- ID:
- ivo://CDS.VizieR/J/ApJS/210/25
- Title:
- Transit timing variation for 15 planetary pairs. II.
- Short Name:
- J/ApJS/210/25
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Following on from Paper I (Cat. J/ApJS/208/22) in this series, I report the confirmation of a further 30 planets in 15 multiple-planet systems via transit timing variations (TTVs), using the publicly available Kepler light curves (Q0-Q16). All 15 pairs are near first-order mean motion resonances, showing sinusoidal TTVs consistent with theoretically predicted periods, which demonstrate they are orbiting and interacting in the same systems. Although individual masses cannot be accurately extracted based only on TTVs (because of the well known degeneracy between mass and eccentricity), the measured TTV phases and amplitudes can still place relatively tight constraints on their mass ratios and upper limits on their masses, which confirm their planetary nature. Some of these systems (KOI-274, KOI-285, KOI-370, and KOI-2672) are relatively bright and thus suitable for further follow-up observations.
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Search Results
- ID:
- ivo://CDS.VizieR/J/AJ/159/239
- Title:
- Transmission Spectroscopy Metric of exoplanets
- Short Name:
- J/AJ/159/239
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Recent years have seen increasing interest in the characterization of sub-Neptune-sized planets because of their prevalence in the Galaxy, contrasted with their absence in our solar system. HD97658 is one of the brightest stars hosting a planet of this kind, and we present the transmission spectrum of this planet by combining four Hubble Space Telescope transits, 12 Spitzer/IRAC transits, and eight Microvariability and Oscillations of Stars Telescope (MOST) transits of this system. Our transmission spectrum has a higher signal-to-noise ratio than those from previous works, and the result suggests that the slight increase in transit depth from wavelength 1.1-1.7{mu}m reported in previous works on the transmission spectrum of this planet is likely systematic. Nonetheless, our atmospheric modeling results are inconclusive, as no model provides an excellent match to our data. Nonetheless, we find that atmospheres with high C/O ratios (C/O~>0.8) and metallicities of ~>100 solar metallicity are favored. We combine the mid-transit times from all of the new Spitzer and MOST observations and obtain an updated orbital period of P=9.489295{+/-}0.000005, with a best-fit transit time center at T0=2456361.80690{+/-}0.00038(BJD). No transit timing variations are found in this system. We also present new measurements of the stellar rotation period (34{+/-}2days) and stellar activity cycle (9.6yr) of the host star HD97658. Finally, we calculate and rank the Transmission Spectroscopy Metric of all confirmed planets cooler than 1000K and with sizes between 1R_{Earth}_ and 4R_{Earth}_. We find that at least a third of small planets cooler than 1000K can be well characterized using James Webb Space Telescope, and of those, HD97658b is ranked fifth, meaning that it remains a high-priority target for atmospheric characterization.
- ID:
- ivo://CDS.VizieR/J/MNRAS/497/3790
- Title:
- TRAPPIST-South UCD Transit Survey
- Short Name:
- J/MNRAS/497/3790
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We conducted a global analysis of the TRAPPIST Ultra-Cool Dwarf Transit Survey - a prototype of the SPECULOOS transit search conducted with the TRAPPIST-South robotic telescope in Chile from 2011 to 2017 - to estimate the occurrence rate of close-in planets such as TRAPPIST-1b orbiting ultra-cool dwarfs. For this purpose, the photometric data of 40 nearby ultra-cool dwarfs were reanalysed in a self-consistent and fully automated manner starting from the raw images. The pipeline developed specifically for this task generates differential light curves, removes non-planetary photometric features and stellar variability, and searches for transits. It identifies the transits of TRAPPIST-1b and TRAPPIST-1c without any human intervention. To test the pipeline and the potential output of similar surveys, we injected planetary transits into the light curves on a star-by-star basis and tested whether the pipeline is able to detect them. The achieved photometric precision enables us to identify Earth-sized planets orbiting ultra-cool dwarfs as validated by the injection tests. Our planet-injection simulation further suggests a lower limit of 10 per cent on the occurrence rate of planets similar to TRAPPIST-1b with a radius between 1 and 1.3 R_{Earth}_ and the orbital period between 1.4 and 1.8d.
- ID:
- ivo://CDS.VizieR/J/ApJ/793/62
- Title:
- Triangulum-Andromeda stellar properties
- Short Name:
- J/ApJ/793/62
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- As large-scale stellar surveys have become available over the past decade, the ability to detect and characterize substructures in the Galaxy has increased dramatically. These surveys have revealed the Triangulum-Andromeda (TriAnd) region to be rich with substructures in the distance range 20-30 kpc, and the relation of these features to each other, if any, remains unclear. An exploration using Two Micron All Sky Survey (2MASS) photometry reveals not only the faint sequence in M giants detected by Rocha-Pinto et al. (2004ApJ...615..732R) spanning the range 100{deg}<l<160{deg} and -50{deg}<b<-15{deg}, but, in addition, a second, brighter and more densely populated sequence. These sequences are likely associated with the distinct main sequences (MSs) discovered (and labeled TriAnd1 and TriAnd2) by Martin et al. (2007ApJ...668L.123M) in an optical survey in the direction of M31, where TriAnd2 is the optical counterpart of the fainter red giant branch (RGB)/asymptotic giant branch sequence of Rocha-Pinto et al. Here, the age, distance, and metallicity ranges for TriAnd1 and TriAnd2 are estimated by simultaneously fitting isochrones to the 2MASS RGB tracks and the optical MS/MS turn-off features. The two populations are clearly distinct in age and distance: the brighter sequence (TriAnd1) is younger (6-10 Gyr) and closer (distance of ~15-21 kpc), whereas the fainter sequence (TriAnd2) is older (10-12 Gyr) and at an estimated distance of ~24-32 kpc. A comparison with simulations demonstrates that the differences and similarities between TriAnd1 and TriAnd2 can simultaneously be explained if they represent debris originating from the disruption of the same dwarf galaxy, but torn off during two distinct pericentric passages.
