- ID:
- ivo://CDS.VizieR/J/A+A/572/A50
- Title:
- J0113+31 light + velocity curves
- Short Name:
- J/A+A/572/A50
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We derive the fundamental properties of 1SWASP J011351.29+314909.7 (J0113+31), a metal-poor (-0.40+/-0.04dex), eclipsing binary in an eccentric orbit (~0.3) with an orbital period of 14.277d. Eclipsing M dwarfs that orbit solar-type stars (EBLMs), like J0113+31, have been identified from their light curves and follow-up spectroscopy in the course of the WASP transiting planet search. We present the analysis of the first binary of the EBLM sample for which masses, radii and temperatures of both components are derived. The primary component with a mass of 0.945+/-0.045M_{sun}_ has a large radius (1.378+/-0.058R_{sun}_) indicating that the system is quite old, ~9.5Gyr. The M-dwarf secondary mass of 0.186+/-0.010M_{sun}_ and radius of 0.209+/-0.011R_{sun}_ are fully consistent with stellar evolutionary models. However, from the near-infrared secondary eclipse light curve, the M dwarf is found to have an effective temperature of 3922+/-42K, which is ~600K hotter than predicted by theoretical models. We present the WASP light curve, the optical follow-up light curves, the near-infrared light curve of the secondary eclipse, and the radial velocity measurements of J0113+31.
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Search Results
- ID:
- ivo://CDS.VizieR/J/A+A/446/583
- Title:
- Journal of all RVs of eps Per primary
- Short Name:
- J/A+A/446/583
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- A detailed analysis of a large collection of electronic spectra from three observatories, together with radial velocities published earlier, were used to derive a new ephemeris and improved orbital elements for the eps Per binary. Observations covering a time interval of about 37000-days (101.3-years) can be reconciled with a constant orbital period of (14.0691+/-0.00004)-days. The high orbital eccentricity of 0.555+/-0.009 was also confirmed. New spectral observations confirm that there is a periodic variation of the systemic velocity. Together with new evidence from astrometric observations (also analyzed here), they confirm the existence of a third body in the system with an orbital period of about 9600-days (26.3-years), rather than 4156-days, as reported earlier. Application of the disentangling technique to the H alpha spectra with good S/N ratios did not allow detection of spectral lines of either the secondary or tertiary components. For plausible inclinations between 30 and 90 {deg}, the observed mass function implies a mass of the secondary M_2_=0.85-1.77M_{sun}_, if a primary mass is adopted of (13.5+/-2.0)M_{sun}_. Attempts to detect the third body via interferometric observations should continue in spite of this first negative result.
- ID:
- ivo://CDS.VizieR/J/A+A/554/A74
- Title:
- Jupiter's zonal winds in 2011
- Short Name:
- J/A+A/554/A74
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The general circulation of Jupiter's atmosphere at cloud level is dominated by a system of zonal jets that alternate in direction with latitude. The winds, measured in high-resolution images obtained by different space missions and the Hubble Space Telescope, are overall stable in their latitude location with small changes in intensity at particular jets. However, the atmosphere experiences repetitive changes in the albedo of particular belts and zones that are subject to large-scale intense disturbances that may locally influence the profile. The lack of high-resolution images has not allowed the wind system to be studied with the regularity required to assess its stability with respect to these major changes or to other types of variations (e.g., seasonality). To amend that, we present a study of the zonal wind profile of Jupiter using images acquired around the 2011 opposition by a network of observers operating small-size telescopes with apertures in the range 0.20-1m. Using an automatic correlation technique, we demonstrate the capability to extract the mean zonal winds in observing periods close to the opposition. A broad collaboration with skilled amateur astronomers opens the possibility to regularly study short- and long-term changes in the jets of Jupiter. We compare the 2011 Jovian wind profile to those previously obtained. The winds did not experience significant short-term changes over 2011 but show noteworthy variations at particular latitudes when compared with wind profiles from previous years. Most of these variations are related to major changes in the cloud morphology of the planet, in particular at 7{deg}N where an intense eastward jet varies around 40m/s in its intensity according to the development or not of the "dark projection" features, confirming previous results.
