- ID:
- ivo://CDS.VizieR/J/AJ/157/186
- Title:
- r'-band photometry of comet 96P/Machholz 1
- Short Name:
- J/AJ/157/186
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We observed comet 96P/Machholz 1 on a total of nine nights before and after perihelion during its 2017/2018 apparition. Both its unusually small perihelion distance and the observed fragmentation during multiple apparitions make 96P an object of great interest. Our observations show no evidence of a detectable dust coma, implying that we are observing a bare nucleus at distances ranging from 2.3 to 3.8 au. Based on this assumption, we calculated its color and found average values of g'-r'=0.50+/-0.04, r'-i'=0.17+/-0.03, and i'-z'=0.06+/-0.04. These are notably more blue than those of the nuclei of other Jupiter-family and long-period comets. Furthermore, assuming a bare nucleus, we found an equivalent nuclear radius of 3.4+/-0.2 km with an axial ratio of at least 1.6+/-0.1. The lightcurve clearly displays one large peak, one broad flat peak, and two distinct troughs, with a clear asymmetry that suggests that the shape of the nucleus deviates from that of a simple triaxial ellipsoid. This asymmetry in the lightcurve allowed us to constrain the nuclear rotation period to 4.10+/-0.03 hr and 4.096+/-0.002 hr before and after perihelion, respectively. Within the uncertainties, 96P's rotation period does not appear to have changed throughout the apparition, and we conclude a maximum possible change in rotation period of 130 s. The observed properties were compared to those of comet 322P and interstellar object 1I/'Oumuamua in an attempt to study the effects of close perihelion passages on cometary surfaces and their internal structure and the potential interstellar origin of 96P.
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Search Results
- ID:
- ivo://CDS.VizieR/J/MNRAS/462/S138
- Title:
- Robotic view of 67P perihelion
- Short Name:
- J/MNRAS/462/S138
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Around the time of its perihelion passage, the observability of 67P/Churyumov-Gerasimenko from Earth was limited to very short windows each morning from any given site, due to the low solar elongation of the comet. The peak in the comet's activity was therefore difficult to observe with conventionally scheduled telescopes, but was possible where service/queue-scheduled mode was possible, and with robotic telescopes. We describe the robotic observations that allowed us to measure the total activity of the comet around perihelion, via photometry (dust) and spectroscopy (gas), and compare these results with the measurements at this time by Rosetta's instruments. The peak of activity occurred approximately two weeks after perihelion. The total brightness (dust) largely followed the predictions from Snodgrass et al., with no significant change in total activity levels from previous apparitions. The CN gas production rate matched previous orbits near perihelion, but appeared to be relatively low later in the year.
- ID:
- ivo://CDS.VizieR/J/A+A/652/A59
- Title:
- SDSS Solar System Objects
- Short Name:
- J/A+A/652/A59
- Date:
- 22 Feb 2022
- Publisher:
- CDS
- Description:
- The populations of small bodies of the Solar System (asteroids, comets, Kuiper-Belt objects) are used to constrain the origin and evolution of the Solar System. Both their orbital distribution and composition distribution are required to track the dynamical pathway from their regions of formation to their current locations. We aim at increasing the sample of Solar System objects that have multi-filter photometry and compositional taxonomy. We search for moving objects in the archive of the Sloan Digital Sky Survey. We attempt at maximizing the number of detections by using loose constraints on the extraction. We then apply a suite of filters to remove false-positive detections (stars or galaxies) and mark out spurious photometry and astrometry. We release a catalog of 1542522 entries, consisting of 1036322 observations of 379714 known and unique SSOs together with 506200 observations of moving sources not linked with any known SSOs. The catalog completeness is estimated to be about 95% and the purity to be above 95% for known SSOs.
- ID:
- ivo://CDS.VizieR/J/A+A/598/A40
- Title:
- Separation and confirmation of showers
- Short Name:
- J/A+A/598/A40
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Using IAU MDC photographic, IAU MDC CAMS video, SonotaCo video, and EDMOND video databases, we aim to separate all provable annual meteor showers from each of these databases. We intend to reveal the problems inherent in this procedure and answer the question whether the databases are complete and the methods of separation used are reliable. We aim to evaluate the statistical significance of each separated shower. In this respect, we intend to give a list of reliably separated showers rather than a list of the maximum possible number of showers.
- ID:
- ivo://CDS.VizieR/J/A+A/651/A25
- Title:
- 4 short-period comets spectra
- Short Name:
- J/A+A/651/A25
- Date:
- 22 Feb 2022
- Publisher:
- CDS
- Description:
- We present the results of millimetre-wave spectroscopic observations and spectral surveys of the following short-period comets: 21P/Giacobini-Zinner in September 2018, 41P/Tuttle-Giacobini-Kresak in April 2017, 64P/Swift-Gehrels and 38P/Stephan-Oterma in December 2018, carried out with the IRAM 30-m radio telescope at wavelengths between 1 and 3~mm. Comet 21P was also observed in November 1998 with the IRAM 30-m, JCMT and CSO radio telescopes at wavelengths from 0.8 to 3~mm. The abundances of the following molecules have been determined in those comets: HCN, CH_3_OH, CS, H_2_CO, CH_3_CN and H_2_S in comet 21P, HCN and CH_3_OH in 41P, HCN, CH_3_OH and CS in 64P, and CH_3_OH in 38P. The three last comets, classified as carbon-chain typical from visible spectro-photometry, are relatively rich in methanol (3.5 to 5% relative to water). On the other hand, comet 21P, classified as carbon-chain depleted, shows abundances relative to water which are low for methanol (1.7%), very low for H2S (0.1%) and also relatively low for H2CO (0.16%) and CO (<2.5%). Observations of comet 21P do not show any change in activity and composition between the 1998 and 2018 perihelions. Sensitive upper limits on the abundances of other molecules such as CO, HNCO, HNC or SO are also reported for these comets.
