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6961. Triggered star formation in SFO 38
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.
6962. Triple systems (cool primary + hot binary)
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.
6963. 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.
6964. 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.
6965. 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.
6966. 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.
6967. T Tauri in and around bright-rimmed clouds
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.
6968. T Tauri stars UBrHalphaz photometry
ID:
ivo://CDS.VizieR/J/A+AS/120/267
Title:
T Tauri stars UBrHalphaz photometry
Short Name:
J/A+AS/120/267
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present the results of UBrH_{alpha}_z monitoring of a sample of T Tauri stars. The method of differential CCD photometry was applied. The observations span a range of ten days and show that eleven out of twelve sources varied during this time interval. These variations are correlated in all bands. Periods were detected (confidence level 99.99%) for eight out of eleven variable stars; one additional period was found at the 99.9% confidence level. Of those, one (BP Tau) agrees with previously published periods; two, GM Aur and IQ Tau, do not; six are new detections of periodicities. The sample is drawn from the Taurus-Auriga and Cepheus IV star-forming regions.
6969. [TT2009] 25 vicinity VI photometry
ID:
ivo://CDS.VizieR/J/A+A/629/L2
Title:
[TT2009] 25 vicinity VI photometry
Short Name:
J/A+A/629/L2
Date:
21 Oct 2021
Publisher:
CDS
Description:
Dwarf galaxies are key objects for small-scale cosmological tests like the abundance problems or the planes-of-satellites problem. A crucial task is therefore to get accurate information for as many nearby dwarf galaxies as possible. Using extremely deep, groundbased V and i-band Subaru Suprime Cam photometry with a completeness of i=27mag, we measure the distance of the dwarf galaxy [TT2009] 25 using the tip of the red giant branch (RGB) as a standard candle. This dwarf resides in the field around the Milky Way-analog NGC891. Using a Bayesian approach, we measure a distance of 10.28Mpc, which is consistent with the distance of NGC891, and thus confirm it as a member of NGC891. The dwarf galaxy follows the scaling relations defined by the Local Group dwarfs. We do not find an extended stellar halo around [TT2009] 25. In the small field of view of 100kpc covered by the survey, only one bright dwarf galaxy and the giant stream are apparent. This is comparable to the Milky Way, where one bright dwarf resides in the same volume, as well as the Sagittarius stream - excluding satellites which are farther away but would be projected in the line-of-sight. It is thus imperative to survey for additional dwarf galaxies in a larger area around NGC891 to test the abundance of dwarf galaxies and compare this to the number of satellites around the Milky Way.
6970. Tucana dSph CMD and star formation history
ID:
ivo://CDS.VizieR/J/A+A/630/A116
Title:
Tucana dSph CMD and star formation history
Short Name:
J/A+A/630/A116
Date:
21 Oct 2021
Publisher:
CDS
Description:
We report a new star formation history for the Tucana dwarf spheroidal galaxy, obtained from a new look at a deep HST/ACS colour-magnitude diagram. We combined information from the main sequence turn-off and the horizontal branch to resolve the ancient star formation rates on a finer temporal scale than previously possible. We show that Tucana experienced three major phases of star formation, two very close together at ancient times and the last one ending between 6 and 8 Gyr ago. We show that the three discrete clumps of stars on the horizontal branch are linked to the distinct episodes of star formation in Tucana. The spatial distribution of the clumps reveals that each generation of stars presents a higher concentration than the previous one. The simultaneous modelling of the horizontal branch and the main sequence turn-off also allows us to measure the amount of mass lost by red giant branch stars in Tucana with unprecedented precision, confirming dwarf spheroidals to be excellent laboratories to study the advanced evolution of low-mass stars.