- ID:
- ivo://CDS.VizieR/J/MNRAS/495/3961
- Title:
- Planet-hosting stars chemical compositions
- Short Name:
- J/MNRAS/495/3961
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a line-by-line differential analysis of a sample of 16 planet-hosting stars and 68 comparison stars using high-resolution, high signal-to-noise ratio spectra gathered using Keck. We obtained accurate stellar parameters and high-precision relative chemical abundances with average uncertainties in Teff, logg, [Fe/H], and [X/H] of 15K, 0.034cm/s^2^, 0.012dex, and 0.025dex, respectively. For each planet host, we identify a set of comparison stars and examine the abundance differences (corrected for Galactic chemical evolution effect) as a function of the dust condensation temperature, Tcond, of the individual elements. While we confirm that the Sun exhibits a negative trend between abundance and Tcond, we also confirm that the remaining planet hosts exhibit a variety of abundance-Tcond trends with no clear dependence upon age, metallicity, or Teff. The diversity in the chemical compositions of planet-hosting stars relative to their comparison stars could reflect the range of possible planet-induced effects present in these planet hosts, from the sequestration of rocky material (refractory poor) to the possible ingestion of planets (refractory rich). Other possible explanations include differences in the time-scale, efficiency and degree of planet formation, or inhomogeneous chemical evolution. Although we do not find an unambiguous chemical signature of planet formation among our sample, the high-precision chemical abundances of the host stars are essential for constraining the composition and structure of their exoplanets.
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Search Results
- ID:
- ivo://CDS.VizieR/J/ApJ/855/107
- Title:
- PMAS Integral-field SN hosts COmpilation (PISCO)
- Short Name:
- J/ApJ/855/107
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the PMAS/PPak Integral-field Supernova hosts COmpilation (PISCO), which comprises integral field spectroscopy (IFS) of 232 supernova (SN) host galaxies that hosted 272 SNe, observed over several semesters with the 3.5m telescope at the Calar Alto Observatory (CAHA). PISCO is the largest collection of SN host galaxies observed with wide-field IFS, totaling 466347 individual spectra covering a typical spatial resolution of ~380pc. Focused studies regarding specific SN Ia-related topics will be published elsewhere; this paper aims to present the properties of the SN environments, using stellar population (SP) synthesis, and the gas-phase interstellar medium, providing additional results separating stripped-envelope SNe into their subtypes. With 11270 HII regions detected in all galaxies, we present for the first time a statistical analysis of HII regions, which puts HII regions that have hosted SNe in context with all other star-forming clumps within their galaxies. SNe Ic are associated with environments that are more metal-rich and have higher EW(H{alpha}) and higher star formation rate within their host galaxies than the mean of all HII regions detected within each host. This in contrast to SNe IIb, which occur in environments that are very different compared to other core-collapse SNe types. We find two clear components of young and old SPs at SNe IIn locations. We find that SNe II fast decliners tend to explode at locations where the {Sigma}SFR is more intense. Finally, we outline how a future dedicated IFS survey of galaxies in parallel to an untargeted SN search would overcome the biases in current environmental studies.
- ID:
- ivo://CDS.VizieR/J/AJ/121/1040
- Title:
- PMS members of upper Scorpius OB association
- Short Name:
- J/AJ/121/1040
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the results of a large intermediate-resolution spectroscopic survey for pre-main-sequence (PMS) stars in the Upper Scorpius OB association, the nearest region of recent massive star formation. Utilizing the 2dF multiobject spectrograph at the Anglo-Australian Telescope, we obtained spectra of 576 stars with magnitudes 12.5<=R<=16.5 in a 6{deg}^2^ area in Upper Scorpius. Among these objects we were able to identify 98 new PMS stars, nearly all of them M-type stars, by their strong lithium absorption lines. We place the new PMS stars into the H-R diagram and find that their ages agree well with the mean age of 5Myr determined in our earlier investigation based on a smaller sample of stars. The number of low-mass (0.1M_{sun}_<~M*<~0.5M_{sun}) members is at least as high as expected from the known number of high-mass (M*>~3M_{sun}_) association members and from recent determinations of the field star initial mass function. Thus, there is no deficit of low-mass stars in Upper Scorpius.
