- ID:
- ivo://CDS.VizieR/J/A+A/604/L4
- Title:
- HAT-P-4 and TYC 2569-744-1 abundances and spectra
- Short Name:
- J/A+A/604/L4
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We explore condensation temperature Tc trends and the Li content in the binary system HAT-P-4, to study the possible chemical signature of planet formation. The star HAT-P-4 hosts a hot Jupiter planet detected by transits, while its stellar companion does not have any detected planets. We derived the fundamental parameters and abundances using the differential method. HAT-P-4 is found to be about 0.1dex more metal rich than its companion; it is enhanced in refractory elements and presents a higher Lithium content. We propose a scenario of a possible rocky planet engulfment in HAT-P-4, which explains the higher metallicity, the higher Li content, and the negative Tc trend we detected.
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Search Results
- ID:
- ivo://CDS.VizieR/J/AJ/155/114
- Title:
- HAT-TR-318-007: a double-lined M dwarf binary
- Short Name:
- J/AJ/155/114
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We report the discovery by the HATNet survey of HAT-TR-318-007, a P=3.34395390+/-0.00000020 day period detached double-lined M dwarf binary with total secondary eclipses. We combine radial velocity (RV) measurements from TRES/FLWO 1.5 m and time-series photometry from HATNet, FLWO 1.2 m, BOS 0.8 m, and NASA K2 Campaign 5, to determine the masses and radii of the component stars: M_A_=0.448+/-0.011 M_{sun}_^N^, M_B_=0.2721_-0.0042_^+0.0041^ M_{sun}_^N^, R_A_=0.4548_-0.0036_^+0.0035^ R_{sun}_^N^, and R_B_=0.2913_-0.0024_^+0.0023^ R_{sun}_^N^. We obtained a FIRE/Magellan near-infrared spectrum of the primary star during a total secondary eclipse, and we use this to obtain disentangled spectra of both components. We determine spectral types of ST_A_=M3.71+/-0.69 and ST_B_=M5.01+/-0.73 and effective temperatures of T_eff,A_=3190+/-110 K and T_eff,B_=3100+/-110 K for the primary and secondary star, respectively. We also measure a metallicity of [Fe/H]=+0.298+/-0.080 for the system. We find that the system has a small, but significant, nonzero eccentricity of 0.0136+/-0.0026. The K2 light curve shows a coherent variation at a period of 3.41315_-0.00032_^+0.00030^ days, which is slightly longer than the orbital period, and which we demonstrate comes from the primary star. We interpret this as the rotation period of the primary. We perform a quantitative comparison between the Dartmouth stellar evolution models and the seven systems, including HAT-TR-318-007, that contain M dwarfs with 0.2 M_{sun}_^N^<M<0.5 M_{sun}_^N^, have metallicity measurements, and have masses and radii determined to better than 5% precision. Discrepancies between the predicted and observed masses and radii are found for three of the systems.
- ID:
- ivo://CDS.VizieR/J/ApJ/829/116
- Title:
- H-band spectroscopic analysis of 25 bright M31 GCs
- Short Name:
- J/ApJ/829/116
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Chemical abundances are presented for 25 M31 globular clusters (GCs), based on moderately high resolution (R=22500) H-band integrated light (IL) spectra from the Apache Point Observatory Galactic Evolution Experiment (APOGEE). Infrared (IR) spectra offer lines from new elements, lines of different strengths, and lines at higher excitation potentials compared to the optical. Integrated abundances of C, N, and O are derived from CO, CN, and OH molecular features, while Fe, Na, Mg, Al, Si, K, Ca, and Ti abundances are derived from atomic features. These abundances are compared to previous results from the optical, demonstrating the validity and value of IR IL analyses. The CNO abundances are consistent with typical tip of the red giant branch stellar abundances but are systematically offset from optical Lick index abundances. With a few exceptions, the other abundances agree between the optical and the IR within the 1{sigma} uncertainties. The first integrated K abundances are also presented and demonstrate that K tracks the {alpha} elements. The combination of IR and optical abundances allows better determinations of GC properties and enables probes of the multiple populations in extragalactic GCs. In particular, the integrated effects of the Na/O anticorrelation can be directly examined for the first time.
