- ID:
- ivo://CDS.VizieR/J/ApJ/831/20
- Title:
- C/O and Mg/Si for solar neighborhood's stars
- Short Name:
- J/ApJ/831/20
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The carbon-to-oxygen ratio in a protoplanetary disk can have a dramatic influence on the compositions of any terrestrial planets formed. In regions of high C/O, planets form primarily from carbonates, and in regions of low C/O, the ratio of magnesium to silicon determines the types of silicates that dominate the compositions. We present C/O and Mg/Si ratios for 852 F, G, and K dwarfs in the solar neighborhood. We find that the frequency of carbon-rich dwarfs in the solar neighborhood is <0.13% and that 156 known planet hosts in the sample follow a similar distribution as all of the stars as a whole. The cosmic distribution of Mg/Si for these same stars is broader than the C/O distribution and peaks near 1.0, with ~60% of systems having 1<=Mg/Si<2, leading to rocky planet compositions similar to the Earth. This leaves 40% of systems that can have planets that are silicate-rich and that may have very different compositions than our own.
Number of results to display per page
Search Results
- ID:
- ivo://CDS.VizieR/J/A+A/554/A55
- Title:
- C^18^O(1-0) and N_2_H^+^(1-0) in L1495/B213
- Short Name:
- J/A+A/554/A55
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Core condensation is a critical step in the star-formation process, but it is still poorly characterized observationally. We have studied the 10pc-long L1495/B213 complex in Taurus to investigate how dense cores have condensed out of the lower density cloud material. We observed L1495/B213 in C^18^O(1-0), N_2_H^+^(1-0), and SO(J_N_=3_2_-2_1_) with the 14m FCRAO telescope, and complemented the data with dust continuum observations using APEX (870um) and IRAM 30m (1200um).
- ID:
- ivo://CDS.VizieR/J/A+A/489/1271
- Title:
- CO and OH abundances of 23 K-M giants
- Short Name:
- J/A+A/489/1271
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Based on the high resolution infrared spectra observed with the Fourier Transform Spectrometer (FTS) at the 4m telescope of the Kitt Peak National Observatory (KPNO), ro-vibrational lines of ^12^C^16^O, ^13^C^16^O, ^12^C^17^O, and ^16^OH were measured. Some details of the observed spectra including the resolution, S/N ratio, and data of observation are given in table2. The spectroscopic and equivalent width data are given in table3 for 23 red giant stars. The resulting data are used to investigate the nature of the infrared spectra of K-M giant stars. It is found that only the weak lines (log(W/nu)<-4.75) carry the information on the photosphere and hence can be used to extract the nature of the photosphere such as the stellar abundances. The intermediate-strength (-4.75<log(W/nu)<-4.40) as well as the strong (log(W/nu)>-4.4) lines are badly disturbed by the lines of non-photospheric origin. In other words, most lines dominating the infrared spectra, except for the weak lines, are actually hybrid of at least two different kinds of lines originating in the photosphere and in an extra molecular layers outside of photosphere. The nature of the extra layers is not known well, but it may be related to the molecular envelope producing H_2_O lines, not only in late M but also in early M giants as well. Also, the intermediate-strength lines include those with LEP as high as 2eV and hence the extra molecular layer should be quite warm. For the reason outlined above, we determine C, O, and their isotopic abundances using only the weak lines, but we listed the measured data not only of the weak lines but also of the stronger lines as well in table3, with the hope that these data can be of some use to clarify the nature of the warm extra molecular layers.
