- ID:
- ivo://CDS.VizieR/J/ApJ/897/183
- Title:
- Chemical abundances of 3 stars in Grus II galaxy
- Short Name:
- J/ApJ/897/183
- Date:
- 15 Mar 2022 04:18:06
- Publisher:
- CDS
- Description:
- We present a detailed abundance analysis of the three brightest member stars at the top of the giant branch of the ultrafaint dwarf (UFD) galaxy GrusII. All stars exhibit a higher than expected [Mg/Ca] ratio compared to metal-poor stars in other UFD galaxies and in the Milky Way (MW) halo. Nucleosynthesis in high-mass (>=20M{sun}) core-collapse supernovae has been shown to create this signature. The abundances of this small sample (three) stars suggests the chemical enrichment of GrusII could have occurred through substantial high-mass stellar evolution, and is consistent with the framework of a top-heavy initial mass function. However, with only three stars it cannot be ruled out that the abundance pattern is the result of a stochastic chemical enrichment at early times in the galaxy. The most metal-rich of the three stars also possesses a small enhancement in rapid neutron-capture (r-process) elements. The abundance pattern of the r-process elements in this star matches the scaled r-process pattern of the solar system and r-process enhanced stars in other dwarf galaxies and in the MW halo, hinting at a common origin for these elements across a range of environments. All current proposed astrophysical sites of r-process element production are associated with high- mass stars, thus the possible top-heavy initial mass function of GrusII would increase the likelihood of any of these events occurring. The time delay between the {alpha} and r-process element enrichment of the galaxy favors a neutron star merger as the origin of the r-process elements in GrusII.
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Search Results
- ID:
- ivo://CDS.VizieR/III/58
- Title:
- Chemical elements in peculiar stellar spectra
- Short Name:
- III/58
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- A systematic search of 27 journals, IAU Symposia, and Colloquia has yielded this catalogue of identifications of chemical species in peculiar spectra Ap, Bp and Am generally. Abundance surveys were only searched if they included element identification lists.
- ID:
- ivo://CDS.VizieR/J/A+A/459/871
- Title:
- Chemically peculiar stars in the LMC
- Short Name:
- J/A+A/459/871
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present high precision photometric Delta a observations of 417 objects in NGC 2136/7 and its surrounding field, of which five turned out to be bona fide magnetic CP stars. In addition, we discovered two Be/Ae stars. This intermediate band photometric system samples the depth of the 520nm flux depression by comparing the flux at the center with the adjacent regions with bandwidths of 11nm to 23nm. The Delta a photometric system is most suitable for detecting CP2 stars with high efficiency, but is also capable of detecting a small percentage of non-magnetic CP objects. From our investigations of NGC 1711, NGC 1866, NGC 2136/7, their surroundings, and one independent field of the LMC population, we derive an occurrence of classical chemically peculiar stars of 2.2(6)% in the LMC, which is only half the value found in the Milky Way. The mass and age distribution of the photometrically detected CP stars is not different from that of similar objects in galactic open clusters.
- ID:
- ivo://CDS.VizieR/J/A+A/597/A55
- Title:
- Corot photometry of TYC 455-791-1
- Short Name:
- J/A+A/597/A55
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We report the discovery and analysis of very narrow transits in the eccentric spectroscopic binary TYC 455-791-1=HSS 348 (IC 4756). We obtained high-precision CoRoT photometry over two long runs and multi-epoch high-resolution echelle spectroscopy and imaging with STELLA. Standard radial-velocity extraction, spectrum synthesis, Fourier analysis, and light-curve inversions are applied to the data. HSS 348 is found to be an eccentric (e=0.18) double-lined spectroscopic binary with a period of 12.47 d in which at least the primary component is a peculiar B star of the HgMn class. The orbital elements are such that the system undergoes a grazing eclipse with the primary in front but no secondary eclipse. The out-of-eclipse light variations show four nearly equidistant but unequal minima stable in shape and amplitude throughout our observations. Their individual photometric periods are all harmonics of the same fundamental period which happens to agree with the transit period to within the errors. We interpret the fundamental period to be the rotation period of at least one if not both stars due to surface inhomogeneities. Due to the non-zero eccentricity of the orbit the two components are rotating sub-synchronously. It appears that HSS 348 is not a member of the IC 4756 cluster but a background B8+B8.5 binary system. Its sharp eclipses every 12.47 days just mimic a small-body transit but are in reality the grazing eclipses of a B-star binary and thus a classical false positive. The system seems to be pre-main sequence with the primary possibly just arrived on the ZAMS. The light curve with four unequal minima can be explained with four cool spots of different size equidistantly positioned in longitude. Our data do not allow to uniquely assign the spots to either of the two stars.
