- ID:
- ivo://CDS.VizieR/J/ApJ/821/52
- Title:
- NIR survey of Spitzer YSOs in Orion Mol. Cloud
- Short Name:
- J/ApJ/821/52
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a near-infrared survey for the visual multiples in the Orion molecular clouds region at separations between 100 and 1000au. These data were acquired at 1.6um with the NICMOS and WFC3 cameras on the Hubble Space Telescope. Additional photometry was obtained for some of the sources at 2.05um with NICMOS and in the L' band with NSFCAM2 on NASA's InfraRed Telescope Facility. Toward 129 protostars and 197 pre-main-sequence stars with disks observed with WFC3, we detect 21 and 28 candidate companions between the projected separations of 100-1000au, of which less than 5 and 8, respectively, are chance line-of-sight coincidences. The resulting companion fraction (CF) after the correction for the line-of-sight contamination is 14.4_-1.3_^+1.1^ for protostars and 12.5_-0.8_^+1.2^ for the pre-main-sequence stars. These values are similar to those found for main-sequence stars, suggesting that there is little variation in the CF with evolution, although several observational biases may mask a decrease in the CF from protostars to the main-sequence stars. After segregating the sample into two populations based on the surrounding surface density of young stellar objects, we find that the CF in the high stellar density regions ({Sigma}_YSO_>45pc^-2^) is approximately 50% higher than that found in the low stellar density regions ({Sigma}_YSO_<45pc^-2^). We interpret this as evidence for the elevated formation of companions at 100-1000 au in the denser environments of Orion. We discuss possible reasons for this elevated formation.
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- ID:
- ivo://CDS.VizieR/J/AJ/156/178
- Title:
- NIR transmission spectra of TRAPPIST-1 planets
- Short Name:
- J/AJ/156/178
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The seven approximately Earth-sized transiting planets in the TRAPPIST-1 system provide a unique opportunity to explore habitable- and nonhabitable-zone small planets within the same system. Its habitable-zone exoplanets - due to their favorable transit depths - are also worlds for which atmospheric transmission spectroscopy is within reach with the Hubble Space Telescope (HST) and James Webb Space Telescope (JWST). We present here an independent reduction and analysis of two HST Wide Field Camera 3 (WFC3) near-infrared transit spectroscopy data sets for six planets (b through g). Utilizing our physically motivated detector charge-trap correction and a custom cosmic-ray correction routine, we confirm the general shape of the transmission spectra presented by de Wit et al. (2016Natur.537...69D). Our data reduction approach leads to a 25% increase in the usable data and reduces the risk of confusing astrophysical brightness variations (e.g., flares) with instrumental systematics. No prominent absorption features are detected in any individual planet's transmission spectra; by contrast, the combined spectrum of the planets shows a suggestive decrease around 1.4 {mu}m similar to an inverted water absorption feature. Including transit depths from K2, the SPECULOOS-South Observatory, and Spitzer, we find that the complete transmission spectrum is fully consistent with stellar contamination owing to the transit light source effect. These spectra demonstrate how stellar contamination can overwhelm planetary absorption features in low-resolution exoplanet transit spectra obtained by HST and JWST and also highlight the challenges in combining multi-epoch observations for planets around rapidly rotating spotted stars.
- ID:
- ivo://CDS.VizieR/J/MNRAS/420/L23
- Title:
- Non-resonant Kepler planetary systems
- Short Name:
- J/MNRAS/420/L23
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The Kepler mission has discovered a plethora of multiple transiting planet candidate exosystems, many of which feature putative pairs of planets near mean motion resonance commensurabilities. Identifying potentially resonant systems could help guide future observations and enhance our understanding of planetary formation scenarios. We develop and apply an algebraic method to determine which Kepler two-planet systems cannot be in a first-fourth order resonance, given the current, publicly available data. This method identifies when any potentially resonant angle of a system must circulate. We identify and list 70 near-resonant systems which cannot actually reside in resonance, assuming a widely used formulation for deriving planetary masses from their observed radii and that these systems do not contain unseen bodies that affect the interactions of the observed planets. This work strengthens the argument that a high fraction of exoplanetary systems may be near resonance but not actually in resonance.
- ID:
- ivo://CDS.VizieR/J/A+A/576/A94
- Title:
- Northern bright planet host stars parameters
- Short Name:
- J/A+A/576/A94
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- In this work we derive new precise and homogeneous parameters for 37 stars with planets. For this purpose, we analyze high resolution spectra obtained by the NARVAL spectrograph for a sample composed of bright planet host stars in the northern hemisphere. The new parameters are included in the SWEET-Cat online catalogue. To ensure that the catalogue is homogeneous, we use our standard spectroscopic analysis procedure, ARES + MOOG, to derive effective temperatures, surface gravities, and metallicities. These spectroscopic stellar parameters are then used as input to compute the stellar mass and radius, which are fundamental for the derivation of the planetary mass and radius.