- ID:
- ivo://CDS.VizieR/J/ApJS/236/49
- Title:
- CO and 850um obs. of Planck Galactic cold clumps
- Short Name:
- J/ApJS/236/49
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- In order to understand the initial conditions and early evolution of star formation in a wide range of Galactic environments, we carried out an investigation of 64 Planck Galactic cold clumps (PGCCs) in the second quadrant of the Milky Way. Using the ^13^CO and C^18^O J=1-0 lines and 850{mu}m continuum observations, we investigated cloud fragmentation and evolution associated with star formation. We extracted 468 clumps and 117 cores from the ^13^CO line and 850{mu}m continuum maps, respectively. We made use of the Bayesian distance calculator and derived the distances of all 64 PGCCs. We found that in general, the mass-size plane follows a relation of m~r^1.67^. At a given scale, the masses of our objects are around 1/10 of that of typical Galactic massive star-forming regions. Analysis of the clump and core masses, virial parameters, densities, and mass-size relation suggests that the PGCCs in our sample have a low core formation efficiency (~3.0%), and most PGCCs are likely low-mass star-forming candidates. Statistical study indicates that the 850{mu}m cores are more turbulent, more optically thick, and denser than the ^13^CO clumps for star formation candidates, suggesting that the 850{mu}m cores are likely more appropriate future star formation candidates than the ^13^CO clumps.
- ID:
- ivo://CDS.VizieR/J/AJ/139/2347
- Title:
- CO And Vr light curves and RV curve
- Short Name:
- J/AJ/139/2347
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Accurate absolute properties have been determined for the eclipsing triple star CO And (F8+F8) based on extensive differential photometry obtained by three robotic observatories and CfA spectroscopy. The eclipsing binary star orbit is circular with a period of 3.655days. The triple nature of this system is revealed by more than a century of timings of minimum light, and by the presence of third light in the photometric orbits.
- ID:
- ivo://CDS.VizieR/J/MNRAS/454/3816
- Title:
- Cobalt emission in nebular phase spectra
- Short Name:
- J/MNRAS/454/3816
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The light curves of Type Ia supernovae (SNe Ia) are powered by the radioactive decay of ^56^Ni to ^56^Co at early times, and the decay of ^56^Co to ^56^Fe from ~60 d after explosion. We examine the evolution of the [CoIII] {lambda}5893 emission complex during the nebular phase for SNe Ia with multiple nebular spectra and show that the line flux follows the square of the mass of ^56^Co as a function of time. This result indicates both efficient local energy deposition from positrons produced in ^56^Co decay and long-term stability of the ionization state of the nebula. We compile SN Ia nebular spectra from the literature and present 21 new late-phase spectra of 7 SNe Ia, including SN 2014J. From these we measure the flux in the [CoIII] {lambda}5893 line and remove its well-behaved time dependence to infer the initial mass of ^56^Ni (M_Ni_) produced in the explosion. We then examine ^56^Ni yields for different SN Ia ejected masses (M_ej_ - calculated using the relation between light-curve width and ejected mass) and find that the ^56^Ni masses of SNe Ia fall into two regimes: for narrow light curves (low stretch s~0.7-0.9), M_Ni_ is clustered near M_Ni_~0.4M_{sun}_ and shows a shallow increase as M_ej_ increases from ~1 to 1.4M_{sun}_; at high stretch, M_ej_ clusters at the Chandrasekhar mass (1.4M_{sun}_) while M_Ni_ spans a broad range from 0.6 to 1.2M_{sun}_. This could constitute evidence for two distinct SN Ia explosion mechanisms.
3927. COBE DIRBE IR photometry
- ID:
- ivo://CDS.VizieR/J/ApJ/500/554
- Title:
- COBE DIRBE IR photometry
- Short Name:
- J/ApJ/500/554
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- A comparison of the COBE Diffuse Infrared Background Experiment (DIRBE) all-sky survey with the locations of known galaxies in the IRAS Catalog of Extragalactic Objects and the Center for Astrophysics Catalog of Galaxies led to the detection of as many as 57 galaxies. In this paper, we present the photometric data for these galaxies and an analysis of the seven galaxies that were detected at {lambda}>100{mu}m. Estimates of the ratio of the mass of the cold dust (CD) component detected at T_d_=20-30K to a very cold dust (VCD) component with T_d_~10-15K suggest that between 2%-100% of the cirrus-like CD mass can also exist in many of these galaxies as VCD. In one galaxy, M33, the DIRBE photometry at 240{mu}m suggests as much as 26 times as much VCD may be present as compared to the cirrus-like component. Further submillimeter measurements of this galaxy are required to verify such a large population of VCD. We also present 10 galaxies that were detected in the sky region not previously surveyed by IRAS and that can be used to construct a flux-limited all-sky catalog of galaxies brighter than 1000Jy with a modest completeness limit of about 65%.
