- ID:
- ivo://CDS.VizieR/J/AJ/159/133
- Title:
- Orbital elements of TNOs from the Dark Energy Survey
- Short Name:
- J/AJ/159/133
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The outer solar system contains a large number of small bodies (known as trans-Neptunian objects or TNOs) that exhibit diverse types of dynamical behavior. The classification of bodies in this distant region into dynamical classes-subpopulations that experience similar orbital evolution-aids in our understanding of the structure and formation of the solar system. In this work, we propose an updated dynamical classification scheme for the outer solar system. This approach includes the construction of a new (automated) method for identifying mean motion resonances. We apply this algorithm to the current data set of TNOs observed by the Dark Energy Survey (DES) and present a working classification for all of the DES TNOs detected to date. Our classification scheme yields 1 inner centaur, 19 outer centaurs, 21 scattering disk objects, 47 detached TNOs, 48 securely resonant objects, 7 resonant candidates, and 97 classical belt objects. Among the scattering and detached objects, we detect 8 TNOs with semimajor axes greater than 150au.
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Search Results
- ID:
- ivo://CDS.VizieR/J/MNRAS/444/1793
- Title:
- 25 Ori group low-mass stars
- Short Name:
- J/MNRAS/444/1793
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the results of a survey of the low-mass star and brown dwarf population of the 25 Orionis group. Using optical photometry from the CIDA (Centro de Investigaciones de Astronomia Francisco J. Duarte, Merida, Venezuela) Deep Survey of Orion, near-IR photometry from the Visible and Infrared Survey Telescope for Astronomy and low-resolution spectroscopy obtained with Hectospec at the MMT telescope, we selected 1246 photometric candidates to low-mass stars and brown dwarfs with estimated masses within 0.02<~M/M_{sun}_<~0.8 and spectroscopically confirmed a sample of 77 low-mass stars as new members of the cluster with a mean age of ~7Myr. We have obtained a system initial mass function of the group that can be well described by either a Kroupa power-law function with indices {alpha}3=-1.73+/-0.31 and {alpha}2=0.68+/-0.41 in the mass ranges 0.03<=M/M_{sun}_<=0.08 and 0.08<=M/M_{sun}_<=0.5, respectively, or a Scalo lognormal function with coefficients m_c_=0.21^+0.02^_-0.02_ and {sigma}=0.36+/-0.03 in the mass range 0.03<=M/M_{sun}_<=0.8. From the analysis of the spatial distribution of this numerous candidate sample, we have confirmed the east-west elongation of the 25 Orionis group observed in previous works, and rule out a possible southern extension of the group. We find that the spatial distributions of low-mass stars and brown dwarfs in 25 Orionis are statistically indistinguishable. Finally, we found that the fraction of brown dwarfs showing IR excesses is higher than for low-mass stars, supporting the scenario in which the evolution of circumstellar discs around the least massive objects could be more prolonged.
- ID:
- ivo://CDS.VizieR/J/MNRAS/468/931
- Title:
- Orion Nebula Cluster members VRI photometry
- Short Name:
- J/MNRAS/468/931
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Very young stars, like the Orion Nebula Cluster (ONC) members analysed in the present study, exhibit photometric variability with a wide range of amplitudes. Such a prominent variability reflects in the inferred values of stellar colours and luminosities and, in turn, in the inferred stellar ages and masses. In this study, we measure the amplitudes of the photometric variability in V, R and I optical bands of a sample of 346 ONC members. We use these measurements to investigate how this variability affects the inferred masses and ages and whether it alone can account for the age spread among ONC members reported by earlier studies. We make use of colour-magnitude and Hertzprung-Russell (HR) diagrams. We find that members that show periodic and smooth photometric rotational modulation have masses and ages that are unaffected by variability when theoretical isochrones and evolutionary mass tracks are used in either colour-magnitude or HR diagrams. On the other hand, members with periodic but very scattered photometric rotational modulation and non-periodic members have masses and ages that are significantly affected. Moreover, using HR diagrams, we find that the observed I-band photometric variability can take account of only a fraction (~50 per cent) of the inferred age spread, whereas the V-band photometric variability is large enough to mask any age spread.
