- ID:
- ivo://CDS.VizieR/J/A+A/503/601
- Title:
- HD 17156 transit photometry & radial velocities
- Short Name:
- J/A+A/503/601
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- To improve the parameters of the HD17156 system (peculiar due to the eccentric and long orbital period of its transiting planet) and constrain the presence of stellar companions. Photometric data were acquired for 4 transits, and high precision radial velocity measurements were simultaneously acquired with SARG at TNG for one transit. The template spectra of HD 17156 was used to derive effective temperature, gravity, and metallicity. A fit of the photometric and spectroscopic data was performed to measure the stellar and planetary radii, and the spin-orbit alignment. Planet orbital elements and ephemeris were derived from the fit. Near infrared adaptive optic images was acquired with ADOPT at TNG. We have found that the star has a radius of R_S_=1.44+/-0.03R_{sun}_ and the planet R_P_=1.02+/-0.08R_{jup}_ The transit ephemeris is T_c_=2454756.73134+/-0.00020+N*21.21663+/-0.00045 BJD. The analysis of the Rossiter-Mclaughlin effect shows that the system is spin orbit aligned with an angle Beta=4.8+/-5.3deg The analysis of high resolution images has not revealed any stellar companion with projected separation between 150 and 1000 AU from HD17156. Here we present the photometric data of the transits of HD 17156b.
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262. HD 80606 transits
- ID:
- ivo://CDS.VizieR/J/MNRAS/419/2233
- Title:
- HD 80606 transits
- Short Name:
- J/MNRAS/419/2233
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We report observations of HD 80606 using the 10.4-m Gran Telescopio Canarias and the Optical System for Imaging and low Resolution Integrated Spectroscopy (OSIRIS) tunable filter imager. We acquired very high precision, narrow-band photometry in four bandpasses around the KI absorption feature during the 2010 January transit of HD 80606b and during out-of-transit observations conducted in 2010 January and April. We obtained differential photometric precisions of ~2.08x10^-4^ for the in-transit flux ratio measured at 769.91nm, which probes the KI line core.
- ID:
- ivo://CDS.VizieR/J/A+A/561/A7
- Title:
- High-precision abundances for stars with planets
- Short Name:
- J/A+A/561/A7
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Elemental abundance studies of solar twin stars suggest that the solar chemical composition contains signatures of the formation of terrestrial planets in the solar system, namely small but significant depletions of the refractory elements. To test this hypothesis, we study stars which, compared to solar twins, have less massive convective envelopes (therefore increasing the amplitude of the predicted effect) or are, arguably, more likely to host planets (thus increasing the frequency of signature detections). We measure relative atmospheric parameters and elemental abundances of a late-F type dwarf sample (52 stars) and a sample of metal-rich solar analogs (59 stars). We detect refractory-element depletions with amplitudes up to about 0.15dex. The distribution of depletion amplitudes for stars known to host gas giant planets is not different from that of the rest of stars. The maximum amplitude of depletion increases with effective temperature from 5650K to 5950K, while it appears to be constant for warmer stars (up to 6300K). The depletions observed in solar twin stars have a maximum amplitude that is very similar to that seen here for both of our samples. Gas giant planet formation alone cannot explain the observed distributions of refractory-element depletions, leaving the formation of rocky material as a more likely explanation of our observations. More rocky material is necessary to explain the data of solar twins than metal-rich stars, and less for warm stars. However, the sizes of the stars' convective envelopes at the time of planet formation could be regulating these amplitudes. Our results could be explained if disk lifetimes were shorter in more massive stars, as independent observations indeed seem to suggest.
- ID:
- ivo://CDS.VizieR/J/ApJ/721/1829
- Title:
- High-precision transits of OGLE-TR-113b
- Short Name:
- J/ApJ/721/1829
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present six new transits of the hot Jupiter OGLE-TR-113b observed with MagIC on the Magellan Telescopes between 2007 January and 2009 May. We update the system parameters and revise the planetary radius to R_p_=1.084+/-0.029R_J_, where the error is dominated by stellar radius uncertainties. The new transit midtimes reveal no transit timing variations from a constant ephemeris of greater than 13+/-28s over two years, placing an upper limit of 1-2M_{earth}_ on the mass of any perturber in a 1:2 or 2:1 mean-motion resonance with OGLE-TR-113b. Combining the new transit epochs with five epochs published between 2002 and 2006, we find hints that the orbital period of the planet may not be constant, with the best fit indicating a decrease of dP/dt=-60+/-15ms/yr. If real, this change in period could result from either a long-period (more than eight years) timing variation due to a massive external perturber or more intriguingly from the orbital decay of the planet. The detection of a changing period is still tentative and requires additional observations, but if confirmed it would enable direct tests of tidal stability and dynamical models of close-in planets.