- ID:
- ivo://CDS.VizieR/J/ApJS/154/673
- Title:
- COBE DIRBE Point Source Catalog
- Short Name:
- J/ApJS/154/673
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the COBE DIRBE Point Source Catalog, an all-sky catalog containing infrared photometry in 10 bands from 1.25 microns to 240 microns for 11788 of the brightest near and mid-infrared point sources in the sky. Since DIRBE had excellent temporal coverage (100-1900 independent measurements per object during the 10 month cryogenic mission), the Catalog also contains information about variability at each wavelength, including amplitudes of variation observed during the mission. Since the DIRBE spatial resolution is relatively poor (0.7{deg}), we have carefully investigated the question of confusion, and have flagged sources with infrared-bright companions within the DIRBE beam. In addition, we filtered the DIRBE light curves for data points affected by companions outside of the main DIRBE beam but within the `sky' portion of the scan. At high Galactic latitudes (|b|>5{deg}), the Catalog contains essentially all of the unconfused sources with flux densities greater than 90, 60, 60, 50, 90, and 165 Jy at 1.25, 2.2, 3.5, 4.9, 12, and 25 microns, respectively, corresponding to magnitude limits of approximately 3.1, 2.6, 1.7, 1.3, -1.3, and -3.5. At longer wavelengths and in the Galactic Plane, the completeness is less certain because of the large DIRBE beam and possible contributions from extended emission. The Catalog also contains the names of the sources in other catalogs, their spectral types, variability types, and whether or not the sources are known OH/IR stars. We discuss a few remarkable objects in the Catalog.
- ID:
- ivo://nasa.heasarc/dirbepsc
- Title:
- COBE DIRBE Point Source Catalog
- Short Name:
- DIRBEPSC
- Date:
- 27 Sep 2024
- Publisher:
- NASA/GSFC HEASARC
- Description:
- This table contains the Cosmic Background Explorer (COBE) Diffuse Infrared Background Experiment (DIRBE) Point Source Catalog, an all-sky catalog containing infrared photometry in 10 bands from 1.25 microns to 240 microns for 11,788 of the brightest near and mid-infrared point sources in the sky. Since DIRBE had excellent temporal coverage (100-1900 independent measurements per object during the 10 month cryogenic mission in 1989 to 1990), the catalog also contains information about variability at each wavelength, including amplitudes of variation observed during the mission. Since the DIRBE spatial resolution is relatively poor (0.7 degrees), the authors carefully investigated the question of confusion, and flagged sources with infrared-bright companions within the DIRBE beam. In addition, they filtered the DIRBE light curves for data points affected by companions outside of the main DIRBE beam but within the `sky' portion of the scan. At high Galactic latitudes (|b| > 5 degrees), the catalog contains essentially all of the unconfused sources with flux densities greater than 90, 60, 60, 50, 90, and 165 Jy at 1.25, 2.2, 3.5, 4.9, 12, and 25 microns, respectively, corresponding to magnitude limits of approximately 3.1, 2.6, 1.7, 1.3, -1.3, and -3.5. At longer wavelengths and in the Galactic Plane, the completeness is less certain because of the large DIRBE beam and possible contributions from extended emission. For each source, for comparison, the names of the sources in other catalogs, their spectral types, variability types, IRAS and 2MASS photometry, SIMBAD spectral types and published variability types, and whether or not the sources are known OH/IR stars are also included. Unlike the IRAS and 2MASS Catalogs, the DIRBE Point Source Catalog was not constructed by searching the DIRBE database with a point source template and extracting sources based on S/N and confirmation criteria. The DIRBE Catalog was constructed using a target sample list obtained from other infrared catalogs. Since DIRBE is much less sensitive per scan than IRAS or 2MASS, essentially all of the point sources with high S/N light curves in the DIRBE database are already contained in IRAS, 2MASS, and/or MSX. Thus, for simplicity, the authors used these previous catalogs to select a sample for the DIRBE Point Source Catalog. Their initial sample included a total of 