- ID:
- ivo://CDS.VizieR/J/A+A/575/A52
- Title:
- Short-term variability of comet C/2012S1
- Short Name:
- J/A+A/575/A52
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We observed comet C/2012 S1 (ISON) during six nights in February 2013 when it was at 4.8AU from the Sun. At this distance and time the comet was not very active and it was theoretically possible to detect photometric variations likely due to the rotation of the cometary nucleus. The goal of this work is to obtain differential photometry of the comet inner coma using different aperture radii in order to derive a possible rotational period.
- ID:
- ivo://CDS.VizieR/J/ApJ/703/121
- Title:
- Spectroscopy of comet C/2004 Q2 (Machholz)
- Short Name:
- J/ApJ/703/121
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We observed comet C/2004 Q2 (Machholz) with the Keck II telescope in late 2005 January and we obtained the spectra of C/2004 Q2 including many emission lines of volatile species such as H_2_O, HCN, C_2_H_2_, NH_3_, CH_4_, C_2_H_6_, CH_3_OH, and H_2_CO with high-signal-to-noise ratios. Based on our observations, we determined the mixing ratios of the molecules relative to H_2_O in C/2004 Q2. C/2004 Q2 might be the intermediate type between Oort Cloud and Jupiter Family comets. To investigate the formation conditions of such intermediate type comet, we focused on the (C_2_H_2_+C_2_H_6_)/H_2_O ratios and C_2_H_6_/(C_2_H_6_+C_2_H_2_) ratios in comets from the viewpoint of conversion from C_2_H_2_ to C_2_H_6_ in the precometary ices. We employed the dynamical-evolutional model and the chemical-evolutional model to determine the formation region of C/2004 Q2 more precisely. We found that comet C/2004 Q2 might have formed in relatively inner region of the solar nebula than the typical Oort Cloud comet (but slightly further than 5AU from the proto-Sun).
- ID:
- ivo://CDS.VizieR/J/MNRAS/454/3267
- Title:
- Stellar encounters with long-period comets
- Short Name:
- J/MNRAS/454/3267
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The Solar system's Oort cloud can be perturbed by the Galactic tide and by individual passing stars. These perturbations can inject Oort cloud objects into the inner parts of the Solar system, where they may be observed as the long-period comets (periods longer than 200yr). Using dynamical simulations of the Oort cloud under the perturbing effects of the tide and 61 known stellar encounters, we investigate the link between long-period comets and encounters. We find that past encounters were responsible for injecting at least 5 percent of the currently known long-period comets. This is a lower limit due to the incompleteness of known encounters. Although the Galactic tide seems to play the dominant role in producing the observed long-period comets, the non-uniform longitude distribution of the cometary perihelia suggests the existence of strong - but as yet unidentified - stellar encounters or other impulses. The strongest individual future and past encounters are probably HIP 89825 (Gliese 710) and HIP 14473, which contribute at most 8 and 6 percent to the total flux of long-period comets, respectively. Our results show that the strength of an encounter can be approximated well by a simple proxy, which will be convenient for quickly identifying significant encounters in large data sets. Our analysis also indicates a smaller population of the Oort cloud than is usually assumed, which would bring the mass of the solar nebula into line with planet formation theories.
- ID:
- ivo://CDS.VizieR/J/A+A/625/L13
- Title:
- TESS light curve of beta Pictoris
- Short Name:
- J/A+A/625/L13
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We search for signs of falling evaporating bodies (FEBs, also known as exocomets) in photometric time series obtained for {beta} Pictoris after fitting and removing its {delta} Scuti-type pulsation frequencies. Using photometric data obtained by the TESS satellite we determined the pulsational properties of the exoplanet host star {beta} Pictoris through frequency analysis. We then pre-whitened the 54 identified {delta} Scuti p-modes and investigated the residual photometric time series for the presence of FEBs. We identify three distinct dipping events in the light curve of {beta} Pictoris over a 105-day period. These dips have depths from 0.5 to 2-millimagnitudes and durations of up to 2-days for the largest dip. These dips are asymmetric in nature and are consistent with a model of an evaporating comet with an extended tail crossing the disc of the star. We present the first broadband detections of exocomets crossing the disc of {beta} Pictoris, complementing the predictions made 20 years earlier by Lecavelier Des Etangs et al. (1999A&A...343..916L). No periodic transits are seen in this time series. These observations confirm the spectroscopic detection of exocomets in calcium H and K lines that have been seen in high resolution spectroscopy.
- ID:
- ivo://CDS.VizieR/J/A+A/444/287
- Title:
- The nuclei of 3 comets
- Short Name:
- J/A+A/444/287
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Jupiter Family comets (JFCs) are short period comets which have recently entered the inner solar system, having previously orbited in the Kuiper Belt since the formation of the planets. We used two nights on the 3.6 m New Technology Telescope (NTT) at the European Southern Observatory, to obtain VRI photometry of three JFCs; 7P/Pons-Winnecke, 14P/Wolf and 92P/Sanguin. These were observed to be stellar in appearance.