- ID:
- ivo://CDS.VizieR/J/ApJ/769/40
- Title:
- Potassium abundance in red giants of GCs
- Short Name:
- J/ApJ/769/40
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Two independent studies recently uncovered two distinct populations among giants in the distant, massive globular cluster (GC) NGC 2419. One of these populations has normal magnesium (Mg) and potassium (K) abundances for halo stars: enhanced Mg and roughly solar K. The other population has extremely depleted Mg and very enhanced K. To better anchor the peculiar NGC 2419 chemical composition, we have investigated the behavior of K in a few red giant branch stars in NGC 6752, NGC 6121, NGC 1904, and {omega} Cen. To verify that the high K abundances are intrinsic and not due to some atmospheric features in giants, we also derived K abundances in less evolved turn-off and subgiant stars of clusters 47 Tuc, NGC 6752, NGC 6397, and NGC 7099. We normalized the K abundance as a function of the cluster metallicity using 21 field stars analyzed in a homogeneous manner. For all GCs of our sample, the stars lie in the K-Mg abundance plane on the same locus occupied by the Mg-normal population in NGC 2419 and by field stars. This holds for both giants and less-evolved stars. At present, NGC 2419 seems unique among GCs.
- ID:
- ivo://CDS.VizieR/J/ApJ/745/74
- Title:
- Pre-maximum spectra of type Ia SNe
- Short Name:
- J/ApJ/745/74
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The presence of unburned material in the ejecta of normal Type Ia supernovae (SNe Ia) is investigated using early-time spectroscopy obtained by the Carnegie Supernova Project. The tell-tale signature of pristine material from a C+O white dwarf progenitor star is the presence of carbon, as oxygen is also a product of carbon burning. The most prominent carbon lines in optical spectra of SNe Ia are expected to arise from CII. We find that at least 30% of the objects in the sample show an absorption at {approx}6300{AA} which is attributed to CII{lambda}6580. An alternative identification of this absorption as H{alpha} is considered to be unlikely. These findings imply a larger incidence of carbon in SNe Ia ejecta than previously noted.
- ID:
- ivo://CDS.VizieR/J/ApJS/216/33
- Title:
- Probing the Local Bubble with DIBs. III.
- Short Name:
- J/ApJS/216/33
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present new high signal-to-noise ratio (S/N) observations of the diffuse interstellar bands (DIBs) in the Local Bubble and its surroundings. We observed 432 sightlines and obtain the equivalent widths of the {lambda}5780 and {lambda}5797{AA} DIBs up to a distance of ~200pc. All of the observations were carried out using the Intermediate Dispersion Spectrograph on the 2.5m Isaac Newton Telescope, during three years, to reach a minimum S/N of ~2000. All of the {lambda}5780 and {lambda}5797 absorptions are presented in this paper and we tabulate the observed values of the interstellar parameters, {lambda}5780, {lambda}5797, Na ID_1_, and Na ID_2_, including the uncertainties.
