- ID:
- ivo://CDS.VizieR/J/A+A/640/A112
- Title:
- TRAPPIST-1 transit timings
- Short Name:
- J/A+A/640/A112
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- With more than 1000 hours of observation from Feb 2016 to Oct 2019, the Spitzer Exploration Program Red Worlds (ID: 13067, 13175 and 14223) exclusively targeted TRAPPIST-1, a nearby (12pc) ultracool dwarf star, finding that it is orbited by seven transiting Earth-sized planets. At least three of these planets orbit within the classical habitable zone of the star, and all of them are well-suited for a detailed atmospheric characterization with the upcoming JWST. The main goals of the Spitzer Red Worlds program were (1) to explore the system for new transiting planets, (2) to intensively monitor the planets' transits to yield the strongest possible constraints on their masses, sizes, compositions, and dynamics, and (3) to assess the infrared variability of the host star. In this paper, we present the global results of the project. We analyzed 88 new transits and combined them with 100 previously analyzed transits, for a total of 188 transits observed at 3.6 or 4.5um. For a comprehensive study, we analyzed all light curves both individually and globally. We also analyzed 29 occultations (secondary eclipses) of planet b and eight occultations of planet c observed at 4.5um to constrain the brightness temperatures of their daysides. We identify several orphan transit-like structures in our Spitzer photometry, but all of them are of low significance. We do not confirm any new transiting planets. We do not detect any significant variation of the transit depths of the planets throughout the different campaigns. Comparing our individual and global analyses of the transits, we estimate for TRAPPIST-1 transit depth measurements mean noise floors of ~35 and 25ppm in channels 1 and 2 of Spitzer/IRAC, respectively. We estimate that most of this noise floor is of instrumental origins and due to the large inter-pixel inhomogeneity of IRAC InSb arrays, and that the much better interpixel homogeneity of JWST instruments should result in noise floors as low as 10ppm, which is low enough to enable the atmospheric characterization of the planets by transit transmission spectroscopy. Our analysis reveals a few outlier transits, but we cannot conclude whether or not they correspond to spot or faculae crossing events. We construct updated broadband transmission spectra for all seven planets which show consistent transit depths between the two Spitzer channels. Although we are limited by instrumental precision, the combined transmission spectrum of planet b to g tells us that their atmospheres seem unlikely to be CH_4_-dominated. We identify and model five distinct high energy flares in the whole dataset, and discuss our results in the context of habitability. Finally, we fail to detect occultation signals of planets b and c at 4.5um, and can only set 3{sigma} upper limits on their dayside brightness temperatures (611K for b 586K for c).
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Search Results
- ID:
- ivo://CDS.VizieR/J/ApJ/893/27
- Title:
- TRENDS high-contrast imaging survey. VIII.
- Short Name:
- J/ApJ/893/27
- Date:
- 19 Jan 2022 00:39:50
- Publisher:
- CDS
- Description:
- The physical properties of faint stellar and substellar objects often rely on indirect, model-dependent estimates. For example, the masses of brown dwarfs are usually inferred using evolutionary models, which are age dependent and have yet to be properly calibrated. With the goal of identifying new benchmark objects to test low-mass stellar and substellar models, we have carried out a comprehensive adaptive optics survey as part of the TaRgetting bENchmark-objects with the Doppler Spectroscopy (TRENDS) high-contrast imaging program. Using legacy radial velocity measurements from the High Resolution Echelle Spectrometer at Keck, we have identified several dozen stars that show long-term Doppler accelerations. We present follow-up high-contrast observations from the campaign and report the discovery of 31 comoving companions, as well as 11 strong candidate companions, to solar-type stars with well-determined parallax and metallicity values. Benchmark objects of this nature lend themselves to orbit determinations, dynamical mass estimates, and independent compositional assessment. This compendium of benchmark objects will serve as a convenient test group to substantiate theoretical evolutionary and atmospheric models near the hydrogen fusing limit.
- ID:
- ivo://CDS.VizieR/J/A+A/510/A107
- Title:
- TrES-2b multi-band transit observations
- Short Name:
- J/A+A/510/A107
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a new data set of transit observations of the TrES-2b exoplanet taken in spring 2009, using the 1.2m Oskar-Luehning telescope (OLT) of Hamburg Observatory and the 2.2m telescope at Calar Alto Observatory using BUSCA (Bonn University Simultaneous CAmera). Both the new OLT data, taken with the same instrumental setup as our data taken in 2008, as well as the simultaneously recorded multicolor BUSCA data confirm the low inclination values reported previously, and in fact suggest that the TrES-2b exoplanet has already passed the first inclination threshold (i_min,1_=83.417{deg}) and is not eclipsing the full stellar surface any longer.