21,335 sources; the final catalog contains 11,788 sources. The initial sample was selected from the IRAS Point Source Catalog (1988), the 2MASS Point Source Catalog (Cutri 2003), and/or the MSX Point Source Catalog Version 1.2 (Egan et al. 1999, A&A, 349, 236) that satisfied at least one of the following criteria: (a) 2MASS J magnitude <= 4.51 (F<sub>1.25</sub> >= 25 Jy), (b) 2MASS K magnitude <= 3.81 (F<sub>2.2</sub> >= 20 Jy), (c) IRAS or MSX F<sub>12</sub> >= 15 Jy, or (d) IRAS or MSX F<sub>25</sub> >= 27.5 Jy. The 1.25 and 2.2 micron limits are equal to the average 1-sigma sensitivity per scan in the raw DIRBE light curves of Smith et al. (2002, AJ, 123, 948), while the 12 and 25 micron limits are 0.5 times the average noise levels per scan in that study. These low limits were selected in order to avoid missing variable stars that may have been faint during the 2MASS, IRAS, or MSX mission and to improve the completeness at 3.5 and 4.9 micron. Since the filtering process improves the average per measurement uncertainty, a sensitive selection criterion is warranted to include as many sources as possible. There were 7872 sources with 2MASS J <= 4.51, 20,492 sources with 2MASS K <= 3.81, 4969 sources with IRAS F12 >= 15 Jy, 40 sources in the MSX IRAS Gaps survey with MSX F12 >= 15 Jy, 2753 sources with IRAS F25 >= 27.5 Jy, and 18 sources in the MSX IRAS Gaps survey with MSX F25 >= 27.5 Jy. Thus, the initial list is dominated by stars selected by the 2MASS criteria. These lists were merged together to make a single target list, containing 21,335 sources. To merge the 2MASS and IRAS/MSX lists, the authors used a 60 arcsecond matching radius. If more than one 2MASS source was within 60 arcseconds of the IRAS position, they assumed that the brightest K band source was the match. Note that the authors did not include sources in their input list based on their 60 and/or 100 micron IRAS flux densities, as extended emission from cirrus becomes more significant at these wavelengths. This means that the DIRBE Point Source Catalog is biased against very cold objects, such as galaxies and molecular clouds. Since the authors only used the point source catalogs of 2MASS, IRAS, and MSX for source selection, their sample is also biased against extended objects. Note also that they are only targeting sources bright enough to detect their possible variability in the DIRBE database (i.e., sources that may be detected in a single DIRBE scan at at least one DIRBE wavelength). By co-adding the full light curves, it may be possible to detect fainter objects in the DIRBE database, but without variability information and with a higher likelihood of confusion. The COBE DIRBE Point Source Catalog as presented here contains the time-averaged DIRBE flux densities F<sub>nu</sub> in the 10 DIRBE bands for all 11,785 sources in the initial list that had a flux at minimum in the weekly averaged light curve in any of the six shortest DIRBE wavelengths greater than 3 times the average noise per data point, plus three additional sources (see Section 6 of the reference paper). These flux densities were calculated after filtering the light curves. The name of the object in the catalog from which it was originally selected from is also given (IRAS/MSX and/or 2MASS). This table was created by the HEASARC in April 2012 based on <a href="https://cdsarc.cds.unistra.fr/ftp/cats/J/ApJS/154/673">CDS Catalog J/ApJS/154/673</a> files table1.dat, table4.dat and table8.dat, and contains the DIRBE data for 11,788 of the brightest near- and mid-infrared point sources in the sky together with supporting data from 2MASS, IRAS, MSX and other catalogs. This is a service provided by NASA HEASARC .
- ID:
- ivo://CDS.VizieR/J/PASJ/53/971
- Title:
- CO catalog of LMC molecular clouds
- Short Name:
- J/PASJ/53/971
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- From a ^12^CO (J=1-0) survey with the NANTEN telescope, we present a complete catalog of giant molecular clouds (GMCs) in the Large Magellanic Cloud. In total, 107 CO clouds have been identified, 55 of which were detected at more than 3 observed positions. For the 55 clouds, the physical properties, such as size, line-width, virial mass, and CO luminosity, are cataloged.