- ID:
- ivo://CDS.VizieR/J/AJ/135/55
- Title:
- NIR spectra of Centaurs and Kuiper Belt objects
- Short Name:
- J/AJ/135/55
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present here an extensive survey of near-infrared (NIR) spectra of Kuiper belt objects (KBOs) and Centaurs taken with the Keck I Telescope. We find that most spectra in our sample are well characterized by a combination of water ice and a featureless continuum. A comparative analysis reveals that the NIR spectral properties have little correlation to the visible colors or albedo, with the exception of the fragment KBOs produced from the giant impact on 2003 E
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- ID:
- ivo://CDS.VizieR/J/A+A/646/A182
- Title:
- Non-gravitational effects in retrograde orbits
- Short Name:
- J/A+A/646/A182
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Dynamical studies of asteroid populations in retrograde orbits, i.e. with orbital inclinations greater than 90 degrees, are interesting because the origin of such orbits is still unexplained. Generally, the retrograde asteroids population includes mostly Centaurs and transneptunian objects (TNOs). A special case is the Near Earth Object (343158) 2009 HC82 from the Apollo group. Another interesting object is the comet 333P/LINEAR, which for several years was considered as the second retrograde object approaching Earth. One more comet in retrograde orbit, 161P Hartley/IRAS appears to be an object of similar type. Thanks to the large amount of observational data for these two comets, we tested various models of cometary non-gravitational forces applied to their dynamics. The goal was to estimate which of non-gravitational perturbations could affect the stability of retrograde bodies. In principle, we study the local stability by measuring the divergence of nearby orbits. We have numerically determined Lyapunov chaotic indicators (LCI) and the associated Lyapunov times (LT). This time, our calculations of these parameters were extended by more advanced models of non-gravitational perturbations (i.e. Yarkovsky drift and in selected cases cometary forces). This allowed estimating the chaos in the Lyapunov sense. We found that the Yarkovsky effect for obliquities of gamma=0{deg} and gamma=180{deg} can change LT substantially. In most cases, for the prograde rotation, we received more stable solutions. Moreover, we confirmed the role of retrograde resonances in this process. Additionally, the studied cometary effects also significantly influence the long-term behaviour of the selected comets. LT can reach values from 100 to over 1000 years. All results indicate that the use of models with non-gravitational effects for retrograde bodies is clearly justified.
- ID:
- ivo://CDS.VizieR/J/ApJ/720/1691
- Title:
- Observations of the distant Kuiper belt
- Short Name:
- J/ApJ/720/1691
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the results of a wide-field survey using the 1.2m Samuel Oschin Telescope at Palomar Observatory. This survey was designed to find the most distant members of the Kuiper Belt and beyond. We searched ~12000deg^2^ down to a mean limiting magnitude of 21.3 in R. A total number of 52 Kuiper Belt objects and Centaurs have been detected, 25 of which were discovered in this survey. Except for the redetection of Sedna, no additional Sedna-like bodies with perihelia greater than 45AU were detected despite sensitivity out to distances of 1000AU. We discuss the implications for a distant Sedna-like population beyond the Kuiper Belt, focusing on the constraints we can place on the embedded stellar cluster environment the early Sun may be have been born in, where the location and distribution of Sedna-like orbits sculpted by multiple stellar encounters is indicative of the birth cluster size. We also report our observed latitude distribution and implications for the size of the plutino population.
