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22471. Triton stellar occultation candidates
ID:
ivo://CDS.VizieR/J/AJ/119/936
Title:
Triton stellar occultation candidates
Short Name:
J/AJ/119/936
Date:
21 Oct 2021
Publisher:
CDS
Description:
As part of our ongoing program of predictions and observations of stellar occultations by solar system bodies, we have completed a search for candidates for occultations by Triton over the decade 2000 to 2009. Star positions near Triton's projected orbit as determined by the DE405 ephemeris and NEP016 orbit model were measured on (unfiltered) CCD strip scans recorded with the 0.6 m telescope at the George R. Wallace Astrophysical Observatory to a depth of 16th to 18th magnitude, depending on the quality of individual strip scans. Within 1.0" of the predicted orbit of Triton during this period, 128 stars were found, including 12 stars brighter than 14th magnitude. Only appulses with geocentric minimum separations of less than about 0.37" will result in an occultation visible from Earth, but potential errors in the ephemeris and in the positions of our candidates preclude accurate prediction of actual occultation events without further astrometry.
22472. Triton stellar occultation candidates
ID:
ivo://CDS.VizieR/J/AJ/109/1352
Title:
Triton stellar occultation candidates
Short Name:
J/AJ/109/1352
Date:
21 Oct 2021
Publisher:
CDS
Description:
We have completed a search for candidates for stellar occultations by Triton over the years 1995-1999 CCD strip scan images provided star positions in the relevant sky area to a depth of about 17.5Rmag. Over this time period, we find that Triton passes within 1.0arcsec of 75 stars. Appulses with geocentric minimum separations of less than 0.35arcsec will result in stellar occultations, but further astrometry and photometry is necessary to refine individual predictions for identification of actual occultations. Finder charts are included to aid in further studies and prediction refinement. The two most promising potential occultations, Tr176 and Tr180, occur in 1997.
22473. Triton stellar occultation candidates
ID:
ivo://CDS.VizieR/J/AJ/104/862
Title:
Triton stellar occultation candidates
Short Name:
J/AJ/104/862
Date:
21 Oct 2021
Publisher:
CDS
Description:
A search for Triton stellar occultation candidates for the period 1992-1994 has been completed with CCD strip-scanning observations. The search reached an R magnitude of about 17.4 and found 129 candidates within 1.5arcsec of Triton's ephemeris during this period. Of these events, we expect around 30 occultations to be visible from the Earth, indicating that a number of Triton occultation events should be visible from major observatories. Even the faintest of our candidate events could produce useful occultation data if observed with a large enough telescope. Our astrometric accuracy is inadequate to identify which of these appulse events will produce occultations on the Earth; further astrometry is needed to refine the predictions for positive occultation identification. To aid in selecting candidates for additional astrometric and photometric studies, we include finder charts and Earth-based visibility charts for each event.
22474. Trojan asteroids in the Kepler campaign 6 field
ID:
ivo://CDS.VizieR/J/AJ/153/116
Title:
Trojan asteroids in the Kepler campaign 6 field
Short Name:
J/AJ/153/116
Date:
21 Oct 2021
Publisher:
CDS
Description:
We report on a Kepler spacecraft survey during the K2 mission to characterize the rotational properties of 56 Trojan asteroids in the L4 cloud. More than one rotational period was observed for 51 of these targets, allowing for well constrained lightcurve rotation periods and amplitudes, five of which are found to be in conflict with previously published values. We find ~10% of objects have rotational periods longer than 100hr, an excess of slow rotators 10 times larger than suggested from the literature. Investigation of the rotational frequencies of our Kepler sample when combined with high-quality lightcurves in the literature reveals the distribution of rotational frequencies is non-Maxwellian even when consideration is given to size-dependent variations in rotational rate. From investigation of lightcurve shapes and amplitudes, we estimate the binary fraction within the Trojan population to be ~6%-36% depending on the methodology utilized to identify binary candidates.
22475. TROY project. I.
ID:
ivo://CDS.VizieR/J/A+A/609/A96
Title:
TROY project. I.