- ID:
- ivo://CDS.VizieR/J/A+A/635/A4
- Title:
- HCN-to-HNC intensity ratio
- Short Name:
- J/A+A/635/A4
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The gas kinetic temperature (TK) determines the physical and chemical evolution of the interstellar medium (ISM). However, obtaining reliable TK estimates usually requires expensive observations including the combination of multi-line analysis and dedicated radiative transfer calculations. This work explores the use of HCN and HNC observations, and particularly the I(HCN)-to-I(HNC) intensity ratio (I(HCN)/I(HNC)) of their J=1-0 lines, as direct probe of the gas kinetic temperature in the molecular ISM. We obtained a new set of large-scale observations of the HCN and HNC (1-0) lines throughout the Integral Shape Filament (ISF) in Orion. In combination with ancillary gas and dust temperature measurements, we find a systematic temperature dependence of the observed I(HCN)-to-I(HNC) intensity ratio throughout our maps. Additional comparisons with chemical models demonstrate that these observed I(HCN)/I(HNC) variations are driven by the effective destruction and isomerization mechanisms of HNC under low-energy barriers. The observed variations of I(HCN)/I(HNC) with TK can be described with a two-part linear function. This empirical calibration is then used to create a temperature map of the entire ISF. Comparisons with similar dust temperature measurements in this cloud, as well as in other regions and galactic surveys, validate this simple technique for obtaining direct estimates of the gas kinetic temperature in a wide range of physical conditions and scales with an optimal working range between 15K<TK<=40K. Both observations and models demonstrate the strong sensitivity of the I(HCN)/I(HNC) ratio to the gas kinetic temperature. Since these lines are easily obtained in observations of local and extragalactic sources, our results highlight the potential use of this observable as new chemical thermometer for the ISM.
- ID:
- ivo://CDS.VizieR/J/AJ/134/321
- Title:
- H{delta} line in globular clusters
- Short Name:
- J/AJ/134/321
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a cautionary study exploring the reliability of the H{delta} line in the integrated spectra of galaxies for determining galaxy ages. Our database consists of the observed integrated spectra of ~120 early-type galaxies, 7 metal-rich globular clusters in M31 and the Galactic globular cluster 47 Tuc, and the open cluster M67. We have measured H{delta} using index definitions designed to assess contamination from the CN molecule in and around H{delta} by choosing combinations of bandpasses that both avoid and include a region of CN molecular lines redward of H{delta}. We find systematic differences in the ages derived from H{delta} measurements among the various definitions when extracting ages from H{delta} in old stellar populations with enhanced CN bands due to nonsolar abundance ratios. We propose that neighboring CN lines have a strong effect on pseudocontinuum and central bandpass levels. For stellar populations that have nonsolar abundance ratios in C and/or N, population synthesis models that do not account for abundance ratio variations cannot accurately reproduce the CN 4216{AA} band, which leads to a corresponding inaccuracy in reproducing the various H{delta} indices. Hence, caution must be used when extracting galaxy ages from the H{delta} line in old stellar populations with significant nonsolar abundance ratios.
- ID:
- ivo://CDS.VizieR/J/AJ/159/9
- Title:
- HD 150382 lithium-rich star at the early-AGB stage
- Short Name:
- J/AJ/159/9
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We report the discovery of a lithium-rich giant, HD 150382, a post-red-giant-branch clump star. The atmospheric parameters, the chemical abundances for 17 elements, and the isotopic ratio ^12^C/^13^C were determined using the equivalent width and the spectral synthesis methods. The lithium abundance was determined via spectral synthesis of the Li I resonance doublet at {lambda} 6708 yielding log{epsilon}(Li)_NLTE_=2.55. The excited-state line at {lambda} 6104 also was analyzed. In addition, we have used theoretical evolutionary tracks to determine the mass and luminosity of HD 150382 and compare it with other well-known lithium-rich giants in the literature. Our results show that HD 150382 is a slowly rotating K-giant star having near-solar metallicity. We also show that HD 150382 is not s-process enriched, which is in agreement with its evolutionary status. Finally, based on the abundance results, we study the possible scenarios of the lithium enrichment.
