Long-period comet impact risk mitigation with Earth-based laser arrays

We present an analysis of the dynamic dust coma of&#160;Centaur&#160;29P/Schewassmann-Wachmann 1 and long-period comet C/2020 R4 (Atlas). Comet P/SW1 has&#160;exhibited a considerable level of activity (so-called outbursts) since its discovery in 1925. In 2011, we found the morphology of comet P/SW 1 showed&#160;dust&#160;features in the form of&#160;jets, spirals and shells.&#160;This year, we have obtained multi-wavelength observations of&#160;29P/SW 1's dust coma&#160;at Lulin observatory and we will present preliminary results including the morphological&#160;analysis and&#160;the colour (B-V, V-R, and R-I) investigation of the dust coma when comet is at quiet and active period. At least three outbursts found within two weeks from comet Atlas is unusual for long-period comet. However, we didn&#8217;t find any new jet features and fragments from the morphology of comet Atlas. Except for the color investigation during the outburst, we will also give the dust/gas production rates in the comparison between pre- and post-outbursts.

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Chapter 7.3 Mount Melbourne and Mount Rittmann

Geological Society London Memoirs ◽

10.1144/m55-2018-43 ◽

2021 ◽

pp. M55-2018-43 ◽

Cited By ~ 4

Author(s):

Salvatore Gambino ◽

Pietro Armienti ◽

Andrea Cannata ◽

Paola Del Carlo ◽

Gaetano Giudice ◽

...

Keyword(s):

Risk Mitigation ◽

Research Programme ◽

Monitoring Systems ◽

Time Data ◽

Long Period ◽

Victoria Land ◽

Geophysical Investigations ◽

Antarctic Research ◽

Set Up ◽

The 1960S

AbstractMount Melbourne and Mount Rittmann are quiescent, although potentially explosive, alkaline volcanoes located 100 km apart in Northern Victoria Land quite close to three stations (Mario Zucchelli Station, Gondwana and Jang Bogo). The earliest investigations on Mount Melbourne started at the end of the 1960s; Mount Rittmann was discovered during the 1988–89 Italian campaign and knowledge of it is more limited due to the extensive ice cover. The first geophysical observations at Mount Melbourne were set up in 1988 by the Italian National Antarctic Research Programme (PNRA), which has recently funded new volcanological, geochemical and geophysical investigations on both volcanoes. Mount Melbourne and Mount Rittmann are active, and are characterized by fumaroles that are fed by volcanic fluid; their seismicity shows typical volcano signals, such as long-period events and tremor. Slow deformative phases have been recognized in the Mount Melbourne summit area. Future implementation of monitoring systems would help to improve our knowledge and enable near-real-time data to be acquired in order to track the evolution of these volcanoes. This would prove extremely useful in volcanic risk mitigation, considering that both Mount Melbourne and Mount Rittmann are potentially capable of producing major explosive activity with a possible risk to large and distant communities.

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Do comet groups exist?

International Astronomical Union Colloquium ◽

10.1017/s0252921100084037 ◽

1985 ◽

Vol 83 ◽

pp. 353-363

Author(s):

B.A. Lindblad

Keyword(s):

Computer Program ◽

Confidence Level ◽

Computer Search ◽

Orbital Elements ◽

Similarity Parameter ◽

The Real ◽

Meteor Streams ◽

Long Period ◽

Random Samples ◽

Period Comet

AbstractThe phenomena of comet groups, i.e. sets of comets that exhibit similarity in their orbital elements, is investigated. A computer program based on the D-criterion of orbital similarity is used to search for comet pairs and groups. The reality of the groups is tested by making computer searches in random samples of comet orbits.The data base for the study is 599 long-period comet orbits. The degree of orbital similarity within a comet group was first assumed to be identical to that encountered in meteor streams. The computer search at this level produced five comet pairs plus two groups with four and seven members, respectively. The latter two represented the eleven known members of the Kreutz group of sun-grazing comets. A comparison with searches in random samples showed that the two Kreutz groups were significant. There is a probability of 0.2 that the five comet pairs found in the real sample could be accidental formations.In a second study the orbital similarity parameter Ds was varied and the number of comet groups found in the real and synthetic comet populations was compared at each level of Ds. Apart from the Kreutz group of comets, the number of groups detected in the real comet sample was for all levels of orbital similarity only slightly higher than the average found in the random samples. At the 2σ confidence level we conclude that comet groups exhibit similarity in their orbital elements, that is no greater than might be expected by chance.

