On the similarity of dust flows in the inner coma of comets

Захаров, Владимир; Rotundi, A.; Corte, Vincenzo Della; Fulle, M.; Ivanovski, S.; Родионов, А. В.; Bykov, N. Y.

doi:10.1016/j.icarus.2021.114476

Cited by 10 publications

(10 citation statements)

References 16 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…On the other side, if we are interested in an assessment of order of magnitude, it is possible to scale the available numerical data to other sizes instead of time consuming numerical simulations. For the scaling we use the relation from Ivanovski et al (2021) which is based on the approach proposed in Zakharov et al (2018) and further developed in Zakharov et al (2021). This approach uses a set of universal, dimensionless parameters, which characterize the dust motion in the inner cometary coma and allows one to reveal dust flows similarities.…”

Section: Results Of the Dynamical Modelingmentioning

confidence: 99%

“…The gas is assumed to behave as an ideal gas expanding into vacuum, so that it has initial sonic velocity given by Vs = γTskB/mg where γ is the ratio of specific heats, mg is the mass of a water molecule, and kB is the Boltzmann constant. The gas density (ρg), velocity (Vg), and temperature (Tg) are computed as a function of the distance to the nucleus, r, by using the analytical expressions given by Zakharov et al (2018), appropriate for an adiabatic spherical expansion.…”

Section: Aerodynamic Force and Torquementioning

confidence: 99%

See 1 more Smart Citation

Dynamics of irregularly-shaped cometary particles subjected to outflowing gas and solar radiative forces and torques

Moreno,

Guirado,

Muñoz

et al. 2021

Preprint

View full text Add to dashboard Cite

The dynamics of irregularly-shaped particles subjected to the combined effect of gas drag and radiative forces and torques in a cometary environment is investigated. The equations of motion are integrated over distances from the nucleus surface up to distances where the gas drag is negligible. The aerodynamic forces and torques are computed assuming a spherically symmetric expanding gas. The calculations are limited to particle sizes in the geometric optics limit, which is the range of validity of our radiative torque calculations. The dynamical behaviour of irregular particles is quite different to those exhibited by non-spherical but symmetric particles such as spheroids. An application of the dynamical model to comet 67P/Churyumov-Gerasimenko, the target of the Rosetta mission, is made. We found that, for particle sizes larger than ∼10 µm, the radiative torques are negligible in comparison with the gas-driven torques up to a distance of ∼100 km from the nucleus surface. The rotation frequencies of the particles depend on their size, shape, and the heliocentric distance, while the terminal velocities, being also dependent on size and heliocentric distance, show only a very weak dependence on particle shape. The ratio of the sum of the particles projected areas in the sun-to-comet direction to that of the sum of the particles projected areas in any direction perpendicular to it is nearly unity, indicating that the interpretation of the observed u-shaped scattering phase function by Rosetta/OSIRIS on comet 67P coma cannot be linked to mechanical alignment of the particles.

show abstract

Section: Results Of the Dynamical Modelingmentioning

confidence: 99%

Section: Aerodynamic Force and Torquementioning

confidence: 99%

Dynamics of irregularly-shaped cometary particles subjected to outflowing gas and solar radiative forces and torques

Moreno,

Guirado,

Muñoz

et al. 2021

Preprint

View full text Add to dashboard Cite

show abstract

“…The gas results are used to calculate the dynamics of spherical dust particles taking into account gas drag, nucleus gravity, and solar radiation pressure (Eq. 1; Zakharov et al, 2018bZakharov et al, , 2021b). An important implicit assumptions to reiterate is that we assume that the dust does not have a back reaction effect on the gas flow.…”

Section: The Dust Particle Dynamicsmentioning

confidence: 99%

Determining the dust environment of an unknown comet for a spacecraft flyby: The case of ESA’s Comet Interceptor mission

Marschall

Захаров

Tubiana

et al. 2022

A&A

View full text Add to dashboard Cite

Context: Assessment of the dust environment of a comet is needed for data analysis and planning of spacecraft missions, such as ESA's Comet Interceptor (CI) mission. The distinctive feature of CI is that the target object will be defined shortly before (or even after) launch therefore the properties of the nucleus and dust environment are poorly constrained and therefore make the assessment of the dust environment challenging. Aims:The main goal of the work is to provide realistic estimations of a dust environment based on very general parameters of possible target objects.

show abstract

“…v g : Maximum terminal gas velocity (m s −1 ). v d : Maximum terminal dust velocity (m s −1 ) at the reference value β 0 assuming no gravity by a nucleus of radius R n = 1 km (Zakharov et al 2018(Zakharov et al , 2021.…”

Section: Ac T I V I T Y M O D E L B E Yo N D 4 Aumentioning

confidence: 99%

“…where C q = 20 kg m −2 (Cremonese et al 2020 ), and thus depends on r 1 −k h . The dust velocities scale as √ R n , where R n is the nucleus radius [equation ( 29) in Zakharov et al ( 2021 ), where the gas loss rate is proportional to R 2 n Q ]. It follows that the three free parameters of the probabilistic model of tails observed at 4 < r h < 10 au are all correlated to R n : the larger R n , the larger v d (proportional to √ R n ), the larger k (i.e.…”

Section: Ac T I V I T Y M O D E L B E Yo N D 4 Aumentioning

confidence: 99%

Comets beyond 4 au: How pristine are Oort nuclei?

Fulle

Lazzarin

Forgia

et al. 2022

Monthly Notices of the Royal Astronomical Society

View full text Add to dashboard Cite

The ESA mission Comet Interceptor will target an Oort or interstellar comet during its first approach to the Sun. Meanwhile, the Vera Rubin LSST Survey will observe hundreds of active comets per month beyond 4 au from the Sun, where water vapor pressure is expected to be too low to eject dust. We discuss observations of dust tails at heliocentric distances larger than 4 au in order to retrieve the physical parameters driving cometary activity beyond Jupiter by means of a probabilistic tail model, which is consistent with the activity model defining the gas coma parameters due to the sublimation of carbon monoxide, molecular oxygen, methane, ethane and carbon dioxide since the activity onset at 85 au from the Sun. We find that: (i) All the observed dust tails are consistent with the adopted activity model; (ii) The tail fits depend on three free parameters only, all correlated to the nucleus size; (iii) Tail fits are always improved by anisotropic dust ejection, suggesting activity of Oort nuclei dominated by seasons; (iv) Inbound seasons suggest cometary activity before the ejection of protocomets into the Oort cloud, as predicted by the activity model; (v) Oort nuclei larger than 1 km may be characterized by a fallout up to ≈100 m thick deposited during ≈60 yr inbound; (vi) On the other side, Oort nuclei smaller than 1 km may appear more pristine than Jupiter Family Comets when observed at 1 au from the Sun.

show abstract

On the similarity of dust flows in the inner coma of comets

Cited by 10 publications

References 16 publications

Dynamics of irregularly-shaped cometary particles subjected to outflowing gas and solar radiative forces and torques

Dynamics of irregularly-shaped cometary particles subjected to outflowing gas and solar radiative forces and torques

Determining the dust environment of an unknown comet for a spacecraft flyby: The case of ESA’s Comet Interceptor mission

Comets beyond 4 au: How pristine are Oort nuclei?

Contact Info

Product

Resources

About