Short Name:
J/A+A/609/A96
Date:
21 Oct 2021
Publisher:
CDS
Description:
The detection of Earth-like planets, exocomets or Kuiper belts show that the different components found in the solar system should also be present in other planetary systems. Trojans are one of these components and can be considered fossils of the first stages in the life of planetary systems. Their detection in extrasolar systems would open a new scientific window to investigate formation and migration processes. In this context, the main goal of the TROY project is to detect exotrojans for the first time and to measure their occurrence rate (eta-Trojan). In this first paper, we describe the goals and methodology of the project. Additionally, we used archival radial velocity data of 46 planetary systems to place upper limits on the mass of possible trojans and investigate the presence of co-orbital planets down to several tens of Earth masses. We used archival radial velocity data of 46 close-in (P<5-days) transiting planets (without detected companions) with information from high-precision radial velocity instruments. We took advantage of the time of mid-transit and secondary eclipses (when available) to constrain the possible presence of additional objects co-orbiting the star along with the planet. This, together with a good phase coverage, breaks the degeneracy between a trojan planet signature and signals coming from additional planets or underestimated eccentricity. We identify nine systems for which the archival data provide >1-sigma evidence for a mass imbalance between L4 and L5. Two of these systems provide >2{sigma} detection, but no significant detection is found among our sample. We also report upper limits to the masses at L4/L5 in all studied systems and discuss the results in the context of previous findings.
22476. Trumpler 14 and 16 in the Carina nebula
ID:
ivo://CDS.VizieR/J/A+A/603/A81
Title:
Trumpler 14 and 16 in the Carina nebula
Short Name:
J/A+A/603/A81
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present the first extensive spectroscopic study of the global population in star clusters Trumpler 16, Trumpler 14, and Collinder 232 in the Carina nebula, using data from the Gaia-ESO Survey, down to solar-mass stars. In addition to the standard homogeneous survey data reduction, a special processing was applied here because of the bright nebulosity surrounding Carina stars. We find about 400 good candidate members ranging from OB types down to slightly subsolar masses. About 100 heavily reddened early-type Carina members found here were previously unrecognized or poorly classified, including two candidate O stars and several candidate Herbig Ae/Be stars. Their large brightness makes them useful tracers of the obscured Carina population. The spectroscopically derived temperatures for nearly 300 low-mass members enables the inference of individual extinction values and the study of the relative placement of stars along the line of sight. We find a complex spatial structure with definite clustering of low-mass members around the most massive stars and spatially variable extinction. By combining the new data with existing X-ray data, we obtain a more complete picture of the three-dimensional spatial structure of the Carina clusters and of their connection to bright and dark nebulosity and UV sources. The identification of tens of background giants also enables us to determine the total optical depth of the Carina nebula along many sightlines. We are also able to put constraints on the star formation history of the region with Trumpler 14 stars found to be systematically younger than stars in other subclusters. We find a large percentage of fast-rotating stars among Carina solar-mass members, which provide new constraints on the rotational evolution of pre-main-sequence stars in this mass range.
22477. 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.
22478. Trumpler 14 JHKL' photometry
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.
22479. Trumpler 5 photometric BV catalog
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.
22480. Tr16-22. V and V/I Stokes parameters
ID:
ivo://CDS.VizieR/J/A+A/596/A44
Title:
Tr16-22. V and V/I Stokes parameters
Short Name:
J/A+A/596/A44
Date:
21 Oct 2021
Publisher:
CDS
Description:
The detection of bright, hard, and variable X-ray emission in Tr16-22 prompted spectropolarimetric observations of this star, which in turn led to the discovery of a surface magnetic field. We want to further constrain the properties of this star, in particular to verify whether X-ray variations are correlated to changes in optical emission lines and magnetic field strength, as expected from the oblique rotator model that is widely accepted for magnetic O stars. We have obtained new low-resolution spectropolarimetric and long-term high-resolution spectroscopic monitoring of Tr16-22, and we also analyse new, serendipitous X-ray data.

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