1304. TrES-4b RV and Ic curves
- ID:
- ivo://CDS.VizieR/J/A+A/575/L15
- Title:
- TrES-4b RV and Ic curves
- Short Name:
- J/A+A/575/L15
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We update the TrES-4 system parameters using high-precision HARPS-N radial-velocity measurements and new photometric light curves. A combined spectroscopic and photometric analysis allows us to determine a spectroscopic orbit with a semi-amplitude K=51+/-3m/s. The derived mass of TrES-4b is found to be M_p_=0.49+/-0.04M_Jup_, significantly lower than previously reported. Combined with the large radius (R_p_=1.84_-0.09_^+0.08^R_Jup_) inferred from our analysis, TrES-4b becomes the transiting hot Jupiter with the second-lowest density known. We discuss several scenarios to explain the puzzling discrepancy in the mass of TrES-4b in the context of the exotic class of highly inflated transiting giant planets.
- ID:
- ivo://CDS.VizieR/J/A+A/608/A26
- Title:
- TrES-3b UBVIz' light curves
- Short Name:
- J/A+A/608/A26
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Transit events of extrasolar planets offer the opportunity to study the composition of their atmospheres. Previous work on transmission spectroscopy of the close-in gas giant TrES-3 b revealed an increase in absorption towards blue wavelengths of very large amplitude in terms of atmospheric pressure scale heights, too large to be explained by Rayleigh- scattering in the planetary atmosphere. We present a follow-up study of the optical transmission spectrum of the hot Jupiter TrES-3 b to investigate the strong increase in opacity towards short wavelengths found by a previous study. Furthermore, we aim to estimate the effect of stellar spots on the transmission spectrum. This work uses previously published long slit spectroscopy transit data of the Gran Telescopio Canarias (GTC) and published broad band observations as well as new observations in different bands from the near-UV to the near-IR, for a homogeneous transit light curve analysis. Additionally, a long-term photometric monitoring of the TrES-3 host star was performed. Our newly analysed GTC spectroscopic transit observations show a slope of much lower amplitude than previous studies. We conclude from our results the previously reported increasing signal towards short wavelengths is not intrinsic to the TrES-3 system. Furthermore, the broad band spectrum favours a flat spectrum. Long-term photometric monitoring rules out a significant modification of the transmission spectrum by unocculted star spots.
- ID:
- ivo://CDS.VizieR/J/A+A/656/A88
- Title:
- TrES-5 photometric timeseries
- Short Name:
- J/A+A/656/A88
- Date:
- 22 Feb 2022
- Publisher:
- CDS
- Description:
- The orbital motion of the transiting hot Jupiter TrES-5 b was reported to be perturbed by a planetary companion on a nearby orbit. Such compact systems do not frequently occur in nature, and learning their orbital architecture could shed some light on hot Jupiters' formation processes. We acquired fifteen new precise photometric time series for twelve transits of TrES-5 b between June 2019 and October 2020 using 0.9-2.0m telescopes. The method of precise transit timing was employed to verify the deviation of the planet from the Keplerian motion. Although our results show no detectable short-time variation in the orbital period of TrES-5 b and the existence of the additional nearby planet is not confirmed, the new transits were observed about two minutes earlier than expected. We conclude that the orbital period of the planet could vary in a long timescale. We found that the most likely explanation of the observations is the line-of-sight acceleration of the system's barycentre due to the orbital motion induced by a massive, wide-orbiting companion.
- ID:
- ivo://CDS.VizieR/J/MNRAS/389/925
- Title:
- Triple and quadruple stars
- Short Name:
- J/MNRAS/389/925
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The statistics of catalogued quadruple stars consisting of two binaries (hierarchy 2+2), is studied in comparison with triple stars, with respective sample sizes of 81 and 725. Seven representative quadruple systems are discussed in greater detail.
