Context. Saturn has an excess of irregular moons. This is thought to be the result of past collisional events. Debris produced during such episodes in the neighborhood of a host planet can evolve ...into co-orbitals trapped in quasi-satellite and/or horseshoe resonant states. A recently announced centaur, 2013 VZ70, follows an orbit that could be compatible with those of prograde Saturn’s co-orbitals. Aims. We perform an exploration of the short-term dynamical evolution of 2013 VZ70 to confirm or reject a co-orbital relationship with Saturn. A possible connection with Saturn’s irregular moon population is also investigated. Methods. We studied the evolution of 2013 VZ70 backward and forward in time using N-body simulations, factoring uncertainties into the calculations. We computed the distribution of mutual nodal distances between this centaur and a sample of moons. Results. We confirm that 2013 VZ70 is currently trapped in a horseshoe resonant state with respect to Saturn but that it is a transient co-orbital. We also find that 2013 VZ70 may become a quasi-satellite of Saturn in the future and that it may experience brief periods of capture as a temporary irregular moon. This centaur might also pass relatively close to known irregular moons of Saturn. Conclusions. Although an origin in trans-Neptunian space is possible, the hostile resonant environment characteristic of Saturn’s neighborhood favors a scenario of in situ formation via impact, fragmentation, or tidal disruption as 2013 VZ70 can experience encounters with Saturn at very low relative velocity. An analysis of its orbit within the context of those of the moons of Saturn suggests that 2013 VZ70 could be related to the Inuit group, particularly Siarnaq, the largest and fastest rotating member of the group. Also, the mutual nodal distances of 2013 VZ70 and the moons Fornjot and Thrymr are below the first percentile of the distribution.
Both Centaurs and trans-Neptunian objects (TNOs) are minor bodies found in the outer Solar System. Centaurs are a transient population that moves between the orbits of Jupiter and Neptune, and they ...probably diffused out of the TNOs. TNOs move mainly beyond Neptune. Some of these objects display episodic cometary behaviour; a few percent of them are known to host binary companions. Here, we study the light-curves of two Centaurs—2060 Chiron (1977 UB) and 10199 Chariklo (1997 CU
26
)—and three TNOs—38628 Huya (2000 EB
173
), 28978 Ixion (2001 KX
76
), and 90482 Orcus (2004 DW)—and the colours of the Centaurs and Huya. Precise,
∼
1
%
,
R
-band absolute CCD photometry of these minor bodies acquired between 2006 and 2011 is presented; the new data are used to investigate the rotation rate of these objects. The colours of the Centaurs and Huya are determined using
BVRI
photometry. The point spread function of the five minor bodies is analysed, searching for signs of a coma or close companions. Astrometry is also discussed. A periodogram analysis of the light-curves of these objects gives the following rotational periods:
5.5
±
0.4
h
for Chiron,
7.0
±
0.6
h
for Chariklo,
4.45
±
0.07
h
for Huya,
12.4
±
0.3
h
for Ixion, and
11.9
±
0.5
h
for Orcus. The colour indices of Chiron are found to be
B
−
V
=
0.53
±
0.05
,
V
−
R
=
0.37
±
0.08
, and
R
−
I
=
0.36
±
0.15
. The values computed for Chariklo are
V
−
R
=
0.62
±
0.07
and
R
−
I
=
0.61
±
0.07
. For Huya, we find
V
−
R
=
0.58
±
0.09
and
R
−
I
=
0.64
±
0.20
. Our rotation periods are similar to and our colour values are consistent with those already published for these objects. We find very low levels of cometary activity (if any) and no sign of close or wide binary companions for these minor bodies.
Context.
The paths followed by the known extreme trans-Neptunian objects (ETNOs) effectively avoid direct gravitational perturbations from the four giant planets, yet their orbital eccentricities are ...in the range between 0.69−0.97. Solar system dynamics studies show that such high values of the eccentricity can be produced via close encounters or secular perturbations. In both cases, the presence of yet-to-be-discovered trans-Plutonian planets is required. Recent observational evidence cannot exclude the existence, at 600 AU from the Sun, of a planet of five Earth masses.
Aims.
If the high eccentricities of the known ETNOs are the result of relatively recent close encounters with putative planets, the mutual nodal distances of sizeable groups of ETNOs with their assumed perturber may still be small enough to be identifiable geometrically. In order to confirm or reject this possibility, we used Monte Carlo random search techniques.
Methods.
Two arbitrary orbits may lead to close encounters when their mutual nodal distance is sufficiently small. We generated billions of random planetary orbits with parameters within the relevant ranges and computed the mutual nodal distances with a set of randomly generated orbits with parameters consistent with those of the known ETNOs and their uncertainties. We monitored which planetary orbits had the maximum number of potential close encounters with synthetic ETNOs and we studied the resulting distributions.
Results.
We provide narrow ranges for the orbital parameters of putative planets that may have experienced orbit-changing encounters with known ETNOs. Some sections of the available orbital parameter space are strongly disfavored by our analysis.
Conclusions.