- ID:
- ivo://CDS.VizieR/J/MNRAS/448/2890
- Title:
- Observation of six NSVS eclipsing binaries
- Short Name:
- J/MNRAS/448/2890
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We carried out photometric and low-resolution spectral observations of six eclipsing ultrashort-period binaries with main-sequence (MS)components. The light-curve solutions of the Rozhen observations show that all targets are overcontact systems. We found a well-defined empirical relation between period and semi-major axis for the short-period binaries and used it for estimation of the global parameters of the targets. Our results revealed that NSVS 925605 is quite an interesting target: (i) it is one of a few contact binaries with M components; (ii) it exhibits high activity (emission in the H{alpha} line, X-ray emission, large cool spots, non-Planck energy distribution); (iii) its components differ in temperature by 700 K. All the appearances of high magnetic activity and the huge fill-out factor (0.7) of NSVS 925605 may be a precursor of the predicted merging of close magnetic binaries. Another unusual binary is NSVS 2700153, which reveals considerable long-term variability.
- ID:
- ivo://CDS.VizieR/J/AJ/153/212
- Title:
- Observations of binary stars at the WIYN telescope
- Short Name:
- J/AJ/153/212
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We report on speckle observations of binary stars carried out at the WIYN Telescope over the period from 2010 September through 2012 February, providing relative astrometry for 2521 observations of 883 objects, 856 of which are double stars and 27 of which are triples. The separations measured span a range of 0.01-1.75 arcsec. Wavelengths of 562, 692, and 880 nm were used, and differential photometry at one or more of these wavelengths is presented in most cases. 66 components were resolved for the first time. We also estimate detection limits at 0.2 and 1.0 arcsec for high-quality observations in cases where no companion was seen, a total of 176 additional objects. Detection limits vary based on observing conditions and signal-to-noise ratio, but are approximately 4 mag at 0.2 arcsec and 6 mag at 1.0 arcsec on average. Analyzing the measurement precision of the data set, we find that the individual separations obtained have linear measurement uncertainties of approximately 2 mas, and photometry is uncertain to approximately 0.1 mag in general. This work provides fundamental, well-calibrated data for future orbit and mass determinations, and we present three first orbits and total mass estimates of nearby K-dwarf systems as examples of this potential.
- ID:
- ivo://CDS.VizieR/J/AJ/159/233
- Title:
- Observations of binary stars with the DSSI. IX.
- Short Name:
- J/AJ/159/233
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We report 370 measures of 170 components of binary and multiple-star systems, obtained from speckle imaging observations made with the Differential Speckle Survey Instrument (DSSI) at Lowell Observatory's Discovery Channel Telescope in 2015 through 2017. Of the systems studied, 147 are binary stars, 10 are seen as triple systems, and 1 quadruple system is measured. Seventy-six high-quality nondetections and 15 newly resolved components are presented in our observations. The uncertainty in relative astrometry appears to be similar to our previous work at Lowell, namely, linear measurement uncertainties of approximately 2mas, and the relative photometry appears to be uncertain at the 0.1-0.15mag level. Using these measures and those in the literature, we calculate six new visual orbits, including one for the Be star 66Oph and two combined spectroscopic-visual orbits. The latter two orbits, which are for HD22451 (YSC127) and HD185501 (YSC135), yield individual masses of the components at the level of 2% or better, and independent distance measures that in one case agrees with the value found in the Gaia DR2 and in the other disagrees at the 2{sigma} level. We find that HD22451 consists of an F6V+F7V pair with orbital period of 2401.1{+/-}3.2days and masses of 1.342{+/-}0.029 and 1.236{+/-}0.026M_{sun}_. For HD185501, both stars are G5 dwarfs that orbit one another with a period of 433.94{+/-}0.15days, and the masses are 0.898{+/-}0.012 and 0.876{+/-}0.012M_{sun}_. We discuss the details of both the new discoveries and the orbit objects.
- ID:
- ivo://CDS.VizieR/J/AJ/134/2353
- Title:
- Observations of contact binaries
- Short Name:
- J/AJ/134/2353
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present results of the Canada-France-Hawaii Telescope adaptive optics (AO) search for companions of a homogeneous group of contact binary stars, as a contribution to our attempts to prove the hypothesis that these binaries require a third star to become as close as observed.
- ID:
- ivo://CDS.VizieR/J/ApJS/105/475
- Title:
- Observations of double stars. XVII.
- Short Name:
- J/ApJS/105/475
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Micrometer observations of 722 doubles, including 14 new pairs, in 1994-1995 are tabulated, along with some orbits.
- ID:
- ivo://CDS.VizieR/J/ApJS/117/587
- Title:
- Observations of double stars. XVIII.
- Short Name:
- J/ApJS/117/587
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Micrometer observations of 1350 pairs in 1995-1997 are listed.