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A surprise in the updated list of stellar perturbers of long-period comet motion

Astronomy and Astrophysics ◽

10.1051/0004-6361/202037876 ◽

2020 ◽

Vol 640 ◽

pp. A129 ◽

Cited By ~ 1

Author(s):

Rita Wysoczańska ◽

Piotr A. Dybczyński ◽

Magdalena Polińska

Keyword(s):

High Mass ◽

Stellar Systems ◽

Mass Estimation ◽

Long Period ◽

The Past ◽

Galactic Potential ◽

History Of ◽

Database Interface ◽

The Masses ◽

Period Comet

Context. The second Gaia data release (Gaia DR2) provided us with the precise five-parameter astrometry for 1.3 billion of sources. As stars passing close to the Solar System are thought to influence the dynamical history of long-period comets, we update and extend the list of stars that could potentially perturb the motion of these comets. Aims. We announce a publicly available database containing an up-to-date list of stars and stellar systems potentially perturbing the motion of long-period comets. We add new objects and revise previously published lists. Special emphasis is placed on stellar systems. A discussion of mass estimation is included. Methods. Using the astrometry, preferably from Gaia DR2, augmented with data from other sources, we calculate nominal spatial positions and velocities for each star. To filter studied objects on the basis of their nominal minimum heliocentric distances we numerically integrate the motion of stars under the Galactic potential and their mutual interactions. Results. We announce the updated list of stellar perturbers of cometary motion, including the masses of perturbers along with the publicly available database interface. These data are ready to be used with the observed long-period comets orbits to study an individual influence of a whole sample of perturbers, or specific stars, on a dynamical past or future of a specific comet. New potential perturbers were added; there are 138 more than in the previously published sources. Conclusions. We demonstrate that a new set of prospective perturbers is an important tool in studies of cometary dynamics. The use of our data changes the results of the past and future cometary motion analysis. We point out a puzzling object in our list, star ALS 9243. The Gaia DR2 astrometry suggests a very close encounter of this star with the Sun; however, its astrophysical parameters result in a completely different current distance of ALS 9243 and its high mass.

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Sublimation-driven evolution of the local radius and the moment of inertia of a long-period comet

Acta Geophysica ◽

10.2478/s11600-009-0005-x ◽

2009 ◽

Vol 57 (2) ◽

pp. 509-535 ◽

Cited By ~ 1

Author(s):

Beata Dziak-Jankowska ◽

Jacek Leliwa-Kopystyński ◽

Konrad J. Kossacki

Keyword(s):

Moment Of Inertia ◽

Long Period ◽

The Moment ◽

Period Comet

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On the actual existence of the periodic and long-period comet families of Uranus

Kinematics and Physics of Celestial Bodies ◽

10.3103/s0884591313020037 ◽

2013 ◽

Vol 29 (2) ◽

pp. 86-92

Author(s):

A. S. Guliev ◽

R. A. Guliev

Keyword(s):

Long Period ◽

Actual Existence ◽

Period Comet

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Cometary Activity Begins at Kuiper Belt Distances: Evidence from C/2017 K2

10.5194/epsc2021-327 ◽

2021 ◽

Author(s):

David Jewitt ◽

Yoonyoung Kim ◽

Max Mutchler ◽

Jessica Agarwal ◽

Jing Li ◽

...

Keyword(s):

