- ID:
- ivo://CDS.VizieR/J/AJ/157/87
- Title:
- Times of minima for 21 early-type SMC eccentric EBs
- Short Name:
- J/AJ/157/87
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the apsidal motion and light-curve analyses of 21 eccentric eclipsing binaries located in the Small Magellanic Cloud. Most of these systems have never been studied before, hence their orbital and physical properties as well as the apsidal motion parameters are given here for the first time. All the systems are of early spectral type, having orbital periods up to 4 days. The apsidal motion periods were derived to be from 7.2 to 200 yr (OGLE-SMC-ECL-2194 having the shortest apsidal period among known main-sequence systems). The orbital eccentricities are usually rather mild (median of about 0.06), the maximum eccentricity being 0.33. For the period analysis using O-C diagrams of eclipse timings, in total 951 minima were derived from survey photometry as well as our new data. Moreover, six systems show some additional variation in their O-C diagrams, which should indicate the presence of hidden additional components in them. According to our analysis these third-body variations have periods from 6.9 to 22 yr.
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- 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/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.
- 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.
- ID:
- ivo://CDS.VizieR/J/ApJS/82/117
- Title:
- UBV and H-beta in Sco-Cen association
- Short Name:
- J/ApJS/82/117
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- As part of a thorough study of the luminosity function of Sco-Cen, UBV, and H_{beta}_ photometry has been acquired for a large number of mid B- to late A-type stars which are within or surrounding the Scorpius-Centaurus OB association. UBV and H_{beta}_ photoelectric measures have been obtained for all the B stars without previous observations and for many of those with in the large field 280deg<=l<=362deg, +10deg<=b<=+40deg, and m-M<=7.5mag. Within the upper Scopius subgroup (ScoOB2), 341deg<=l<=362deg, +10=<b=<30deg, UBV and H_{beta}_ photometry was obtained for all B stars listed in the MSC(HD) catalog. As well, UBV measures were obtained for all the A-type stars within this field.
- ID:
- ivo://CDS.VizieR/J/A+A/555/A50
- Title:
- UBVIc photometry of stars in Westerlund 2
- Short Name:
- J/A+A/555/A50
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- A new X-ray, UBVIc, and JHKs study of the young cluster Westerlund 2 was undertaken to resolve discrepancies tied to the cluster's distance. Existing spectroscopic observations for bright cluster members and new multi-band photometry imply a reddening relation toward Westerlund 2 described by E(U-B)/E(B-V)=0.63+0.02E(B-V). Variable-extinction analyses for Westerlund 2 and nearby IC 2581 based upon spectroscopic distance moduli and ZAMS fitting yield values of R_V_=A_V_/E(B-V)=3.88+/-0.18 and 3.77+/-0.19, respectively, and confirm prior assertions that anomalous interstellar extinction is widespread throughout Carina. The results were confirmed by applying the color-difference method to UBVRIcJHKs data for 19 spectroscopically observed cluster members, yielding R_V_=3.85+/-0.07. The derived distance to Westerlund 2 of d=2.85+/-0.43kpc places the cluster on the far side of the Carina spiral arm. The cluster's age is no more than {tau}~2x10^6^yr as inferred from the cluster's brightest stars and an X-ray (Chandra) cleaned analysis of its pre-main-sequence demographic. Four Wolf-Rayet stars in the cluster core and surrounding corona (WR20a, WR20b, WR20c, and WR20aa) are very likely cluster members, and their inferred luminosities are consistent with those of other late-WN stars in open clusters. The color-magnitude diagram for Westerlund 2 also displays a gap at spectral type B0.5~V with associated color spread at higher and lower absolute magnitudes that might be linked to close binary mergers. These features, in conjunction with the evidence for mass loss from the WR stars, may help to explain the high flux of {gamma}-rays, cosmic rays, and X-rays from the direction toward Westerlund 2.
- ID:
- ivo://CDS.VizieR/J/A+A/457/637
- Title:
- UBVJHK synthetic photometry of Galactic O stars
- Short Name:
- J/A+A/457/637
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The development of powerful infrared observational techniques enables the study of very extincted objects and young embedded star-forming regions. This is especially interesting in the context of massive stars that form and spend a non negligible fraction of their life still enshrouded in their parental molecular cloud. Spectrophotometric calibrations are thus necessary to constrain the physical properties of heavily extincted objects.
- ID:
- ivo://CDS.VizieR/J/AN/331/274
- Title:
- UBV photometry of early-type stars
- Short Name:
- J/AN/331/274
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- UBV measurements of early-type stars, mostly eclipsing binaries, obtained at La Silla in the years 1990 to 1994 with the ESO 50cm telescope are presented. Most of these data were already used in our individual studies of several binaries. Now all photometric measurements were reduced again with an advanced technique and are made available electronically. Our data for MY Ser have not yet been published; new light curve is given and solved. The result is that MY Ser is a contact binary, with very large fill-out parameter. Also a light curve and its solution for V1051 Cen are provided, and the problem of the period of V871 Cen is pointed out. Besides binaries (and the comparison and check stars) data for several stars in southern H II regions are included. Extinction and transformation coefficients are given.
- ID:
- ivo://CDS.VizieR/II/232
- Title:
- UBV photometry of selected regions in the MCs
- Short Name:
- II/232
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- This catalogue groups broad-band CCD photometry made in 8 regions of the Magellanic Clouds which were used for the study of stellar populations in the Magellanic Clouds. The photometry yielded 293693 BV entries with 136155 having additional U information, published or to be published in 4 different papers.
- ID:
- ivo://CDS.VizieR/J/ApJS/168/128
- Title:
- UBVRcIc photometry of FHB and metal-poor stars
- Short Name:
- J/ApJS/168/128
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We report broadband UBV and/or BVR_C_I_C_ CCD photometry for a total of 1857 stars in the thick-disk and halo populations of the Galaxy. The majority of our targets were selected as candidate field horizontal-branch or other A-type stars (FHB/A, N=576), or candidate low-metallicity stars (N=1221), from the HK and Hamburg/ESO objective-prism surveys. Similar data for a small number of additional stars from other samples are also reported.
