dependent and thus other factors must be responsible for the overabundance of WC stars at high metallicities. However, our initial identifications and observations of these close binaries have already been put to good use as we are currently observing additional epochs for eventual orbit and mass determinations.
- ID:
- ivo://CDS.VizieR/J/AJ/142/73
- Title:
- NAO Rozhen CCD measurements of multiple stars
- Short Name:
- J/AJ/142/73
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Using the 2m telescope of the Bulgarian National Astronomical Observatory at Rozhen, observations of 145 double or multiple stars were carried out during three nights on 2010 September 7-9. This is the fifth series of measurements of CCD frames of double and multiple stars obtained at Rozhen. In this paper, we present the results for the position angle and angular separation for 202 pairs and residuals for 45 pairs with published orbital elements or linear solutions. These observations have angular separations in the range 1.150"-196.372", with a median angular separation of 57.906". Three linear solutions are presented for the first time and three orbits are recalculated (one pair has both a linear fit and an orbital solution).
- ID:
- ivo://CDS.VizieR/J/MNRAS/457/2192
- Title:
- NCJM catalog of M dwarfs
- Short Name:
- J/MNRAS/457/2192
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We develop a method to identify the spectroscopic signature of unresolved L-dwarf ultracool companions, which compares the spectra of candidates and their associated control stars using spectral ratio differences and residual spectra. We present SpeX prism-mode spectra (0.7-2.5 micron) for a pilot sample of one hundred and eleven mid M dwarfs, including twenty-eight which were previously identified as candidates for unresolved ultracool companionship (a sub-sample from Cook et al. 2016; paper 1) and eighty-three single M dwarfs which were optically colour-similar to these candidates (which we use as `control stars'). We identify four candidates with evidence for near-infrared excess. One of these (WISE J100202.50+074136.3) shows strong evidence for an unresolved L dwarf companion in both its spectral ratio difference and its residual spectra, two most likely have a different source for the near-infrared excess, and the other may be due to spectral noise. We also establish expectations for a null result (i.e. by searching for companionship signatures around the M dwarf control stars), as well as determining the expected outcome for ubiquitous companionship (as a means of comparison with our actual results), using artificially generated unresolved M+L dwarf spectra. The results of these analyses are compared to those for the candidate sample, and reasonable consistency is found. With a full follow-up program of our candidates sample from paper 1, we might expect to confirm up to 40 such companions in the future, adding extensively to the known desert population of M3-M5 dwarfs.
- ID:
- ivo://CDS.VizieR/J/other/AstBu/68.53
- Title:
- Nearby multiple Speckle interferometry. V.
- Short Name:
- J/other/AstBu/68
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The results of speckle interferometric observations of 194 binary stars performed at the BTA 6m telescope in 2002-2006 are presented in this paper. For speckle observations we used filters with central wavelengths from 545 to 800nm and speckle camera with the fast CCD coupled with a tree-chamber intensifier. The most part of the observed systems (80 stars) - pairs, which binarity was discovered by Hipparcos satellite fo the first time. And the other stars are visual binaries and interferometric binary systems which orbital periods estimates from several to ten of the year. The pairs with slow orbital motion are included to the observation list, also. They are used for position parameters calibrations.
- ID:
- ivo://CDS.VizieR/J/A+A/422/627
- Title:
- Nearby multiple stars speckle interferometry
- Short Name:
- J/A+A/422/627
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- This paper is a continuation of diffraction-limited speckle interferometry of binary and multiple stars carried out at the 6-m telescope of the Special Astrophysical Observatory in Zelenchuk. The program has concentrated on nearby ({pi}>10mas) close binaries discovered or measured during the Hipparcos mission. Here, we present 132 measurements of relative positions and magnitude differences for 99 pairs and 8 measurements for 6 triple systems. 54 entries in the paper are new Hipparcos binaries. New triple systems with late-type dwarf components, discovered in the course of observations, are HIP 8533 and HIP 25354.