- ID:
- ivo://CDS.VizieR/J/A+A/589/A58
- Title:
- High-resolution imaging of TEP systems (HITEP)
- Short Name:
- J/A+A/589/A58
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Wide binaries are a potential pathway for the formation of hot Jupiters. The binary fraction among host stars is an important discriminator between competing formation theories, but has not been well characterised. Additionally, contaminating light from unresolved stars can significantly affect the accuracy of photometric and spectroscopic measurements in studies of transiting exoplanets. We observed 101 transiting exoplanet host systems in the Southern hemisphere in order to create a homogeneous catalogue of both bound companion stars and contaminating background stars, in an area of the sky where transiting exoplanetary systems have not been systematically searched for stellar companions. We investigate the binary fraction among the host stars in order to test theories for the formation of hot Jupiters. Lucky imaging observations from the Two Colour Instrument on the Danish 1.54m telescope at La Silla were used to search for previously unresolved stars at small angular separations. The separations and relative magnitudes of all detected stars were measured. For 12 candidate companions to 10 host stars, previous astrometric measurements were used to evaluate how likely the companions are to be physically associated. We provide measurements of 499 candidate companions within 20 arcseconds of our sample of 101 planet host stars. 51 candidates are located within 5 arcseconds of a host star, and we provide the first published measurements for 27 of these. Calibrations for the plate scale and colour performance of the Two Colour Instrument are presented. We find that the overall multiplicity rate of the host stars is 38+17%, consistent with the rate among solar-type stars in our sensitivity range, suggesting that planet formation does not preferentially occur in long period binaries compared to a random sample of field stars. Long period stellar companions (P>10yr) appear to occur independently of short period companions, and so the population of close-in stellar companions is unconstrained by our study.
- ID:
- ivo://CDS.VizieR/J/ApJ/723/954
- Title:
- HIRES radial velocities of GJ 581
- Short Name:
- J/ApJ/723/954
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present 11 years of HIRES precision radial velocities (RVs) of the nearby M3V star Gliese 581, combining our data set of 122 precision RVs with an existing published 4.3-year set of 119 HARPS precision RVs (Mayor et al., 2009, Cat. J/A+A/507/487). The velocity set now indicates six companions in Keplerian motion around this star. Differential photometry indicates a likely stellar rotation period of ~94 days and reveals no significant periodic variability at any of the Keplerian periods, supporting planetary orbital motion as the cause of all the RV variations. The estimated equilibrium temperature of the sixth planet, GJ 581g, is 228K, placing it squarely in the middle of the habitable zone of the star and offering a very compelling case for a potentially habitable planet around a very nearby star. This detection, coupled with statistics of the incompleteness of present-day precision RV surveys for volume-limited samples of stars in the immediate solar neighborhood, suggests that {eta}_{oplus}_, the fraction of stars with potentially habitable planets, could well be on the order of a few tens of percent.
- ID:
- ivo://CDS.VizieR/J/ApJ/785/126
- Title:
- HIRES radial velocity measurements
- Short Name:
- J/ApJ/785/126
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- In this paper we search for distant massive companions to known transiting gas giant planets that may have influenced the dynamical evolution of these systems. We present new radial velocity observations for a sample of 51 planets obtained using the Keck HIRES instrument, and find statistically significant accelerations in fifteen systems. Six of these systems have no previously reported accelerations in the published literature: HAT-P-10, HAT-P-22, HAT-P-29, HAT-P-32, WASP-10, and XO-2. We combine our radial velocity fits with Keck NIRC2 adaptive optics (AO) imaging data to place constraints on the allowed masses and orbital periods of the companions responsible for the detected accelerations. The estimated masses of the companions range between 1-500 M_Jup_, with orbital semi-major axes typically between 1-75 AU. A significant majority of the companions detected by our survey are constrained to have minimum masses comparable to or larger than those of the transiting planets in these systems, making them candidates for influencing the orbital evolution of the inner gas giant. We estimate a total occurrence rate of 51%+/-10% for companions with masses between 1-13 M_Jup_ and orbital semi-major axes between 1-20 AU in our sample. We find no statistically significant difference between the frequency of companions to transiting planets with misaligned or eccentric orbits and those with well-aligned, circular orbits. We combine our expanded sample of radial velocity measurements with constraints from transit and secondary eclipse observations to provide improved measurements of the physical and orbital characteristics of all of the planets included in our survey.