- ID:
- ivo://CDS.VizieR/J/ApJ/786/14
- Title:
- He abundances in M30 and NGC 6397
- Short Name:
- J/ApJ/786/14
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the helium abundance of the two metal-poor clusters M30 and NGC 6397. Helium estimates have been obtained by using the high-resolution spectrograph FLAMES at the European Southern Observatory Very Large Telescope and by measuring the He I line at 4471 {AA} in 24 and 35 horizontal branch (HB) stars in M30 and NGC 6397, respectively. This sample represents the largest data set of He abundances collected so far in metal-poor clusters. The He mass fraction turns out to be Y=0.252+/-0.003 ({sigma}=0.021) for M30 and Y=0.241+/-0.004 ({sigma}=0.023) for NGC 6397. These values are fully compatible with the cosmological abundance, thus suggesting that the HB stars are not strongly enriched in He. The small spread of the Y distributions are compatible with those expected from the observed main sequence splitting. Finally, we find a hint of a weak anticorrelation between Y and [O/Fe] in NGC 6397 in agreement with the prediction that O-poor stars are formed by (He-enriched) gas polluted by the products of hot proton-capture reactions.
- ID:
- ivo://CDS.VizieR/J/ApJ/689/1031
- Title:
- Heavy element abundances in giant stars
- Short Name:
- J/ApJ/689/1031
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a comprehensive abundance analysis of 27 heavy elements in bright giant stars of the globular clusters M4 and M5 based on high-resolution, high signal-to-noise ratio spectra obtained with the Magellan Clay Telescope. We confirm and expand on previous results for these clusters by showing that (1) all elements heavier than, and including, Si have constant abundances within each cluster, (2) the elements from Ca to Ni have indistinguishable compositions in M4 and M5, (3) Si, Cu, Zn, and all s-process elements are approximately 0.3dex overabundant in M4 relative to M5, and (4) the r-process elements Sm, Eu, Gd, and Th are slightly overabundant in M5 relative to M4. The cluster-to-cluster abundance differences for Cu and Zn are intriguing, especially in light of their uncertain nucleosynthetic origins. We confirm that stars other than Type Ia supernovae must produce significant amounts of Cu and Zn at or below the clusters' metallicities. If intermediate-mass AGB stars or massive stars are responsible for the Cu and Zn enhancements in M4, the similar [Rb/Zr] ratios and (preliminary) Mg isotope ratios in both clusters may be problematic for either scenario. For the elements from Ba to Hf, we assume that the s- and r-process contributions are scaled versions of the solar s- and r-process abundances. We quantify the relative fractions of s- and r-process material for each cluster and show that they provide an excellent fit to the observed abundances.
- ID:
- ivo://CDS.VizieR/J/AJ/142/22
- Title:
- Heavy-element dispersion in M92
- Short Name:
- J/AJ/142/22
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Dispersion among the light elements is common in globular clusters (GCs), while dispersion among heavier elements is less common. We present detection of r-process dispersion relative to Fe in 19 red giants of the metal-poor GC M92. Using spectra obtained with the Hydra multi-object spectrograph on the WIYN Telescope at Kitt Peak National Observatory, we derive differential abundances for 21 species of 19 elements.
- ID:
- ivo://CDS.VizieR/J/ApJ/724/975
- Title:
- Heavy elements abundances of metal-poor stars
- Short Name:
- J/ApJ/724/975
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- To better characterize the abundance patterns produced by the r-process, we have derived new abundances or upper limits for the heavy elements zinc (Zn, Z=30), yttrium (Y, Z=39), lanthanum (La, Z=57), europium (Eu, Z=63), and lead (Pb, Z=82). Our sample of 161 metal-poor stars includes new measurements from 88 high-resolution and high signal-to-noise spectra obtained with the Tull Spectrograph on the 2.7m Smith Telescope at the McDonald Observatory, and other abundances are adopted from the literature. We use models of the s-process in asymptotic giant branch stars to characterize the high Pb/Eu ratios produced in the s-process at low metallicity, and our new observations then allow us to identify a sample of stars with no detectable s-process material.
