- ID:
- ivo://CDS.VizieR/J/ApJ/733/123
- Title:
- The Wolf-Rayet content of M33 (NGC 598)
- Short Name:
- J/ApJ/733/123
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Wolf-Rayet (WR) stars are evolved massive stars, and the relative number of WC-type and WN-type WRs should vary with metallicity, providing a sensitive test of stellar evolutionary theory. The observed WC/WN ratio is much higher than that predicted by theory in some galaxies but this could be due to observational incompleteness for WN types, which have weaker lines. Previous studies of M33's WR content show a galactocentric gradient in the relative numbers of WCs and WNs, but only small regions have been surveyed with sufficient sensitivity to detect all of the WNs. Here, we present a sensitive survey for WRs covering all of M33, finding 55 new WRs, mostly of WN type. Our spectroscopy also improves the spectral types of many previously known WRs, establishing in one case that the star is actually a background quasar. The total number of spectroscopically confirmed WRs in M33 is 206, a number we argue is complete to ~5%, with most WRs residing in OB associations, although ~2% are truly isolated.
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Search Results
- ID:
- ivo://CDS.VizieR/III/223
- Title:
- 12th General Catalogue of MK Spectral Classification
- Short Name:
- III/223
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- This is the twelfth in a series of catalogs of MK spectral types and UBV photometry issued from Dearborn Observatory. It is based on an extensive search of literature published up to early 1995. Each catalog is essentially self-contained, with its separate selection of stars listed in order of increasing right ascension. Some classifications (indicated between parentheses) are inferred from photometric or astrometric considerations. The preferred identification is from the Henry Draper Catalog or the General Catalog of Variable Stars, with a Durchmusterung or other alternative as space permits.
- ID:
- ivo://CDS.VizieR/III/222
- Title:
- 14th General Catalogue of MK Spectral Classification
- Short Name:
- III/222
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- This is the fourteenth in a series of catalogs of MK spectral types and UBV photometry issued from Dearborn Observatory. It is based on an extensive search of the literature published from ~1997 to 1999. Each catalog is essentially self-contained, with its separate selection of stars listed in order of increasing right ascension. Some classifications (indicated between parentheses) are inferred from photometric or astrometric considerations. The preferred identification is from the Henry Draper Catalog or the General Catalog of Variable Stars, with a Durchmusterung or other alternative as space permits.
- ID:
- ivo://CDS.VizieR/III/206
- Title:
- 13th General Catalogue of MK Spectral Classification
- Short Name:
- III/206
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- A file of MK spectral types and UBV photometry maintained at Dearborn Observatory is presented here. It is based on an extensive literature search. The annex files (various clusters and associations, and SMC) are from the revised 12th catalogue.
- 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.
- ID:
- ivo://CDS.VizieR/J/AJ/153/258
- Title:
- 2007.5 to 2010.4 HST astrometry of HD 202206
- Short Name:
- J/AJ/153/258
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Using Hubble Space Telescope Fine Guidance Sensor astrometry and previously published radial velocity measures, we explore the exoplanetary system HD202206. Our modeling results in a parallax, {pi}_abs_=21.96+/-0.12 milliseconds of arc, a mass for HD202206B of M_B_=0.089_-0.006_^+0.007M_{Sun}_, and a mass for HD202206c of M_c_=17.9_-1.8_^+2.9^M_Jup_. HD202206 is a nearly face-on G + M binary orbited by a brown dwarf. The system architecture that we determine supports past assertions that stability requires a 5:1 mean motion resonance (we find a period ratio, P_c_/P_B_=4.92+/-0.04) and coplanarity (we find a mutual inclination, {Phi}=6{deg}+/-2{deg}).
- ID:
- ivo://CDS.VizieR/J/ApJ/749/79
- Title:
- Transition disks. II. Southern MoC
- Short Name:
- J/ApJ/749/79
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Transition disk objects are pre-main-sequence stars with little or no near-IR excess and significant far-IR excess, implying inner opacity holes in their disks. Here we present a multifrequency study of transition disk candidates located in Lupus I, III, IV, V, VI, Corona Australis, and Scorpius. Complementing the information provided by Spitzer with adaptive optics (AO) imaging (NaCo, VLT), submillimeter photometry (APEX), and echelle spectroscopy (Magellan, Du Pont Telescopes), we estimate the multiplicity, disk mass, and accretion rate for each object in our sample in order to identify the mechanism potentially responsible for its inner hole. We find that our transition disks show a rich diversity in their spectral energy distribution morphology, have disk masses ranging from <~1 to 10M_JUP_, and accretion rates ranging from <~10^-11^ to 10^-7.7^M_{sun}_/yr. Of the 17 bona fide transition disks in our sample, three, nine, three, and two objects are consistent with giant planet formation, grain growth, photoevaporation, and debris disks, respectively. Two disks could be circumbinary, which offers tidal truncation as an alternative origin of the inner hole.
- 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/152/24
- Title:
- Trigonometric parallaxes of 134 low-mass stars
- Short Name:
- J/AJ/152/24
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We report trigonometric parallaxes for 134 low-mass stars and brown dwarfs, of which 38 have no previously published measurement and 79 more have improved uncertainties. Our survey focused on nearby targets, so 119 are closer than 30pc. Of the 38 stars with new parallaxes, 14 are within 20pc and seven are likely brown dwarfs (spectral types later than L0). These parallaxes are useful for studies of kinematics, multiplicity, and spectrophotometric calibration. Two objects with new parallaxes are confirmed as young stars with membership in nearby young moving groups: LP 870-65 in AB Doradus and G161-71 in Argus. We also report the first parallax for the planet-hosting star GJ3470; this allows us to refine the density of its Neptune-mass planet. T-dwarf 2MASSJ12590470-4336243, previously thought to lie within 4pc, is found to be at 7.8pc, and the M-type star 2MASSJ01392170-3936088 joins the ranks of nearby stars as it is found to be within 10pc. Five stars that are overluminous and/or too red for their spectral types are identified and deserve further study as possible young 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.