754. Jurassic structure
- ID:
- ivo://CDS.VizieR/J/A+A/644/A83
- Title:
- Jurassic structure
- Short Name:
- J/A+A/644/A83
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Detailed elemental-abundance patterns of giant stars in the Galactic halo measured by the Apache Point Observatory Galactic Evolution Experiment (APOGEE-2) have revealed the existence of a unique and significant stellar subpopulation of silicon-enhanced ([Si/Fe]>+0.5) metal-poor stars, spanning a wide range of metallicities (-1.5<[Fe/H]<-0.8). Stars with over-abundances in [Si/Fe] are of great interest because these have very strong silicon (^28^Si) spectral features for stars of their metallicity and evolutionary stage, offering clues about rare nucleosynthetic pathways in globular clusters (GCs). Si-rich field stars have been conjectured to have been evaporated from GCs, however, the origin of their abundances remains unclear, and several scenarios have been offered to explain the anomalous abundance ratios. These include the hypothesis that some of them were born from a cloud of gas previously polluted by a progenitor that underwent a specific and peculiar nucleosynthesis event or, alternatively, that they were due to mass transfer from a previous evolved companion. However, those scenarios do not simultaneously explain the wide gamut of chemical species that are found in Si-rich stars. Instead, we show that the present inventory of such unusual stars, as well as their relation to known halo substructures (including the in situ halo, Gaia-Enceladus, the Helmi Stream(s), and Sequoia, among others), is still incomplete. We report the chemical abundances of the iron-peak (Fe), the light- (C and N), the alpha- (O and Mg), the odd-Z (Na and Al), and the s-process (Ce and Nd) elements of 55 newly identified Si-rich field stars (among more than ~600000 APOGEE-2 targets), which exhibit over-abundances of [Si/Fe] as extreme as those observed in some Galactic GCs, and they are relatively well distinguished from other stars in the [Si/Fe]-[Fe/H] plane. This new census confirms the presence of a statistically significant and chemically-anomalous structure in the inner halo: Jurassic. The chemo-dynamical properties of the Jurassic structure is consistent with it being the tidally disrupted remains of GCs, which are easily distinguished by an over-abundance of [Si/Fe] among Milky Way (MW) populations or satellites.
- ID:
- ivo://CDS.VizieR/J/A+A/597/A52
- Title:
- K and G dwarfs stellar granulation variability
- Short Name:
- J/A+A/597/A52
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- In solar-type stars, the attenuation of convective blueshift by stellar magnetic activity dominates the RV (radial velocity) variations over the low amplitude signal induced by low mass planets. Models of stars that differ from the Sun will require a good knowledge of the attenuation of the convective blueshift to estimate its impact on the variations. It is therefore crucial to precisely determine not only the amplitude of the convective blueshift for different types of stars, but also the dependence of this convective blueshift on magnetic activity, as these are key factors in our model producing the RV. We studied a sample of main sequence stars with spectral types from G0 to K2 and focused on their temporally averaged properties: the activity level and a criterion allowing to characterise the amplitude of the convective blueshift. This criterion is derived from the dependence of the convective blueshift with the intensity at the bottom of a large set of selected spectral lines.
- ID:
- ivo://CDS.VizieR/J/A+A/640/A48
- Title:
- K2-32 and K2-233 light and RV curves
- Short Name:
- J/A+A/640/A48
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- High-precision planetary densities are key pieces of information necessary to derive robust atmospheric properties for extrasolar planets. Measuring precise masses is the most challenging part of this task, especially in multi-planetary systems. The ESO-K2 collaboration focuses on the follow-up of a selection of multi-planetary systems detected by the K2 mission using the HARPS instrument with this goal in mind. In this work, we measure the masses and densities of two multi-planetary systems: a four-planet near resonant chain system (K2-32) and a young (~400Myr old) planetary system consisting of three close-in small planets (K2-233). We obtained 199 new HARPS observations for K2-32 and 124 for K2-233 covering a long baseline of more than three years. We performed a joint analysis of the radial velocities and K2 photometry with PASTIS to precisely measure and constrained the properties of these planets, focusing on their masses and orbital properties. We find that K2-32 is a compact scaled-down version of the Solar System's architecture, with a small rocky inner planet (Me=2.1_-1.1_^+1.3^M_{earth}_, Pe~4.35-days) followed by an inflated Neptune-mass planet (Mb=15.0_-1.7_^+1.8^M_{earth}_, Pb~8.99-days) and two external sub-Neptunes (Mc=8.1+/-2.4M_{earth}_, Pc~20.66-days; Md=6.7+/-2.5M_{earth}_, Pd~31.72-days). K2-32 becomes one of the few multi-planetary systems with four or more planets known where all have measured masses and radii. Additionally, we constrain the masses of the three planets in the K2-233 system through marginal detection of their induced radial velocity variations. For the two inner Earth-size planets we constrain their masses at a 95% confidence level to be smaller than Mb<11.3M_{earth}_ (Pb~2.47-days), Mc<12.8M_{earth}_ (Pc~7.06-days). The outer planet is a sub-Neptune size planet with an inferred mass of Md=8.3_-4.7_^+5.2^M_{earth}_ (Md<21.1M_{earth}_, Pd~24.36-days). Our observations of these two planetary systems confirm for the first time the rocky nature of two planets orbiting a young star, with relatively short orbital periods (<7-days). They provide key information for planet formation and evolution models of telluric planets. Additionally, the Neptune-like derived masses of the three planets, K2-32 b, c, d, puts them in a relatively unexplored regime of incident flux and planet mass, which is key for transmission spectroscopy studies in the near future.