- ID:
- ivo://CDS.VizieR/J/A+A/508/1313
- Title:
- Orion pre-main sequence RIJH light curves
- Short Name:
- J/A+A/508/1313
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We performed an intensive photometric monitoring of the PMS stars falling in a field of about 10x10 arcminutes in the vicinity of the Orion Nebula Cluster (ONC). Photometric data were collected between November 2006 and January 2007 with the REM telescope in the VRIJHK' bands. The largest number of observations is in the I band (about 2700 images) and in J and H bands (about 500 images in each filter). From the observed rotational modulation, induced by the presence of surface inhomogeneities, we derived the rotation periods for 16 stars and improved previous determinations for the other 13. The analysis of the spectral energy distributions and, for some stars, of high-resolution spectra provided us with the main stellar parameters (luminosity, effective temperature, mass, age, and vsini). We also report the serendipitous detection of two strong flares in two of these objects. In most cases, the light-curve amplitudes decrease progressively from the R to H band as expected for cool starspots, while in a few cases, they can only be modelled by the presence of hot spots, presumably ascribable to magnetospheric accretion. The application of our own spot model to the simultaneous light curves in different bands allowed us to deduce the spot parameters and particularly to disentangle the spot temperature and size effects on the observed light curves.
- ID:
- ivo://CDS.VizieR/J/ApJS/236/18
- Title:
- OSSOS. VII. TNOs complete data release
- Short Name:
- J/ApJS/236/18
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The Outer Solar System Origins Survey (OSSOS), a wide-field imaging program in 2013-2017 with the Canada-France-Hawaii Telescope, surveyed 155deg^2^ of sky to depths of m_r_=24.1-25.2. We present 838 outer solar system discoveries that are entirely free of ephemeris bias. This increases the inventory of trans-Neptunian objects (TNOs) with accurately known orbits by nearly 50%. Each minor planet has 20-60 Gaia/Pan-STARRS-calibrated astrometric measurements made over 2-5 oppositions, which allows accurate classification of their orbits within the trans-Neptunian dynamical populations. The populations orbiting in mean-motion resonance with Neptune are key to understanding Neptune's early migration. Our 313 resonant TNOs, including 132 plutinos, triple the available characterized sample and include new occupancy of distant resonances out to semimajor axis a ~130au. OSSOS doubles the known population of the nonresonant Kuiper Belt, providing 436 TNOs in this region, all with exceptionally high-quality orbits of a uncertainty {sigma}_a_<=0.1%; they show that the belt exists from a>~37au, with a lower perihelion bound of 35au. We confirm the presence of a concentrated low-inclination a~44 au "kernel" population and a dynamically cold population extending beyond the 2:1 resonance. We finely quantify the survey's observational biases. Our survey simulator provides a straightforward way to impose these biases on models of the trans-Neptunian orbit distributions, allowing statistical comparison to the discoveries. The OSSOS TNOs, unprecedented in their orbital precision for the size of the sample, are ideal for testing concepts of the history of giant planet migration in the solar system.
- ID:
- ivo://CDS.VizieR/J/ApJS/244/19
- Title:
- OSSOS. XII. Subaru/HSC obs. of 65 TNOs
- Short Name:
- J/ApJS/244/19
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present variability measurements and partial light curves of trans-Neptunian objects (TNOs) from a two-night pilot study using Hyper Suprime-Cam (HSC) on the Subaru Telescope (Maunakea, Hawaii, USA). Subaru's large aperture (8m) and HSC's large field of view (1.77deg^2^) allow us to obtain measurements of multiple objects with a range of magnitudes in each telescope pointing. We observed 65 objects with m_r_=22.6-25.5mag in just six pointings, allowing 20-24 visits of each pointing over the two nights. Our sample, all discovered in the recent Outer Solar System Origins Survey (OSSOS), spans absolute magnitudes of H_r_=6.2-10.8mag and thus investigates smaller objects than previous light curve projects have typically studied. Our data supports the existence of a correlation between the light curve amplitude and absolute magnitude seen in other works but does not support a correlation between the amplitude and orbital inclination. Our sample includes a number of objects from different dynamical populations within the trans-Neptunian region, but we do not find any relationship between variability and the dynamical class. We were only able to estimate periods for 12 objects in the sample and found that a longer baseline of observations is required for a reliable period analysis. We find that 31 objects (just under half of our sample) have variability of {Delta}_mag_ greater than 0.4mag during all of the observations; in smaller 1.25hr, 1.85hr, and 2.45hr windows, the median {Delta}_mag_ is 0.13, 0.16, and 0.19mag, respectively. The fact that variability on this scale is common for small TNOs has important implications for discovery surveys (such as OSSOS or the Large Synoptic Survey Telescope) and color measurements.