- ID:
- ivo://CDS.VizieR/J/MNRAS/469/3163
- Title:
- Properties of BAL quasars
- Short Name:
- J/MNRAS/469/3163
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We investigate broad absorption line (BAL) disappearance and emergence using a 470 BAL-quasar sample over <=0.10-5.25 rest-frame years with at least three spectroscopic epochs for each quasar from the Sloan Digital Sky Survey. We identify 14 disappearing BALs over <=1.73-4.62 rest-frame years and 18 emerging BALs over <=1.46-3.66 rest-frame years associated with the CIV{lambda}{lambda}1548,1550 and/or SiIV{lambda}{lambda}1393,1402 doublets, and report on their variability behaviour. BAL quasars in our data set exhibit disappearing/emerging C IV BALs at a rate of 2.3^+0.9^_-0.7_ and 3.0^+1.0^_-0.8_ per cent, respectively, and the frequency for BAL to non-BAL quasar transitions is 1.7^+0.8^_-0.6_ per cent. We detect four re-emerging BALs over <=3.88 rest-frame years on average and three re-disappearing BALs over <=4.15 rest-frame years on average, the first reported cases of these types. We infer BAL lifetimes along the line of sight to be nominally <=100-1000yr using disappearing CIV BALs in our sample. Interpretations of (re-)emerging and (re-)disappearing BALs reveal evidence that collectively supports both transverse-motion and ionization-change scenarios to explain BAL variations. We constrain a nominal CIV/SiIV BAL-outflow location of <=100pc from the central source and a radial size of >=1x10^-7^pc (0.02au) using the ionization-change scenario, and constrain a nominal outflow location of <=0.5pc and a transverse size of ~0.01pc using the transverse-motion scenario. Our findings are consistent with previous work, and provide evidence in support of BALs tracing compact flow geometries with small filling factors.
- ID:
- ivo://CDS.VizieR/J/A+A/547/A80
- Title:
- Properties of Collinder 69 low-mass members
- Short Name:
- J/A+A/547/A80
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Most observational studies conducted so far point toward brown dwarfs sharing a similar formation mechanism as the one that is accepted for low-mass stars. However, larger databases and more systematic studies are needed before strong conclusions can be reached. In this second paper of a series devoted to studying the spectroscopic properties of the Lambda Orionis star-forming region members, we study accretion, activity and rotation for a wide set of spectroscopically confirmed members of the central star cluster Collinder 69 to assess analogies and/or differences between the brown-dwarf and stellar populations of this cluster. Moreover, we present comparisons with other star-forming regions of similar and different ages to address environmental effects on our conclusions. We studied prominent photospheric lines to derive rotational velocities and emission lines to distinguish between accretion processes and chromospheric activity. In addition, we include information about disk presence and X-ray emission.
- ID:
- ivo://CDS.VizieR/J/ApJ/817/79
- Title:
- Properties of emission-line galaxies
- Short Name:
- J/ApJ/817/79
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We compare the physical and morphological properties of z~2 Ly{alpha} emitting galaxies (LAEs) identified in the HETDEX Pilot Survey and narrow band studies with those of z~2 optical emission line selected galaxies (oELGs) identified via HST WFC3 infrared grism spectroscopy. Both sets of galaxies extend over the same range in stellar mass (7.5<logM/M_{sun}_<10.5), size (0.5<R<3.0kpc), and star formation rate (~1<SFR<100M_{sun}_/yr). Remarkably, a comparison of the most commonly used physical and morphological parameters - stellar mass, half-light radius, UV slope, SFR, ellipticity, nearest neighbor distance, star formation surface density, specific SFR, [OIII] luminosity, and [OIII] equivalent width - reveals no statistically significant differences between the populations.
- ID:
- ivo://CDS.VizieR/J/PASJ/59/335
- Title:
- Properties of 160 F-K disk dwarfs/subgiants
- Short Name:
- J/PASJ/59/335
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The properties of 160 F, G, and K disk dwarfs/subgiants (including 27 planet-host stars) mostly within -0.6<~[Fe/H]<~+0.4, the Okayama Astrophysical Observatory spectrum collection of which had been made open to the public recently, were extensively investigated with particular attention to determining (1) the mass and the age with the help of theoretical stellar evolution calculations, (2) the kinematic parameters of orbital motions in the Galaxy, and (3) the abundances of 15 elements (Na, Mg, Al, Si, S, Ca, Sc, Ti, V, Cr, Mn, Co, Ni, Cu, and Zn) by analyzing the spectra in this database. The resulting characteristics are discussed in terms of several relevant topics of interest, such as a validity check for assuming LTE, the [X/Fe] vs. [Fe/H] diagram containing information on the chemical evolution of the Galactic disk, the age-metallicity-kinematics relation, and the difference/similarity between stars with and without planets.