Mass Loss ◽

Heliocentric Distance ◽

Kuiper Belt ◽

Near Surface ◽

Water Ice ◽

Distance Range ◽

Long Period ◽

Effective Particle ◽

Lag Effect ◽

Period Comet

We discuss the development of activity in the extraordinary, distant long-period comet C/2017 K2 over the heliocentric distance range&#160;9 < rH < 16 AU.&#160; C/2017 K2 is an incoming long-period comet with a period so long (~ 3 Myr) that no heat from the previous perihelion can be retained; we can be sure that the observed mass-loss is driven by the current insolation and not by a thermal lag.&#160; The comet is characterized by a steady-state coma of sub-millimeter and larger particles ejected at low (4 m/s) velocity, filling a roughly spheroidal coma with a characteristic scale of 80,000 km.&#160; In a fixed, co-moving volume around the nucleus we find that the scattering cross-section of the coma, C, is related to the heliocentric distance by a power law, C ~ rH-s, with heliocentric index s = 1.14+/-0.05. This dependence is significantly weaker than the rH-2, variation of the&#160;insolation as a result of two effects.&#160; These are, first, the heliocentric dependence of the dust velocity and, second, a lag effect due to very slow-moving&#160;particles ejected long before the observations were taken. &#160; A Monte Carlo&#160;model of the photometry shows that dust production beginning at rH ~ 35 AU is needed to match the measured heliocentric index, with only a slight dependence on the particle size distribution.&#160; Dust mass loss rates at 10 AU are of order dM/dt ~ 103 a1 kg/s, where 0.1 < a1 < 1 is the effective particle radius expressed in millimeters. The expulsion of submillimeter and larger grains, beginning at Kuiper belt distances, is likely the result of the sublimation of near-surface supervolatile ice (probably CO, as suggested by the recent detection of this molecule at 6.7 AU; Yang et al. Ap. J. Letters, in press). Water ice is involatile over the observed distance range and even the energy and gas release triggered by the crystallization of amorphous ice, if present, cannot produce activity at 35 AU.&#160; Comet C/2017 K2 will reach perihelion near Mars' orbit in December 2022.&#160;&#160; &#160; This work is described in D. Jewitt, Y. Kim. M. Mutchler, J. Agarwal, J. Li and H. Weaver (2021).&#160; Astronomical Journal, 161:188 (11pp)&#160;

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Disintegration of Long-period Comet C/2019 Y4 (ATLAS). I. Hubble Space Telescope Observations

The Astronomical Journal ◽

10.3847/1538-3881/abfec3 ◽

2021 ◽

Vol 162 (2) ◽

pp. 70

Author(s):

Quanzhi Ye ◽

David Jewitt ◽

Man-To Hui ◽

Qicheng Zhang ◽

Jessica Agarwal ◽

...

Keyword(s):

Hubble Space Telescope ◽

Space Telescope ◽

Long Period ◽

Period Comet

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Long-period comet C/1963 A1 (Ikeya), the probable parent body of π-Hydrids, δ-Corvids, November α-Sextantids, and ϑ-Leonids

Astronomy and Astrophysics ◽

10.1051/0004-6361/201936407 ◽

2019 ◽

Vol 631 ◽

pp. A112 ◽

Cited By ~ 1

Author(s):

L. Neslušan ◽

M. Hajduková

Keyword(s):

Dynamical Evolution ◽

Parent Body ◽

Video Data ◽

Surveillance Video ◽

Evolutionary Time ◽

Meteoroid Stream ◽

Long Period ◽

The Mean ◽

Meteor Data ◽

Period Comet

Aims. We study the meteoroid stream of the long-period comet C/1963 A1 (Ikeya) to predict the meteor showers originating in this comet. We also aim to identify the predicted showers with their real counterparts. Methods. We modeled 23 parts of a theoretical meteoroid stream of the parent comet considered. Each of our models is characterized by a single value of the evolutionary time and a single value of the strength of the Poynting–Robertson effect. The evolutionary time is defined as the time before the present when the stream is modeled and when we start to follow its dynamical evolution. This period ranges from 10 000 to 80 000 yr. In each model, we considered a stream consisting of 10 000 test particles that dynamically evolve, and their dynamics is followed via a numerical integration up to the present. At the end of the integration, we analyzed the mean orbital characteristics of particles in the orbits approaching Earth’s orbit, which thus enabled us to predict a shower related to the parent comet. We attempted to identify each predicted shower with a shower recorded in the International Astronomical Union Meteor Data Center list of all showers. In addition, we tried to separate, often successfully, a real counterpart of each predicted shower from the databases of real meteors. Results. Many modeled parts of the stream of comet C/1963 A1 are identified with the corresponding real showers in three video-meteor databases. No real counterpart is found in the IAU MDC photographic or radio-meteor data. Specifically, we predict five showers related to C/1963 A1. Two predicted showers are identified with π-Hydrids #101 and δ-Corvids #729. The third predicted shower is only vaguely similar to November α-Sextantids #483, when its mean orbit is compared with the mean orbit of the November α-Sextantids in the IAU MDC list of all showers. However, the prediction is very consistent with the corresponding showers newly separated from three video databases. Another predicted shower has no counterpart in the IAU MDC list, but there is a good match of the prediction and a shower that we separated from the Cameras for Allsky Meteor Surveillance video data. We name this new shower ϑ-Leonids. The last of the predicted showers should be relatively low in number and, hence, no real counterparts were either found in the IAU MDC list or separated from any considered database.

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