- ID:
- ivo://CDS.VizieR/J/MNRAS/499/5004
- Title:
- K2-111, an old system with two planets
- Short Name:
- J/MNRAS/499/5004
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- This paper reports on the detailed characterisation of the K2-111 planetary system with K2, WASP, and ASAS-SN photometry as well as high-resolution spectroscopic data from HARPS-N and ESPRESSO. The host, K2-111, is confirmed to be a mildly evolved (logg=4.17), iron-poor ([Fe/H]=-0.46), but alpha-enhanced ([{alpha}/Fe]=0.27), chromospherically quiet, very old thick disc G2 star. A global fit, performed by using PyORBIT shows that the transiting planet, K2-111 b, orbits with a period P_b_=5.3518+/-0.0004d, and has a planet radius of 1.82^+0.11^_-0.09_R_{Earth}_ and a mass of 5.29^+0.76^_-0.77_ M_{Earth}_, resulting in a bulk density slightly lower than that of the Earth. The stellar chemical composition and the planet properties are consistent with K2-111 b being a terrestrial planet with an iron core mass fraction lower than the Earth. We announce the existence of a second signal in the radial velocity data that we attribute to a non-transiting planet, K2-111 c, with an orbital period of 15.6785+/-0.0064 days, orbiting in near-3:1 mean-motion resonance with the transiting planet, and a minimum planet mass of 11.3+/-1.1 M_{Earth}_. Both planet signals are independently detected in the HARPS-N and ESPRESSO data when fitted separately. There are potentially more planets in this resonant system, but more well-sampled data are required to confirm their presence and physical parameters.
- ID:
- ivo://CDS.VizieR/J/ApJ/636/1020
- Title:
- kappa Peg astrometry and radial velocities
- Short Name:
- J/ApJ/636/1020
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- {kappa} Pegasi is a well-known, nearby triple star system. It consists of a "wide" pair with semimajor axis =235mas, one component of which is a single-line spectroscopic binary (semimajor axis =2.5mas). Using high-precision differential astrometry and radial velocity observations, the masses for all three components are determined and the relative inclination between the wide and narrow pairs' orbits is found to be 43.8{deg}+/-3.0{deg}, just over the threshold for the three-body Kozai resonance. The system distance is determined to be 34.60+/-0.21pc and is consistent with trigonometric parallax measurements.
- ID:
- ivo://CDS.VizieR/J/ApJ/808/103
- Title:
- Kapteyn moving group star abundances
- Short Name:
- J/ApJ/808/103
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The Kapteyn moving group has been postulated as tidal debris from {omega} Centauri. If true, members of the group should show some of the chemical abundance patterns known for stars in the cluster. We present an optical and near-infrared high-resolution, high-signal-to-noise ratio spectroscopic study of 14 stars of the Kapteyn group, plus 10 additional stars (the {omega} Cen group) that, while not listed as members of the Kapteyn group as originally defined, have nevertheless been associated dynamically with {omega} Centauri. Abundances for Na, O, Mg, Al, Ca, and Ba were derived from the optical spectra, while the strength of the chromospheric HeI10830{AA} line is studied as a possible helium abundance indicator. The resulting Na-O and Mg-Al patterns for stars of the combined Kapteyn and {omega} Cen group samples do not resemble those of {omega} Centauri, and are not different from those of field stars of the Galactic halo. The distribution of equivalent widths of the HeI10830{AA} line is consistent with that found among non-active field stars. Therefore, no evidence is found for second-generation stars within our samples, which most likely rules out a globular-cluster origin. Moreover, no hint of the unique barium overabundance at the metal-rich end, well established for {omega} Centauri stars, is seen among stars of the combined samples. Because this specific Ba pattern is present in {omega} Centauri irrespective of stellar generation, this would rule out the possibility that our entire sample might be composed of only first-generation stars from the cluster. Finally, for the stars of the Kapteyn group, the possibility of an origin in the hypothetical parent galaxy of {omega} Centauri is disfavored by the different run of {alpha}-elements with metallicity between our targets and stars from present-day dwarf galaxies.
- ID:
- ivo://CDS.VizieR/J/MNRAS/443/L89
- Title:
- Kapteyn's star spectroscopic measurements
- Short Name:
- J/MNRAS/443/L89
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Exoplanets of a few Earth masses can be now detected around nearby low-mass stars using Doppler spectroscopy. In this paper, we investigate the radial velocity variations of Kapteyn's star, which is both a sub-dwarf M-star and the nearest halo object to the Sun. The observations comprise archival and new HARPS, HIRES and PFS Doppler measurements. Two Doppler signals are detected at periods of 48 and 120 days using likelihood periodograms and a Bayesian analysis of the data. Using the same techniques, the activity indices and archival ASAS-3 photometry show evidence for low-level activity periodicities of the order of several hundred days. However, there are no significant correlations with the radial velocity variations on the same time-scales. The inclusion of planetary Keplerian signals in the model results in levels of correlated and excess white noise that are remarkably low compared to younger G, K and M dwarfs. We conclude that Kapteyn's star is most probably orbited by two super-Earth mass planets, one of which is orbiting in its circumstellar habitable zone, becoming the oldest potentially habitable planet known to date. The presence and long-term survival of a planetary system seems a remarkable feat given the peculiar origin and kinematic history of Kapteyn's star. The detection of super-Earth mass planets around halo stars provides important insights into planet-formation processes in the early days of the Milky Way.