- ID:
- ivo://CDS.VizieR/J/other/SoSyR/53.368
- Title:
- Observations of the Galilean moons
- Short Name:
- J/other/SoSyR/53
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Results of observations of the Galilean moons of Jupiter were carried out at the Normal Astrograph of the Pulkovo Observatory in 2018. We obtained 452 positions of the Galilean moons of Jupiter in the Gaia DR1 catalog system (ICRF, J2000.0) and 671 differential coordinates of the satellites relative to each other. The obtained mean errors in the satellites normal positions on the right ascension and declination, which demonstrate the intrinsic convergence of the observational results, are (eps)RA=0.003" and (eps)DE= 0.003", respectively, for the entire observational period. The errors of one difference are (sigm)RA=0.070", and (sigm)DE=0.067",respectively. The equatorial coordinates of the moons were compared to eight motion theories of planets and satellites. On average, the (O.C) residuals in the both coordinates relative to the motion theories are 0.014". The best agreement with observations is achieved by combination of all four motion theories of satellites with the planetary theory EPM2017, which yields average (O-C) residuals of approximately 0.01" for each of them. The new results were compared to those of the 2016-2017 observational season. As in the past, peculiarities in the behavior of the (O-C) residuals for Io and Ganymede have been noticed.
- ID:
- ivo://CDS.VizieR/J/AJ/156/223
- Title:
- Observations of the main-belt comets 238P & 288P
- Short Name:
- J/AJ/156/223
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We report observations of the reactivations of the main-belt comets (MBCs) 238P/Read and 288P/(300163) 2006 VW_139_ that also track the evolution of each object's activity over several months in 2016 and 2017. We additionally identify and analyze archival SDSS data showing 288P to have been active in 2000, meaning that both 238P and 288P have now each been confirmed to be active near perihelion on three separate occasions. From data obtained of 288P from 2012-2015 when it appeared inactive, we find best-fit R-band H, G phase function parameters of H_R_=16.80+/-0.12 mag and G_R_=0.18+/-0.11, corresponding to effective component radii of r_c_=0.80+/-0.04 km, assuming a binary system with equally sized components. Fitting linear functions to ejected dust masses inferred for 238P and 288P soon after their observed reactivations in 2016, we find an initial average net dust production rate of M_d_=0.7+/-0.3 kg/s and a best-fit start date of 2016 March 11 (when the object was at a true anomaly of {nu}=-63{deg}) for 238P, and an initial average net dust production rate of M_d_=5.6+/-0.7 kg/s and a best-fit start date of 2016 August 5 (when the object was at {nu}=-27{deg}) for 288P. Applying similar analyses to archival data, we find similar start points for previous active episodes for both objects, suggesting that minimal mantle growth or ice recession occurred between the active episodes in question. Some changes in dust production rates between active episodes are detected, however. More detailed dust modeling is suggested to further clarify the process of activity evolution in MBCs.
- ID:
- ivo://CDS.VizieR/J/ApJ/793/50
- Title:
- Observed light curve of (3200) Phaethon
- Short Name:
- J/ApJ/793/50
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- (3200) Phaethon exhibits both comet- and asteroid-like properties, suggesting it could be a rare transitional object such as a dormant comet or previously volatile-rich asteroid. This justifies detailed study of (3200) Phaethon's physical properties as a better understanding of asteroid-comet transition objects can provide insight into minor body evolution. We therefore acquired time series photometry of (3200) Phaethon over 15 nights from 1994 to 2013, primarily using the Tektronix 2048x2048 pixel CCD on the University of Hawaii 2.2 m telescope. We utilized light curve inversion to (1) refine (3200) Phaethon's rotational period to P=3.6032+/-0.0008 hr; (2) estimate a rotational pole orientation of {lambda}=+85{deg}+/-13{deg} and {beta}=-20{deg}+/-10{deg}; and (3) derive a shape model. We also used our extensive light curve data set to estimate the slope parameter of (3200) Phaethon's phase curve as G~0.06, consistent with C-type asteroids. We discuss how this highly oblique pole orientation with a negative ecliptic latitude supports previous evidence for (3200) Phaethon's origin in the inner main asteroid belt as well as the potential for deeply buried volatiles fueling impulsive yet rare cometary outbursts.