- ID:
- ivo://CDS.VizieR/J/A+A/616/A75
- Title:
- Triple system HD150136 radial velocities
- Short Name:
- J/A+A/616/A75
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The triple system HD 150136 is composed of an O3 V((f^*^))-O3.5 V((f^+^)) primary, of an O5.5-6 V((f)) secondary and of a more distant O6.5-7 V((f)) tertiary. The latter component went through periastron in 2015-2016, an event that will not occur again within the next eight years. We aim to analyse the tertiary periastron passage to determine the orbital properties of the outer system, to constrain its inclination and its eccentricity, and to determine the actual masses of the three components of the system. We conducted an intensive spectroscopic monitoring of the periastron passage of the tertiary component and combined them with new interferometric measurements. This allows us to derive the orbital solution of the outer orbit in three-dimensional space. We also obtained the light curve of the system to further constrain the inclination of the inner binary. We determine an orbital period of 8.61+/-0.02 years, an eccentricity of 0.682+/-0.002, and an inclination of 106.18+/-0.14{deg} for the outer orbit. The actual masses of the inner system and of the tertiary object are 72.32_-8.49_^+8.45^M_{sun}_ and 15.54_-4.97_^+4.96^M_{sun}_, respectively. From the mass of the inner system and accounting for the known mass ratio between the primary and the secondary, we determine actual masses of 42.81M_{sun}_ and 29.51M_{sun}_ for the primary and the secondary components, respectively. We infer, from the different mass ratios and the inclination of the outer orbit, an inclination of 62.4{deg} for the inner system. This value is confirmed by photometry. Grazing eclipses and ellipsoidal variations are detected in the light curve of HD 150136. We also compute the distance of the system to 1.096+/-0.274kpc. By combining spectroscopy, interferometry, and photometry, HD 150136 offers us a unique chance to compare theory and observations. The masses estimated through our analysis are smaller than those constrained by evolutionary models. The formation of this triple system suggests similar ages for the three components within the errorbars. Finally, we show that Lidov-Kozai cycles have no effect on the evolution of the inner binary, which suggests that the latter will experience mass transfer leading to a merger of the two stars.
- ID:
- ivo://CDS.VizieR/J/ApJ/885/9
- Title:
- Triple system HD 28363; RVel and visual observations
- Short Name:
- J/ApJ/885/9
- Date:
- 15 Mar 2022 07:55:42
- Publisher:
- CDS
- Description:
- The star HD28363 in the Hyades cluster has been known for over a century as a visual binary with a period of 40yr. The secondary is, in turn, a single-lined spectroscopic binary with a 21day period. Here we report extensive spectroscopic monitoring of this hierarchical triple system that reveals the spectral lines of the third star for the first time. Combined with astrometric information, this makes it possible to determine the dynamical masses of all three stars. Only six other binaries in the Hyades have had their individual component masses determined dynamically. We infer the properties of the system by combining our radial-velocity measurements with visual observations, lunar occultation measurements, and with proper motions from the Hipparcos and Gaia missions that provide a constraint on the astrometric acceleration. We derive a mass of 1.341_-0.024_^+0.026^M{odot} for the visual primary, and 1.210{+/-}0.021 and 0.781{+/-}0.014 M{sun} for the other two stars. These measurements along with those for the other six systems establish an empirical mass-luminosity relation in the Hyades that is in broad agreement with current models of stellar evolution for the known age and chemical composition of the cluster.
- ID:
- ivo://CDS.VizieR/J/AJ/127/2915
- Title:
- Triple systems (cool primary + hot binary)
- Short Name:
- J/AJ/127/2915
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- In the course of comparing parameters of evolved cool star plus hot main-sequence star binaries with theoretical isochrones, some discrepancies are found between implied stellar masses and the spectroscopic binary mass function or the measured angular separation. These are naturally explained if there is a third star in the system. Multiplicity is also required to explain some comparisons of "cool plus hot binary" IUE and optical spectral energy distribution analysis with measured flux ratios, especially Tycho's two-color photometry of separate components. Out of a sample of 136 cool-plus-hot binary star systems under study, measurements are now indicating several systems considered double (HD 5373, 23089, 26673, 29094, 49126, 71129, 149379, 179002, 187299), and probably a few others (including HD 136415), to have at least three stellar components. Several other cases of suspected triple systems are confirmed. For comparison, there are eight known triples included in the project. In all, about 25% of the systems contain three or more components within a few arcseconds. Estimated separations are provided, which may be of use when not known from interferometry. In general, the triple systems have one post-main-sequence component and two upper main-sequence components, usually revolving around each other. One new triple system, HD 149379, has as its middle component an F giant in the brief first crossing of the Hertzsprung gap.