Our calculations suggest that more than one perturber is required if scattering is the main source of orbital modification for the known ETNOs. Perturbers might not be located farther than 600 AU and they have to follow moderately eccentric and inclined orbits to be capable of experiencing close encounters with multiple known ETNOs.
Context. The existence of comets with heliocentric orbital periods close to that of Jupiter (i.e., co-orbitals) has been known for some time. Comet 295P/LINEAR (2002 AR2) is a well-known ...quasi-satellite of Jupiter. However, their orbits are not long-term stable, and they may eventually experience flybys with Jupiter at very close range, close enough to trigger tidal disruptions like the one suffered by comet Shoemaker-Levy 9 in 1992. Aims. Our aim was to study the observed activity and the dynamical evolution of the Jupiter transient co-orbital comet P/2019 LD2 (ATLAS) and its dynamical evolution. Methods. We present results of an observational study of P/2019 LD2 carried out with the 10.4 m Gran Telescopio Canarias (GTC) that includes image analyses using a Monte Carlo dust tail fitting code to characterize its level of cometary activity, and spectroscopic studies to search for gas emission. We also present N-body simulations to explore its past, present, and future orbital evolution. Results. Images of P/2019 LD2 obtained on May 16, 2020, show a conspicuous coma and tail, but the spectrum obtained on May 17, 2020, does not exhibit any evidence of CN, C2, or C3 emission. The comet brightness in a 2.6′′ aperture diameter is r′ = 19.34 ± 0.02 mag, with colors (g′− r′) = 0.78 ± 0.03, (r′− i′) = 0.31 ± 0.03, and (i′− z′) = 0.26 ± 0.03. The temporal dependence of the dust loss rate of P/2019 LD2 can be parameterized by a Gaussian function having a full width at half maximum of 350 days, with a maximum dust mass loss rate of 60 kg s−1 reached on August 15, 2019. The total dust loss rate from the beginning of activity until the GTC observation date (May 16, 2020) is estimated at 1.9 × 109 kg. Comet P/2019 LD2 is now an ephemeral co-orbital of Jupiter, following what looks like a short arc of a quasi-satellite cycle that started in 2017 and will end in 2028. On January 23, 2063, it will experience a very close encounter with Jupiter at perhaps 0.016 au; its probability of escaping the solar system during the next 0.5 Myr is estimated to be 0.53 ± 0.03. Conclusions. Photometry and tail model results show that P/2019 LD2 is a kilometer-sized object, in the size range of the Jupiter-family comets, with a typical comet-like activity most likely linked to sublimation of crystalline water ice and clathrates. Its origin is still an open question. Our numerical studies give a probability of this comet having been captured from interstellar space during the last 0.5 Myr of 0.49 ± 0.02 (average and standard deviation), 0.67 ± 0.06 during the last 1 Myr, 0.83 ± 0.06 over 3 Myr, and 0.91 ± 0.09 during the last 5 Myr.
The distribution of the orbital elements of the known extreme trans-Neptunian objects or ETNOs has been found to be statistically incompatible with that of an unperturbed asteroid population ...following heliocentric or, better, barycentric orbits. Such trends, if confirmed by future discoveries of ETNOs, strongly suggest that one or more massive perturbers could be located well beyond Pluto. Within the trans-Plutonian planets paradigm, the Planet Nine hypothesis has received much attention as a robust scenario to explain the observed clustering in physical space of the perihelia of seven ETNOs which also exhibit clustering in orbital pole position. Here, we revisit the subject of clustering in perihelia and poles of the known ETNOs using barycentric orbits, and study the visibility of the latest incarnation of the orbit of Planet Nine applying Monte Carlo techniques and focusing on the effects of the apsidal anti-alignment constraint. We provide visibility maps indicating the most likely location of this putative planet if it is near aphelion. We also show that the available data suggest that at least two massive perturbers are present beyond Pluto.
ABSTRACT
The innermost section of the Solar system has not been extensively studied because minor bodies moving inside Earth’s orbit tend to spend most of their sidereal orbital periods at very low ...solar elongation, well away from the areas more frequently observed by programs searching for near-Earth objects. The survey carried out from the Zwicky Transient Facility (ZTF) is the first one that has been able to detect multiple asteroids well detached from the direct gravitational perturbation of the Earth–Moon system. ZTF discoveries include 2019 AQ3 and 2019 LF6, two Atiras with the shortest periods among known asteroids. Here, we perform an assessment of the orbital evolution of 2020 AV2, an Atira found by ZTF with a similarly short period but following a path contained entirely within the orbit of Venus. This property makes it the first known member of the elusive Vatira population. Genuine Vatiras, those long-term dynamically stable, are thought to be subjected to the so-called von Zeipel–Lidov–Kozai oscillation that protects them against close encounters with both Mercury and Venus. However, 2020 AV2 appears to be a former Atira that entered the Vatira orbital domain relatively recently. It displays an anticoupled oscillation of the values of eccentricity and inclination, but the value of the argument of perihelion may circulate. Simulations show that 2020 AV2 might reach a 3:2 resonant orbit with Venus in the future, activating the von Zeipel–Lidov–Kozai mechanism, which in turn opens the possibility to the existence of a long-term stable population of Vatiras trapped in this configuration.