- ID:
- ivo://CDS.VizieR/J/A+A/627/A118
- Title:
- Optical activity indicators
- Short Name:
- J/A+A/627/A118
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Understanding stellar activity in solar-type stars is crucial for the physics of stellar atmospheres as well as for ongoing exoplanet programmes. We aim to test how well we understand stellar activity using our own star, the Sun, as a test case. We perform a detailed study of the main optical activity indicators (CaII H & K, Balmer lines, NaI D1, D2, and HeI D3 measured for the Sun using the data provided by the HARPS-N solar-telescope feed at the Telescopio Nazionale Galileo. We make use of periodogram analyses to study solar rotation, and we use the pool variance technique to study the temporal evolution of active regions. The correlations between the different activity indicators as well as the correlations between activity indexes and the derived parameters from the cross-correlation technique are analysed. We also study the temporal evolution of these correlations and their possible relationship with indicators of inhomogeneities in the solar photosphere like sunspot number or radio flux values. The value of the solar rotation period is found in all the activity indicators, with the only exception being H{delta}. The derived values vary from 26.29 days (H{gamma} line) to 31.23 days (HeI). From an analysis of sliding periodograms we find that in most of the activity indicators the spectral power is split into several "bands" of periods around 26 and 30 days, that might be explained by the migration of active regions between the equator and a latitude of ~30{deg}, spot evolution or a combination of both effects. In agreement with previous works a typical lifetime of active regions of ~ ten rotation periods is inferred from the pooled variance diagrams. We find that H{alpha}, H{beta}, H{gamma}, H{epsilon}, and HeI show a significant correlation with the S index. Significant correlations between the contrast, bisector span, and the heliocentric radial velocity with the activity indexes are also found. We show that the full width at half maximum, the bisector, and the disc-integrated magnetic field correlate with the radial velocity variations. The correlation of the S index and H{alpha} changes with time, increasing with larger sun spot numbers and solar irradiance. A similar tendency with the S index - radial velocity correlation is also present in the data. Our results are consistent with a scenario in which higher activity favours the correlation between the S index and the H{alpha} activity indicators and between the S index and radial velocity variations.
- ID:
- ivo://CDS.VizieR/J/AJ/160/282
- Title:
- Optical and IR spectroscopy of Europa
- Short Name:
- J/AJ/160/282
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The composition of Europa's trailing hemisphere reflects the combined influences of endogenous geologic resurfacing and exogenous sulfur radiolysis. Using spatially resolved visible-wavelength spectra of Europa obtained with the Hubble Space Telescope, we map multiple spectral features across the trailing hemisphere and compare their geographies with the distributions of large-scale geology, magnetospheric bombardment, and surface color. Based on such comparisons, we interpret some aspects of our spectra as indicative of purely exogenous sulfur radiolysis products and other aspects as indicative of radiolysis products formed from a mixture of endogenous material and magnetospheric sulfur. The spatial distributions of two of the absorptions seen in our spectra-a widespread downturn toward the near-UV and a distinct feature at 530nm-appear consistent with sulfur allotropes previously suggested from ground-based spectrophotometry. However, the geographies of two additional features-an absorption feature at 360nm and the spectral slope at red wavelengths-are more consistent with endogenous material that has been altered by sulfur radiolysis. We suggest irradiated sulfate salts as potential candidates for this material, but we are unable to identify particular species with the available data.
- ID:
- ivo://CDS.VizieR/J/A+A/423/983
- Title:
- Optical constants for meteoritic nano-diamonds
- Short Name:
- J/A+A/423/983
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We have used different spectroscopic techniques to obtain a consistent quantitative absorption spectrum of a sample of meteoritic nano-diamonds in the wavelength range from the vacuum ultraviolet (0.12um) to the far infrared (100um). The nano-diamonds have been isolated by a chemical treatment from the Allende meteorite (Braatz et al. 2000, Meteorit. Planet. Sci., 35, 75). Electron energy loss spectroscopy (EELS) extends the optical measurements to higher energies and allows the derivation of the optical constants (n & k) by Kramers-Kronig analysis.
- 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.
