- ID:
- ivo://CDS.VizieR/J/AJ/152/54
- Title:
- Spectroscopy of main-belt Ch/Cgh-type asteroids
- Short Name:
- J/AJ/152/54
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- CM chondrites are the most common type of hydrated meteorites, making up ~1.5% of all falls. Whereas most CM chondrites experienced only low-temperature (~0{deg}C-120{deg}C) aqueous alteration, the existence of a small fraction of CM chondrites that suffered both hydration and heating complicates our understanding of the early thermal evolution of the CM parent body(ies). Here, we provide new constraints on the collisional and thermal history of CM-like bodies from a comparison between newly acquired spectral measurements of main-belt Ch/Cgh-type asteroids (70 objects) and existing laboratory spectral measurements of CM chondrites. It first appears that the spectral variation observed among CM-like bodies is essentially due to variations in the average regolith grain size. Second, the spectral properties of the vast majority (unheated) of CM chondrites resemble both the surfaces and the interiors of CM-like bodies, implying a "low" temperature (<300{deg}C) thermal evolution of the CM parent body(ies). It follows that an impact origin is the likely explanation for the existence of heated CM chondrites. Finally, similarly to S-type asteroids and (2) Pallas, the surfaces of large (D>100km) - supposedly primordial - Ch/Cgh-type main-belt asteroids likely expose the interiors of the primordial CM parent bodies, a possible consequence of impacts by small asteroids (D<10km) in the early solar system.
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1062. Spectroscopy of MWC 297
- ID:
- ivo://CDS.VizieR/J/A+AS/131/479
- Title:
- Spectroscopy of MWC 297
- Short Name:
- J/A+AS/131/479
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- On the basis of spectroscopic CCD material obtained at the Haute Provence Observatory, we provide line identifications and equivalent width measurements in the wavelength region 4100-8900{AA} of the spectrum of MWC 297. About two hundred features are identified, almost exclusively emission lines. Only one interstellar feature could be identified ({lambda}6613) a fact which contrasts with the eigth magnitudes of extinction found by photometrists. The spectrum of the underlying star corresponds probably to a late O or early B-type object. The cooler emission lines correspond to a spectrum of a middle A-type star. Analogies with other stars observed in this series of papers are examined.
1063. Spectroscopy of MWC 645
- ID:
- ivo://CDS.VizieR/J/A+AS/120/99
- Title:
- Spectroscopy of MWC 645
- Short Name:
- J/A+AS/120/99
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We analyse spectroscopic CCD material obtained at the Haute Provence Observatory. We provide identifications and equivalent width measurements in the wavelength region 3740-8790. About 350 emissions lines were measured and about 88 of them were identified. A comparison of our results with those of other authors is provided, as well as a table of elements identified in the spectrum of this star. The pattern of elements present is analogous to that of a late B-type star, but some exceptions are noted, such as the absence of Ne and Mg lines and the presence of K, Cu and Zr lines which appear usually in later type stars. We review the little which is known concerning this object and we also present a quantitative account of the variations in equivalent widths. The observations indicate that the spectrum is highly variable, so that in two different years only half of the lines appear on both spectra. Furthermore variations by at least a factor of two in the equivalent widths are present in many lines. The radial velocity derived from the emission lines (-76km/s) corresponds to that of the shell which probably has a velocity of about 50km/s with respect to the underlying star.
- ID:
- ivo://CDS.VizieR/J/A+AS/118/495
- Title:
- Spectroscopy of MWC 349 A
- Short Name:
- J/A+AS/118/495
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We analyse spectroscopic CCD material obtained at the Haute Provence Observatory. We provide line identifications and equivalent width measurements in the wavelength region 3700-8790A. Over 300 emission features are identified and a comparison of our results with those of other authors is provided, as well as a table of all elements which have been identified in the spectrum of the object. The pattern of elements present is analogous to that of B-type stars, but some exceptions are noted, such as the absence of C, Al and Mn. We review the present knowledge of the spectrum variability of MWC 349A. The observations indicate th at the equivalent widths of the lines of many elements vary by factors of up to two. We also provide a list of diffuse interstellar features observed. The latter lead to an average (B-V) excess of about two magnitudes, which is less than what is expected for an object having an interstellar extinction of 10-11 magnitudes.
- ID:
- ivo://CDS.VizieR/J/A+AS/128/475
- Title:
- Spectroscopy of MWC 158 = HD 50138
- Short Name:
- J/A+AS/128/475
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- On the basis of spectroscopic CCD material obtained at the Haute Provence Observatory, we provide line identifications and equivalent width measurements in the wavelength region 3738-10232 A of the spectrum of HD 50138 Over two hundred features are identified and a comparison of our results with those of other authors is provided. We also discuss the variability of the lines using equivalent widths and descriptions of the line spectrum. We attribute as a best compromise a spectral type of B 5 III. We conclude that the gaseous shell surrounding the star has a temperature of the order of 10 000K and that its distance to the star is of the order of two stellar radii. We discuss the relation of this star to others previously analyzed and warn against hasty generalizations.
