- ID:
- ivo://CDS.VizieR/J/A+A/580/A129
- Title:
- Sulphur in the Sculptor dSph
- Short Name:
- J/A+A/580/A129
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- In Galactic halo stars, sulphur has been shown to behave like other {alpha}-elements, but until now, no comprehensive studies have been done on this element in stars of other galaxies. Here, we use high-resolution ESO VLT/FLAMES/GIRAFFE spectra to determine sulphur abundances for 85 stars in the Sculptor dwarf spheroidal galaxy, covering the metallicity range -2.5<=[Fe/H]<=-0.8. The abundances are derived from the SI triplet at 9213, 9228, and 9238{AA}. These lines have been shown to be sensitive to departure from local thermodynamic equilibrium, i.e. NLTE effects. Therefore, we present new NLTE corrections for a grid of stellar parameters covering those of the target stars. The NLTE-corrected sulphur abundances in Sculptor show the same behaviour as other {alpha}-elements in that galaxy (such as Mg, Si, and Ca). At lower metallicities ([Fe/H]<~-2) the abundances are consistent with a plateau at [S/Fe]=~+0.16, similar to what is observed in the Galactic halo, [S/Fe]=~+0.2. With increasing [Fe/H], the [S/Fe] ratio declines, reaching negative values at [Fe/H]>-1.5. The sample also shows an increase in [S/Mg] with [Fe/H], most probably because of enrichment from Type Ia supernovae.
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1342. Super-metal-rich stars
- ID:
- ivo://CDS.VizieR/J/PASP/113/1365
- Title:
- Super-metal-rich stars
- Short Name:
- J/PASP/113/1365
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present Lick spectral indices for a complete sample of 139 candidate super-metal-rich stars of different luminosity classes (MK type from I to V). For 91 of these stars we were able to identify, in an accompanying paper, the fundamental atmosphere parameters. This confirms that at least 2/3 of the sample consists of stars with [Fe/H] in excess of +0.1 dex. Optical indices for both observations and fiducial synthetic spectra have been calibrated to the Lick system according to Worthey et al. (1994, Cat. <J/ApJS/94/687>) and include the FeI indices of Fe5015, Fe5270, and Fe5335 and the MgI and MgH indices of Mg_2_ and Mg_b_ at 5180{AA}. The internal accuracy of the observations is found to be {sigma}(Fe5015)=10.32{AA}, {sigma}(Fe5270)=10.19{AA}, {sigma}(Fe5335)=10.22{AA}, {sigma}(Mg_2_)=10.004mag, and {sigma}(Mg_b_)=10.19{AA}. This is about a factor of 2 better than the corresponding theoretical indices from the synthetic spectra, the latter being a consequence of the intrinsic limitations in the input physics, as discussed by Chavez et al. (1997, Cat. <J/A+AS/126/267>).
- ID:
- ivo://CDS.VizieR/J/ApJ/673/999
- Title:
- Supernova and host galaxies metallicities
- Short Name:
- J/ApJ/673/999
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We investigate how the different types of supernovae are relatively affected by the metallicity of their host galaxy. We match the SAI supernova catalog to the SDSS DR4 catalog of star-forming galaxies with measured metallicities. These supernova host galaxies span a range of oxygen abundance from 12+log(O/H)=7.9 to 9.3 (~0.1-2.7 solar) and a range in absolute magnitude from M_B_=-15.2 to -22.2. To reduce the various observational biases, we select a subsample of well-characterized supernovae in the redshift range from 0.01 to 0.04, which leaves us with 58 SNe II, 19 SNe Ib/c, and 38 SNe Ia.
- ID:
- ivo://CDS.VizieR/J/AJ/149/157
- Title:
- Surface intensity profiles for 10 M33 globular clusters
- Short Name:
- J/AJ/149/157
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- In this paper, we present the properties of 10 halo globular clusters (GCs) with luminosities L~=5-7x10^5^L_{sun}_ in the Local Group galaxy M33 using images from the Hubble Space Telescope WFPC2 in the F555W and F814W bands. We obtained the ellipticities, position angles, and surface brightness profiles for each GC. In general, the ellipticities of the M33 sample clusters are similar to those of the M31 clusters. The structural and dynamical parameters are derived by fitting the profiles to three different models combined with mass-to-light ratios (M/L values) from population-synthesis models. The structural parameters include core radii, concentration, half-light radii, and central surface brightness. The dynamical parameters include the integrated cluster mass, integrated binding energy, central surface mass density, and predicted line of sight velocity dispersion at the cluster center. The velocity dispersions of the four clusters predicted here agree well with the observed dispersions by Larsen et al. The results here showed that the majority of the sample halo GCs are better fitted by both the King model and the Wilson model than the Sersic model. In general, the properties of the clusters in M33, M31, and the Milky Way fall in the same regions of parameter spaces. The tight correlations of cluster properties indicate a "fundamental plane" for clusters, which reflects some universal physical conditions and processes operating at the epoch of cluster formation.