- ID:
- ivo://CDS.VizieR/J/ApJ/717/1067
- Title:
- Triggered star formation in SFO 38
- Short Name:
- J/ApJ/717/1067
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We have investigated the young stellar population in and around SFO 38, one of the massive globules located in the northern part of the Galactic HII region IC 1396, using the Spitzer IRAC and MIPS observations (3.6-24um), and followed up with ground-based optical photometric and spectroscopic observations. Based on the IRAC and MIPS colors and H{alpha} emission, we identify ~45 young stellar objects (Classes 0/I/II) and 13 probable pre-main-sequence candidates. We derive the spectral types (mostly K- and M-type stars), effective temperatures, and individual extinction of the relatively bright and optically visible Class II objects. Using the width of the H{alpha} emission line measured at 10% peak intensity, we derive the mass accretion rates of individual objects to be between 10^-10^ and 10^-8^M_{sun}_/yr.
- 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.
5217. Trumpler 16 in the CCCP
- ID:
- ivo://CDS.VizieR/J/ApJS/194/12
- Title:
- Trumpler 16 in the CCCP
- Short Name:
- J/ApJS/194/12
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Trumpler 16 is a well-known rich star cluster containing the eruptive supergiant {eta} Carinae and located in the Carina star-forming complex. In the context of the Chandra Carina Complex Project, we study Trumpler 16 using new and archival X-ray data. A revised X-ray source list of the Trumpler 16 region contains 1232 X-ray sources including 1187 likely Carina members. These are matched to 1047 near-infrared counterparts detected by the HAWK-I instrument at the Very Large Telescope allowing for better selection of cluster members. The cluster is irregular in shape. Although it is roughly circular, there is a high degree of sub-clustering, with no noticeable central concentration and an extension to the southeast. We estimate the total Trumpler 16 pre-main-sequence population to be >6500 Class II and Class III X-ray sources. An overall K-excess disk frequency of ~8.9% is derived using the X-ray-selected sample, although there is some variation among the sub-clusters, especially in the southeastern extension. X-ray emission is detected from 29 high-mass stars with spectral types between B2 and O3.
- ID:
- ivo://CDS.VizieR/J/A+A/476/199
- Title:
- Trumpler 14 JHKL' photometry
- Short Name:
- J/A+A/476/199
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the deepest and highest resolution near-infrared imaging to date of cluster Trumpler 14 in Carina. Our goal is to identify and characterise the young stellar population of this massive cluster. We made use of deep and wide-field NIR images from NTT and VLT observations, that were sensitive enough to detect substellar sources at the distance to this cluster, and at high enough resolution (VLT diffraction limited) to fully resolve the core of the cluster crowded with O stars.
- ID:
- ivo://CDS.VizieR/J/MNRAS/446/1411
- Title:
- Trumpler 5 photometric BV catalog
- Short Name:
- J/MNRAS/446/1411
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- As part of a long-term programme, we analyse the evolutionary status and properties of the old and populous open cluster Trumpler 5 (Tr 5), located in the Galactic anticentre direction, almost on the Galactic plane. Tr 5 was observed with Wide Field Imager@MPG/ESO Telescope using the Bessel U, B, and V filters. The cluster parameters have been obtained using the synthetic colour-magnitude diagram (CMD) method, i.e. the direct comparison of the observational CMD with a library of synthetic CMDs generated with different stellar evolution sets (Padova, FRANEC, and FST). Age, reddening, and distance are derived through the synthetic CMD method using stellar evolutionary models with subsolar metallicity (Z=0.004 or Z=0.006). Additional spectroscopic observations with Ultraviolet VLT Echelle Spectrograph@Very Large Telescope of three red clump stars of the cluster were used to determine more robustly the chemical properties of the cluster. Our analysis shows that Tr 5 has subsolar metallicity, with [Fe/H]=-0.403+/-0.006 dex (derived from spectroscopy), age between 2.9 and 4 Gyr (the lower age is found using stellar models without core overshooting), reddening E(B-V) in the range 0.60-0.66 mag complicated by a differential pattern (of the order of ~+/-0.1mag), and distance modulus (m-M)_0_=12.4+/-0.1mag.
- ID:
- ivo://CDS.VizieR/J/MNRAS/396/964
- Title:
- T Tauri in and around bright-rimmed clouds
- Short Name:
- J/MNRAS/396/964
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The aim of this paper is to quantitatively testify the 'small-scale sequential star formation' hypothesis in and around bright-rimmed clouds (BRCs). As a continuation of the recent attempt by Ogura et al. (2007PASJ...59..199O), we have carried out BVIc photometry of four more BRC aggregates along with deeper re-observations of two previously observed BRCs. Again, quantitative age gradients are found in almost all the BRCs studied in the present work. Archival Spitzer/Infrared Array Camera data also support this result.