- ID:
- ivo://CDS.VizieR/J/A+AS/108/595
- Title:
- CP2 SrCrEu stars light variation
- Short Name:
- J/A+AS/108/595
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- (no description available)
36. CP stars
- ID:
- ivo://CDS.VizieR/J/A+AS/107/353
- Title:
- CP stars
- Short Name:
- J/A+AS/107/353
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Fine analyses of the silicon star HD 43819 and the CP star HD 147550 are presented using ATLAS9 model atmospheres whose predictions fit the optical region spectrophotometry and H{gamma} profiles and have the same bulk metallicity as the deduced abundances. For HD 43819 except for scandium and nickel, the derived abundances of the iron peak elements are around 10 times solar while those of the rare earths are about 1000 times solar. The lighter elements are generally underabundant except for silicon and calcium which are overabundant. HD 147550 is helium and calcium poor; carbon, magnesium, aluminum, scandium, titanium, and iron normal; and sulfur, chromium, manganese, nickel, strontium, zirconium, barium, europium, and mercury rich. It is a nonmagnetic CP star intermediate between the HgMn and the hot Am stars.
- ID:
- ivo://CDS.VizieR/J/MNRAS/487/5922
- Title:
- CP stars catalog (roAp, He-weak, He-rich)
- Short Name:
- J/MNRAS/487/5922
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- To enlarge our data base of chemically peculiar stars, we compiled published data concerning the He-weak and He-rich stars observed by high-resolution spectroscopy techniques during last decades. Twenty He-weak and 28 He-rich stars have been added to the data base. We have also distinguished roAp stars from stars previously identified as Ap stars. To deepen our knowledge on statistical overview of the abundance anomalies versus the physical parameters of stars, we compared our data with previous compilations. We applied statistical tests on our data and found interesting correlations for effective temperature and surface gravity for all type of stars and a few correlations for projected rotation velocity only for He-rich stars. Because of the lack of the data, we could not check whether being a member of binary system is affecting on chemical peculiarities of those stars.
38. CP stars in LMC
- ID:
- ivo://CDS.VizieR/J/MNRAS/362/1025
- Title:
- CP stars in LMC
- Short Name:
- J/MNRAS/362/1025
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- With the aim to corroborate the result of a search for chemically peculiar stars in the Large Magellanic Cloud (LMC), we present measurements obtained from CCD imaging of two fields, one containing a young open cluster (NGC 1711). ************************************************************************** * * * Sorry, but the author(s) never supplied the tabular material * * announced in the paper * * * **************************************************************************
- ID:
- ivo://CDS.VizieR/J/other/AstBu/71.302
- Title:
- CP stars magnetic fields catalog (2009)
- Short Name:
- J/other/AstBu/71
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the results of measuring longitudinal magnetic fields (B_e), rotation velocities (v_e_sini), and radial velocities (V_r_) of 44 stars observed with the Main Stellar Spectrograph (MSS) of the 6-m BTA telescope of the Special Astrophysical Observatory in 2009. Observations of standard stars without magnetic fields confirm the absence of systematic errors capable of introducing distortions into the longitudinal-field measurement results. In this work we comment on the results for each of the stars.
- ID:
- ivo://CDS.VizieR/J/other/AstBu/69.427
- Title:
- CP stars magnetic fields catalog (2007)
- Short Name:
- J/other/AstBu/69
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- This catalog presents the results of magnetic field measurements for 39 chemically peculiar and 3 normal main sequence stars used as standard stars. Observations were carried out with the Main Stellar Spectrograph of the Russian 6-m telescope during 2007. The accuracy analysis for the longitudinal magnetic field measurements of the stars confirms that the systematic errors do not exceed 10-20G and are within the quoted limits. The absence of significant instrumental deviations follows from the measurements of theBD CP stars with well-known B_e_ variation curves.