- ID:
- ivo://CDS.VizieR/J/AJ/161/134
- Title:
- Survey of stellar & planetary comp. within 25pc
- Short Name:
- J/AJ/161/134
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We explore the impact of outer stellar companions on the occurrence rate of giant planets detected with radial velocities. We searched for stellar and planetary companions to a volume-limited sample of solar-type stars within 25pc. Using adaptive optics imaging observations from the Lick 3m and Palomar 200" Telescopes, we characterized the multiplicity of our sample stars, down to the bottom of the main sequence. With these data, we confirm field star multiplicity statistics from previous surveys. We additionally combined three decades of radial velocity (RV) data from the California Planet Search with newly collected RV data from Keck/HIRES and the Automated Planet Finder/Levy Spectrometer to search for planetary companions in these same systems. Using an updated catalog of both stellar and planetary companions, as well as detailed injection/recovery tests to determine our sensitivity and completeness, we measured the occurrence rate of planets among the single and multiple-star systems. We found that planets with masses in the range of 0.1-10M_J_ and with semimajor axes of 0.1-10au have an occurrence rate of 0.18_-0.03_^+0.04^ planets per star when they orbit single stars and an occurrence rate of 0.12{+/-}0.04 planets per star when they orbit a star in a binary system. Breaking the sample down by the binary separation, we found that only one planet-hosting binary system had a binary separation <100au, and none had a separation <50au. These numbers yielded planet occurrence rates of 0.20_-0.06_^+0.07^ planets per star for binaries with separation aB>100au and 0.04_-0.02_^+0.04^ planets per star for binaries with separation aB<100au. The similarity in the planet occurrence rate around single stars and wide primaries implies that wide binary systems should actually host more planets than single-star systems, since they have more potential host stars. We estimated a system-wide planet occurrence rate of 0.3 planets per wide binary system for binaries with separations aB>100au. Finally, we found evidence that giant planets in binary systems have a different semimajor-axis distribution than their counterparts in single-star systems. The planets in the single-star sample had a significantly higher occurrence rate outside of 1au than inside 1au by nearly 4{sigma}, in line with expectations that giant planets are most common near the snow line. However, the planets in the wide binary systems did not follow this distribution, but rather had equivalent occurrence rates interior and exterior to 1au. This may point to binary-mediated planet migration acting on our sample, even in binaries wider than 100au.
- ID:
- ivo://CDS.VizieR/J/A+A/556/A150
- Title:
- SWEETCat I. Stellar parameters for host stars
- Short Name:
- J/A+A/556/A150
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- In this paper we present new precise atmospheric parameters for stars with planets. We then take the opportunity to present a new catalogue of stellar parameters for FGK and M stars with planets detected by radial velocity, transit, and astrometry programs. Stellar atmospheric parameters and masses for the sample were derived assuming LTE and using high resolution and high signal-to-noise spectra. The methodology used is based on the measurement of equivalent widths for a list of iron lines and making use of iron ionization and excitation equilibrium principles. For the catalog, and whenever possible, we used parameters derived in previous works published by our team, using well defined methodologies for the derivation of stellar atmospheric parameters. This set of parameters amounts to over 65% of all planet host stars known, including more than 90% of all stars with planets discovered through radial velocity surveys. For the remaining targets, stellar parameters were collected from the literature.
1347. SWEET-Cat updated
- ID:
- ivo://CDS.VizieR/J/A+A/620/A58
- Title:
- SWEET-Cat updated
- Short Name:
- J/A+A/620/A58
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Exoplanets have now been proven to be very common. The number of its detections continues to grow following the development of better instruments and missions. One key step for the understanding of these worlds is their characterization, which mostly depend on their host stars. We perform a significant update of the Stars With ExoplanETs CATalog (SWEET-Cat), a unique compilation of precise stellar parameters for planet-host stars provided for the exoplanet community. We made use of high-resolution spectra for planet-host stars, either observed by our team or found in several public archives. The new spectroscopic parameters were derived for the spectra following the same homogeneous process (ARES+MOOG). The host star parameters were then merged together with the planet properties listed in exoplanet.eu to perform simple data analysis. We present new spectroscopic homogeneous parameters for 106 planet-host stars. Sixty-three planet hosts are also reviewed with new parameters. We also show that there is a good agreement between stellar parameters derived for the same star but using spectra obtained from different spectrographs. The planet-metallicity correlation is reviewed showing that the metallicity distribution of stars hosting low-mass planets (below 30M_{sun}_) is indistinguishable from that from the solar neighborhood sample in terms of metallicity distribution.