- ID:
- ivo://CDS.VizieR/J/MNRAS/455/2216
- Title:
- Outer bulge O-rich Mira's JHKL photometry
- Short Name:
- J/MNRAS/455/2216
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We report periods and JHKL observations for 643 oxygen-rich Mira variables found in two outer bulge fields at b=-7{deg} and l=+/-8{deg} and combine these with data on 8057 inner bulge Miras from the OGLE, Macho and 2MASS surveys, which are concentrated closer to the Galactic centre. Distance moduli are estimated for all these stars. Evidence is given showing that the bulge structure is a function of age. The longer period Miras (LogP>2.6, age~5Gyr and younger) show clear evidence of a bar structure inclined to the line of sight in both the inner and outer regions. The distribution of the shorter period (metal-rich globular cluster age) Miras, appears spheroidal in the outer bulge. In the inner region these old stars are also distributed differently from the younger ones and possibly suggest a more complex structure. These data suggest a distance to the galactic centre R_0_, of 8.9kpc, with an estimated uncertainty of ~0.4kpc. The possible effect of helium enrichment on our conclusions is discussed.
- ID:
- ivo://CDS.VizieR/J/ApJS/119/141
- Title:
- Oxygen-rich dust shells IR spectral classification
- Short Name:
- J/ApJS/119/141
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- This paper presents infrared spectral classifications for a flux-limited sample of 635 optically identified oxygen-rich variables including supergiants and sources on the asymptotic giant branch (AGB). Several classes of spectra from oxygen-rich dust exist, and these can be arranged in a smoothly varying sequence of spectral shapes known as the silicate dust sequence. Classification based on this sequence reveals several dependencies of the dust emission on the properties of the central star. Nearly all S stars show broad emission features from alumina dust, while most of the supergiants exhibit classic features from amorphous silicate dust. Mira variables with symmetric light curves generally show broad alumina emission, while those with more asymmetric light curves show classic silicate emission. These differences may arise from differences in the photospheric C/O ratio.
- ID:
- ivo://CDS.VizieR/J/A+A/613/A40
- Title:
- PACS photometry of FIR faint stars
- Short Name:
- J/A+A/613/A40
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Our aims are to determine flux densities and their photometric accuracy for a set of seventeen stars that range in flux from intermediately bright (<~2.5Jy) to faint (>~5mJy) in the far-infrared (FIR). We also aim to derive signal-to-noise dependence with flux and time, and compare the results with predictions from the Herschel exposure-time calculation tool. We obtain aperture photometry from Herschel-PACS high-pass-filtered scan maps and chop/nod observations of the faint stars. The issues of detection limits and sky confusion noise are addressed by comparison of the field-of-view at different wavelengths, by multi-aperture photometry, by special processing of the maps to preserve extended emission, and with the help of large-scale absolute sky brightness maps from AKARI. This photometry is compared with flux-density predictions based on photospheric models for these stars. We obtain a robust noise estimate by fitting the flux distribution per map pixel histogram for the area around the stars, scaling it for the applied aperture size and correcting for noise correlation.
- ID:
- ivo://CDS.VizieR/J/MNRAS/431/2006
- Title:
- PAH in extragalactic star-forming complexes
- Short Name:
- J/MNRAS/431/2006
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The abundance of polycyclic aromatic hydrocarbons (PAHs) in low- and high-metallicity galaxies has been widely discussed since the time when detailed infrared data for extragalactic objects were first obtained. On the scales of entire galaxies, a smaller PAH abundance in lower metallicity galaxies is often observed. We study this relationship for star-forming regions in nearby galaxies, for a sample containing more than 200 HII complexes, using spatially resolved observations from the Herschel Space Observatory and Spitzer Space Telescope. We use a model for the dust emission to estimate the physical parameters (PAH abundance, metallicity, ultraviolet radiation field, etc.) of these complexes. The same correlation of PAH abundance with metallicity, as seen for entire galaxies, is apparently preserved at smaller scales, at least when the Kobulnicky and Kewley metallicity calibration is used. We discuss possible reasons for this correlation, noting that traces of less effective PAH formation in low-metallicity asymptotic giant branch stars should be smeared out by radial mixing in galactic discs. Effective destruction by the harder and more intensive ultraviolet field in low-metallicity environments is qualitatively consistent with our data, as the ultraviolet field intensity, derived from the infrared photometry, is indeed smaller in HII complexes with lower metallicity.