On the dynamical evolution of 2002 VE68 de la Fuente Marcos, C.; de la Fuente Marcos, R.
Monthly notices of the Royal Astronomical Society,
21 November 2012, Letnik:
427, Številka:
1
Journal Article
Recenzirano
Odprti dostop
ABSTRACT
The minor planet 2002 VE68 was identified as a quasi‐satellite of Venus shortly after its discovery. At that time its data‐arc span was only 24 d; now it is 2947 d. Here we revisit the topic ...of the dynamical status of this remarkable object as well as look into its dynamical past and explore its future orbital evolution which is driven by close encounters with both the Earth–Moon system and Mercury. In our calculations, we use a Hermite integration scheme, the most updated ephemerides and include the perturbations by the eight major planets, the Moon and the three largest asteroids. We confirm that 2002 VE68 currently is a quasi‐satellite of Venus, and it has remained as such for at least 7000 yr after a close fly‐by with the Earth. Prior to that encounter the object may have already been co‐orbital with Venus or moving in a classical, non‐resonant near‐Earth object (NEO) orbit. The object drifted into the quasi‐satellite phase from an L4 Trojan state. We also confirm that, at aphelion, dangerously close encounters with the Earth (under 0.002 au, well inside the Hill sphere) are possible. We find that 2002 VE68 will remain as a quasi‐satellite of Venus for about 500 yr more and its dynamical evolution is controlled not only by the Earth, with a non‐negligible contribution from the Moon, but by Mercury as well. 2002 VE68 exhibits resonant (or near‐resonant) behaviour with Mercury, Venus and the Earth. Our calculations indicate that an actual collision with the Earth during the next 10 000 yr is highly unlikely but encounters as close as 0.04 au occur with a periodicity of 8 yr.
ABSTRACT
Asymmetric debris discs have been found around stars other than the Sun; asymmetries are sometimes attributed to perturbations induced by unseen planets. The presence or absence of ...asymmetries in our own trans-Neptunian belt remains controversial. The study of sensitive tracers in a sample of objects relatively free from the perturbations exerted by the four known giant planets and most stellar flybys may put an end to this debate. The analysis of the distribution of the mutual nodal distances of the known extreme trans-Neptunian objects (ETNOs) that measure how close two orbits may get to each other could be such a game changer. Here, we use a sample of 51 ETNOs together with random shufflings of this sample and two unbiased scattered-disc orbital models to confirm a statistically significant (62σ) asymmetry between the shortest mutual ascending and descending nodal distances as well as the existence of multiple highly improbably (p < 0.0002) correlated pairs of orbits with mutual nodal distances as low as 0.2 au at 152 au from the Solar system’s barycentre or 1.3 au at 339 au. We conclude that these findings fit best with the notion that trans-Plutonian planets exist.
ABSTRACT YORP-induced fission events may form dynamically coherent pairs or even families of asteroids. The outcome of this process is well documented among members of the main asteroid belt, but not ...in the case of the near-Earth asteroid (NEA) population because their paths randomize very efficiently in a short time-scale. Mean-motion resonances (MMRs) may stabilize the orbits of small bodies by making them avoid close encounters with planets. In theory, YORP-induced fission of asteroids trapped in MMRs can preserve evidence of this process even in near-Earth space. Here, we show that two NEAs, 2017 SN16 and 2018 RY7, are currently following an orbital evolution in which their relative mean longitude does not exhibit any secular increase due to the stabilizing action of the 3:5 MMR with Venus. The mechanism that makes this configuration possible may be at work both in the Solar system and elsewhere. Our analysis suggests that the pair 2017 SN16–2018 RY7 may have had its origin in one out of two mechanisms: YORP-induced splitting or binary dissociation.
ABSTRACT
The chance discovery of the first interstellar minor body, 1I/2017 U1 (‘Oumuamua), indicates that we may have been visited by such objects in the past and that these events may repeat in the ...future. Unfortunately, minor bodies following nearly parabolic or hyperbolic paths tend to receive little attention: over 3/4 of those known have data-arcs shorter than 30 d and, consistently, rather uncertain orbit determinations. This fact suggests that we may have observed interstellar interlopers in the past, but failed to recognize them as such due to insufficient data. Early identification of promising candidates by using N-body simulations may help in improving this situation, triggering follow-up observations before they leave the Solar system. Here, we use this technique to investigate the pre- and post-perihelion dynamical evolution of the slightly hyperbolic comet C/2018 V1 (Machholz–Fujikawa–Iwamoto) to understand its origin and relevance within the context of known parabolic and hyperbolic minor bodies. Based on the available data, our calculations suggest that although C/2018 V1 may be a former member of the Oort Cloud, an origin beyond the Solar system cannot be excluded. If extrasolar, it might have entered the Solar system from interstellar space at low relative velocity with respect to the Sun. The practical feasibility of this alternative scenario has been assessed within the kinematic context of the stellar neighbourhood of the Sun, using data from Gaia second data release, and two robust solar sibling candidates have been identified. Our results suggest that comets coming from interstellar space at low heliocentric velocities may not be rare.
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