- ID:
- ivo://CDS.VizieR/J/ApJS/248/21
- Title:
- Swift long gamma-ray bursts
- Short Name:
- J/ApJS/248/21
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The exact relationship between the long gamma-ray burst (LGRB) rate and the cosmic star formation rate (CSFR) is essential for using LGRBs as cosmological probes. In this work, we collect a large sample composed of 371 Swift LGRBs with known redshifts and prompt emission properties. We first compare the rest-frame prompt properties of these bursts in different redshift bins, finding negligible redshift evolution of the luminosity of LGRBs with L_iso_>~10^51^erg/s between z~1 and z~4. Then, by utilizing the CSFR obtained from the large-scale cosmological hydrodynamical simulation, the Illustris simulation, we calculate the cumulative redshift distribution of LGRBs under different metallicity thresholds. After comparing with our sample, we find that the predictions with a moderate threshold between 0.3Z_{sun}_<=Z_th_<=1.0Z_{sun}_ are consistent with the sample between redshift 0<z<3, while at higher redshifts, between 3<z<5, all metallicity thresholds fit the data well. When changing to an empirical model based on observations, the predictions show similar results as well. After comparing with the metallicity distribution of the observed LGRB host galaxies between 0<z<1, we confirm that the production of LGRBs in galaxies with super-solar metallicity is suppressed. Nevertheless, considering that a significant fraction of stars are born in sub-solar metallicity environments at z>~3, we suggest that, as a first approximation, LGRBs can be used as direct tracers of the CSFR in this redshift range.
- ID:
- ivo://CDS.VizieR/J/AJ/158/35
- Title:
- Swift UVOT Stars Survey. III. Galactic open clusters
- Short Name:
- J/AJ/158/35
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- As part of the Swift/Ultraviolet-Optical Telescope Stars Survey, we present near-ultraviolet (NUV; 3000-1700 {AA}) point-source photometry for 103 Galactic open clusters. These data, taken over the span of the mission, provide a unique and unprecedented set of NUV point-source photometry on simple stellar populations. After applying a membership analysis fueled mostly by Gaia DR2 (Cat. I/345) proper motions, we find that 49 of these 103 have clear precise color-magnitude diagrams (CMDs) amenable to investigation. We compare the CMDs to theoretical isochrones and find good agreement between the theoretical isochrones and the CMDs. The exceptions are the fainter parts of the main sequence and the red giant branch in the uvw2-uvw1 CMDs, which is most likely due to either the difficulty of correcting for the red leak in the uvw2 filter or limitations in our understanding of UV opacities for cool stars. For the most part, our derived cluster parameters - age, distance, and reddening - agree with the consensus literature, but we find a few clusters that warrant substantial revision from literature values, notably NGC 2304, NGC 2343, NGC 2360, NGC 2396, NGC 2428, NGC 2509, NGC 2533, NGC 2571, NGC 2818, Collinder 220, and NGC 6939. A number of these are clusters in the third Galactic quadrant, where previous studies may have mistaken the disk sequence for the cluster. However, the Gaia DR2 proper motions clearly favor a different sequence. A number of clusters also show white dwarf and blue straggler sequences. We confirm the presence of extended main-sequence turnoffs in NGC 2360 and NGC 2818 and show hints of them in a number of other clusters that may warrant future spectroscopic study. Most of the clusters in the study have low extinction, and the rest are well fit by a "Milky Way-like" extinction law. However, Collinder 220 hints at a possible "LMC-like" extinction law. We finally provide a comprehensive point-source catalog to the community as a tool for future investigation.
- ID:
- ivo://CDS.VizieR/J/ApJ/634/1319
- Title:
- Synthetic Lick indices of alpha-enhanced stars
- Short Name:
- J/ApJ/634/1319
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- A sample of 119 F, G, and K solar neighborhood stars, selected under the condition [Fe/H]>0.00, is investigated in order to detect which of them, if any, present {alpha}-enhanced characteristics. According to the kinematics, the sample represents stars of the thin-disk component of the Galaxy.
