- 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.
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- 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.
- ID:
- ivo://CDS.VizieR/J/AJ/154/62
- Title:
- Orbital parameters of Kuiper Belt objects
- Short Name:
- J/AJ/154/62
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We measured the mean plane of the Kuiper Belt as a function of semimajor axis. For the classical Kuiper Belt as a whole (the nonresonant objects in the semimajor axis range 42-48au), we find a mean plane of inclination i_m_=1.8{deg}_-0.4{deg}_^+0.7{deg}^ and longitude of ascending node {Omega}_m_=77{deg}_-14{deg}_^+18{deg}^ (in the J2000 ecliptic-equinox coordinate system), in accord with theoretical expectations of the secular effects of the known planets. With finer semimajor axis bins, we detect a statistically significant warp in the mean plane near semimajor axes 40-42au. Linear secular theory predicts a warp near this location due to the {nu}_18_ nodal secular resonance; however, the measured mean plane for the 40.3-42au semimajor axis bin (just outside the {nu}_18_) is inclined ~13{deg} to the predicted plane, a nearly 3{sigma} discrepancy. For the more distant Kuiper Belt objects of semimajor axes in the range 50-80au, the expected mean plane is close to the invariable plane of the solar system, but the measured mean plane deviates greatly from this: it has inclination i_m_=9.1{deg}_-3.8{deg}_^+6.6{deg}^ and longitude of ascending node {Omega}_m_=227{deg}_-44{deg}_^+18{deg}^. We estimate this deviation from the expected mean plane to be statistically significant at the ~97%-99% confidence level. We discuss several possible explanations for this deviation, including the possibility that a relatively close-in (a<~100au), unseen, small planetary-mass object in the outer solar system is responsible for the warping.
- ID:
- ivo://CDS.VizieR/J/AJ/116/1998
- Title:
- Outer planetary systems
- Short Name:
- J/AJ/116/1998
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- In order to better understand the range of dynamically long-lived giant planet systems, we present the results of a set of bottom-up numerical simulations designed to generate plausible giant planet systems from a large number of planetary embryos. Our simulations produced systems that are stable for at least a billion years and that exhibit a wide range of characteristics. Some of these systems are reminiscent of the outer solar system. The number of planets ranged from one to seven. Many systems contained only Uranus-mass objects. We constructed systems that were more compact than the outer solar system and systems that were much sparser, with planets on very eccentric orbits. Perhaps most surprisingly, some of the systems that we constructed were stable for at least a billion years despite undergoing macroscopic orbital changes on much shorter timescales.
- ID:
- ivo://CDS.VizieR/J/MNRAS/462/1351
- Title:
- Outer satellites occultation predictions
- Short Name:
- J/MNRAS/462/1351
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Gomes-Junior et al. (2015, Cat. J/A+A/580/A76) published 3613 positions for the 8 largest irregular satellites of Jupiter and 1787 positions for the largest irregular satellite of Saturn, Phoebe. These observations were made between 1995 and 2014 and have an estimated error of about 60 to 80 mas. Based on this set of positions, we derived new orbits for the eight largest irregular satellites of Jupiter: Himalia, Elara, Pasiphae, Carme, Lysithea, Sinope, Ananke and Leda. For Phoebe we updated the ephemeris from Desmars et al. (2013, Cat. J/A+A/553/A36) using 75% more positions than the previous one. Due to their orbital characteristics, it is common belief that the irregular satellites were captured by the giant planets in the early Solar System, but there is no consensus for a single model explaining where they were formed. Size, shape, albedo and composition would help to trace back their true origin, but these physical parameters are yet poorly known for irregular satellites. The observation of stellar occultations would allow for the determination of such parameters. Indeed Jupiter will cross the galactic plane in 2019-2020 and Saturn in 2018, improving a lot the chances of observing such events in the near future. Using the derived ephemerides and the UCAC4 catalogue we managed to identify 5442 candidate stellar occultations between January 2016 and December 2020 for the 9 satellites studied here. We discussed how the successful observation of a stellar occultation by these objects is possible and present some potential occultations.
- ID:
- ivo://CDS.VizieR/J/AJ/152/70
- Title:
- Outer Solar System Origins Survey (OSSOS). I.
- Short Name:
- J/AJ/152/70
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We report the discovery, tracking, and detection circumstances for 85 trans-Neptunian objects (TNOs) from the first 42deg^2^ of the Outer Solar System Origins Survey. This ongoing r-band solar system survey uses the 0.9deg^2^ field of view MegaPrime camera on the 3.6m Canada-France-Hawaii Telescope. Our orbital elements for these TNOs are precise to a fractional semimajor axis uncertainty <0.1%. We achieve this precision in just two oppositions, as compared to the normal three to five oppositions, via a dense observing cadence and innovative astrometric technique. These discoveries are free of ephemeris bias, a first for large trans-Neptunian surveys. We also provide the necessary information to enable models of TNO orbital distributions to be tested against our TNO sample. We confirm the existence of a cold "kernel" of objects within the main cold classical Kuiper Belt and infer the existence of an extension of the "stirred" cold classical Kuiper Belt to at least several au beyond the 2:1 mean motion resonance with Neptune. We find that the population model of Petit et al. remains a plausible representation of the Kuiper Belt. The full survey, to be completed in 2017, will provide an exquisitely characterized sample of important resonant TNO populations, ideal for testing models of giant planet migration during the early history of the solar system.