- ID:
- ivo://CDS.VizieR/J/A+A/610/A20
- Title:
- HITEP. II. Transiting exoplanets imaging
- Short Name:
- J/A+A/610/A20
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the results of the second part of a high resolution imaging survey of hot Jupiter host stars. We search for binary companions to known transiting exoplanet host stars, in order to determine the multiplicity properties of hot Jupiter host stars. We also search for and characterise unassociated stars along the line of sight, allowing photometric and spectroscopic observations of the planetary system to be corrected for contaminating light.
- ID:
- ivo://CDS.VizieR/J/A+A/585/A53
- Title:
- Horizontal temperature at Venus upper atmosphere
- Short Name:
- J/A+A/585/A53
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- In this work, we analysed nadir observations of atmospheric infrared emissions carried out by VIRTIS, a high-resolution spectrometer on board the European spacecraft Venus Express. We focused on the ro-vibrational band of CO2 at 4.3 microns on the dayside, whose fluorescence originates in the Venus upper mesosphere and above. This is the first time that a systematic sounding of these non-local thermodynamic equilibrium (NLTE) emissions has been carried out in Venus using this geometry. As many as 143,218 spectra have been analysed on the dayside during the period 14/05/2006 to 14/09/2009. We designed an inversion method to obtain the atmospheric temperature from these non-thermal observations, including a NLTE line-by-line forward model and a pre-computed set of spectra for a set of thermal structures and illumination conditions. Our measurements sound a broad region of the upper mesosphere and lower thermosphere of Venus ranging from 10^-2^ to 10^-5^mb (which in the Venus International Reference Atmosphere, VIRA, is approximately 100-150km during the daytime) and show a maximum around 195+/-10K in the subsolar region, decreasing with latitude and local time towards the terminator. This is in qualitative agreement with predictions by a Venus Thermospheric General Circulation Model (VTGCM) after a proper averaging of altitudes for meaningful comparisons, although our temperatures are colder than the model by about 25K throughout. We estimate a thermal gradient of about 35K between the subsolar and antisolar points when comparing r data with nightside temperatures measured at similar altitudes by SPICAV, another instrument on Venus Express (VEx). Our data show a stable temperature structure through five years of measurements, but we also found episodes of strong heating/cooling to occur in the subsolar region of less than two days.
- ID:
- ivo://CDS.VizieR/J/ApJ/788/39
- Title:
- Hot Jupiter exoplanets host stars EW and abundances
- Short Name:
- J/ApJ/788/39
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The relative abundances of carbon and oxygen have long been recognized as fundamental diagnostics of stellar chemical evolution. Now, the growing number of exoplanet observations enable estimation of these elements in exoplanetary atmospheres. In hot Jupiters, the C/O ratio affects the partitioning of carbon in the major observable molecules, making these elements diagnostic of temperature structure and composition. Here we present measurements of carbon and oxygen abundances in 16 stars that host transiting hot Jupiter exoplanets, and we compare our C/O ratios to those measured in larger samples of host stars, as well as those estimated for the corresponding exoplanet atmospheres. With standard stellar abundance analysis we derive stellar parameters as well as [C/H] and [O/H] from multiple abundance indicators, including synthesis fitting of the [O I] {lambda}6300 line and non-LTE corrections for the O I triplet. Our results, in agreement with recent suggestions, indicate that previously measured exoplanet host star C/O ratios may have been overestimated. The mean transiting exoplanet host star C/O ratio from this sample is 0.54 (C/O_{sun}_=0.54), versus previously measured C/O_host star_ means of ~0.65-0.75. We also observe the increase in C/O with [Fe/H] expected for all stars based on Galactic chemical evolution; a linear fit to our results falls slightly below that of other exoplanet host star studies but has a similar slope. Though the C/O ratios of even the most-observed exoplanets are still uncertain, the more precise abundance analysis possible right now for their host stars can help constrain these planets' formation environments and current compositions.