- ID:
- ivo://CDS.VizieR/J/MNRAS/411/1536
- Title:
- Spectroscopy of of IC4499 red giants
- Short Name:
- J/MNRAS/411/1536
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present radial velocity and metallicity measurements for the far southern Galactic globular cluster IC 4499. We selected several hundred target red giant stars in and around the cluster from the 2MASS point source catalogue, and obtained spectra at the near-infrared calcium triplet using the AAOmega spectrograph. Observations of giants in globular clusters M4, M22 and M68 were taken to provide radial velocity and metallicity comparison objects.
- ID:
- ivo://CDS.VizieR/J/ApJS/132/37
- Title:
- Spectroscopy of Southern warm IR galaxies
- Short Name:
- J/ApJS/132/37
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- In this paper, we present high-resolution optical spectra and optical classifications from our large sample of 285 warm infrared galaxies 10^8^<L_IR_<10^12.5^L_{sun}_. We have classified these galaxies using new theoretical lines on the standard optical diagnostic diagrams. We use a theoretical extreme mixing line between the starburst and AGN regions to classify LINER galaxies and we define a theoretical boundary separating AGNs from starbursts. We find that many galaxies previously classified as LINERs appear to lie on a mixing sequence between starburst and AGN type galaxies.
- ID:
- ivo://CDS.VizieR/J/ApJ/703/1323
- Title:
- Spectroscopy of stars in the Galaxy's nuclear cluster
- Short Name:
- J/ApJ/703/1323
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We report on the structure of the nuclear star cluster in the innermost 0.16pc of the Galaxy as measured by the number density profile of late-type giants. Using laser guide star adaptive optics in conjunction with the integral field spectrograph, OSIRIS, at the Keck II telescope, we are able to differentiate between the older, late-type (~1Gyr) stars, which are presumed to be dynamically relaxed, and the unrelaxed young (~6Myr) population. This distinction is crucial for testing models of stellar cusp formation in the vicinity of a black hole, as the models assume that the cusp stars are in dynamical equilibrium in the black hole potential. In the survey region, we classified 60 stars as early-type (O and early B; 22 newly identified) and 74 stars as late-type (K and M; 61 newly identified). We find that contamination from young stars is significant, with more than twice as many young stars as old stars in our sensitivity range (K'<15.5) within the central arcsecond.
- ID:
- ivo://CDS.VizieR/J/A+A/540/A85
- Title:
- Spectroscopy of very low mass objects
- Short Name:
- J/A+A/540/A85
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- With a uniform VLT SINFONI data set of nine targets, we have developed an empirical grid of J, H, K spectra of the atmospheres of objects estimated to have very low substellar masses of ~5-20M_Jup_ and young ages ranging from ~1-50Myr. Most of the targets are companions, objects which are especially valuable for comparison with atmosphere and evolutionary models, as they present rare cases in which the age is accurately known from the primary. Based on the youth of the sample, all objects are expected to have low surface gravity, and this study investigates the critical early phases of the evolution of substellar objects. The spectra are compared with grids of five different theoretical atmosphere models. ************************************************************************** * * * Sorry, but the author(s) never supplied the tabular material * * announced in the paper * * * **************************************************************************
- ID:
- ivo://CDS.VizieR/J/A+A/546/L3
- Title:
- Spectrum of LSR J0745+2627
- Short Name:
- J/A+A/546/L3
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We report the identification of LSR J0745+2627 in the United Kingdom InfraRed Telescope Infrared Deep Sky Survey (UKIDSS) Large Area Survey (LAS) as a cool white dwarf with kinematics and age compatible with the thick-disk/halo population. LSR J0745+2627 has a high proper motion (890mas/yr) and a high reduced proper motion value in the J band (H_J=21.87). We show how the infrared-reduced proper motion diagram is useful for selecting a sample of cool white dwarfs with low contamination. LSR J0745+2627 is also detected in the Sloan Digital Sky Survey (SDSS) and the Wide-field Infrared Survey Explorer (WISE). We have spectroscopically confirmed this object as a cool white dwarf using X-Shooter on the Very Large Telescope. An analysis of its spectral energy distribution reveals that its atmosphere is compatible with a pure-H composition model with an effective temperature of 3880+/-90K. This object is the brightest pure-H ultracool white dwarf (Teff<4000K) ever identified. We have constrained the distance (24-45pc), space velocities and age considering different surface gravities. The results obtained suggest that LSR J0745+2627 belongs to the thick-disk/halo population and is also one of the closest ultracool white dwarfs.
