Non-zero Yarkovsky acceleration for near-Earth asteroid (99942) Apophis

AbstractThe leading source of uncertainty to predict the orbital motion of asteroid (99942) Apophis is a non-gravitational acceleration arising from the anisotropic thermal re-emission of absorbed radiation, known as the Yarkovsky effect. Previous attempts to obtain this parameter from astrometry for this object have only yielded marginally small values, without ruling out a pure gravitational interaction. Here we present an independent estimation of the Yarkovsky effect based on optical and radar astrometry which includes observations obtained during 2021. Our numerical approach exploits automatic differentiation techniques. We find a non-zero Yarkovsky parameter, A2 = (−2.899 ± 0.025) × 10−14 au d−2, with induced semi-major axis drift of (−199.0 ± 1.5) m yr−1 for Apophis. Our results provide definite collision probability predictions for the close approaches in 2029, 2036, and 2068.

Download Full-text

Influence of non-gravitational effects on the Centaur upper stage of the Surveyor 2 spacecraft

Journal of Physics Conference Series ◽

10.1088/1742-6596/2103/1/012029 ◽

2021 ◽

Vol 2103 (1) ◽

pp. 012029

Author(s):

A A Martyusheva ◽

A V Devyatkin

Keyword(s):

Solar Radiation Pressure ◽

Close Approach ◽

Major Axis ◽

Semi Major Axis ◽

Maximum Displacement ◽

Gravitational Effects ◽

Yarkovsky Effect ◽

Upper Stage ◽

The Impact ◽

Heliocentric Orbit

Abstract A small near-Earth asteroid, discovered by the Panoramic Survey Telescope and Rapid Response System (Pan-STARRS) on September 17, 2020, turned out to be a part of the Centaur upper stage of the Surveyor 2 spacecraft launched by NASA on September 20, 1966 and subsequently crashed. This object had moved in a heliocentric orbit until it was under the influence of Earth’s gravitational field. As a result, a close approach to the Earth took place at a distance of about 50000 km on December 1, 2020. Despite the fact that the Centaur escaped back into a new orbit around the Sun in March 2021, it is of special interest for research, in particular, to consider the impact of non-gravitational effects on its orbital characteristics. Thus, it was calculated that the maximum displacement of the object trajectory due to the influence of solar radiation pressure over 15 years (the next close approach will take place in 2036) can be about 10.3-13.5 km, depending on the albedo. Estimations of the Yarkovsky effect showed that the magnitude of the expected change in the semi-major axis of Centaur’s orbit is from -8.1 • 10−13 to 1.6 10−13, depending on the angle of its rotation.

Download Full-text

Direct Detections of the Yarkovsky Effect: Status and Outlook

Proceedings of the International Astronomical Union ◽

10.1017/s1743921315008790 ◽

2015 ◽

Vol 10 (S318) ◽

pp. 250-258 ◽

Cited By ~ 2

Author(s):

Steven R. Chesley ◽

Davide Farnocchia ◽

Petr Pravec ◽

David Vokrouhlický

Keyword(s):

Mass Loss ◽

Bulk Density ◽

Observational Data ◽

Orbital Motion ◽

Thermal Inertia ◽

Weak Signal ◽

Earth Asteroid ◽

Yarkovsky Effect ◽

A Value ◽

Special Category

AbstractWe report the current results on a comprehensive scan of the near-Earth asteroid catalog for evidence of the Yarkovsky effect in the orbital motion of these bodies. While most objects do not have sufficient observational data to reveal such slight acceleration, we do identify 42 asteroids with a “valid” detection of the Yarkovsky effect, i.e., those with a signal at least 3 times greater than the formal uncertainty and a value compatible with the Yarkovsky mechanism.We also identify a special category of non-detection, which we refer to as “weak signal,” where the objects are of a size that would permit a clear detection if the Yarkovsky effect is maximized, and yet the orbit is clearly incompatible with such accelerations. The implication is that the Yarkovsky effect is reduced in these cases, presumably due to mid-range obliquity, but possibly also due to size, bulk density, thermal inertia, albedo, or spin rate markedly different from assumptions.Finally, there are a number of asteroids showing a significant signal for nongravitational acceleration, and yet with a magnitude too great to be attributed to the Yarkovsky effect. We term these “spurious detections” because most are due to erroneous optical astrometry, often involving a single isolated night from precovery observations. Some cases may be due to other nongravitational accelerations, such as outgassing, mass loss, or micro-meteoroid flux.

Download Full-text

Extended photometric survey of near-Earth objects

Astronomy and Astrophysics ◽

10.1051/0004-6361/202038968 ◽

2020 ◽

Vol 644 ◽

pp. A23

Author(s):

S. Ieva ◽

E. Dotto ◽

E. Mazzotta Epifani ◽

D. Perna ◽

C. Fanasca ◽

...

Keyword(s):

Major Axis ◽

Semi Major Axis ◽

Yarkovsky Effect ◽

La Palma ◽

Physical Information ◽

Interesting Correlation ◽

Rapid Characterization ◽

First Time ◽

Near Earth Objects

Context. The near-Earth objects (NEOs), whose proximity makes them the most accessible bodies in the Solar System, allow us to sample asteroids from tens of kilometers down to objects of a few meters in size. However, while the physical properties for the largest bodies are mostly known, we have very little physical information regarding the small NEOs. These objects today represent the overall majority among the ~2500 new discoveries each year, but they are usually only bright enough to be observable during their close approaches. Aims. Our aim was to extend our survey that started in 2015 on the NEO population, using ground-based observations to characterize the fainter (and typically smaller) NEOs observable each night. Methods. We performed BVRIz photometry of NEOs, making use of the DOLORES instrument at the Telescopio Nazionale Galileo (TNG, La Palma, Spain) and the Asiago Schmidt telescope (Italy), in order to derive visible color indexes and the taxonomic classification for each target in our sample. Results. We taxonomically classified 51 new NEOs for the first time. Together with data obtained in our previous work and collected by other surveys available online, we analyzed an extended sample of 1081 individual NEOs. While the overall majority of them belong to the S-complex, our analysis of the taxonomic distribution found a larger contribution for dark bodies going toward larger H, suggesting that they could be more abundant among the fainter NEOs. Moreover, we find an interesting correlation between semi-major axis and diameter, which could be in part related to the Yarkovsky effect. Rapid characterization of the fainter NEO population shortly after their discovery will be crucial in the future, before those bodies become too faint to be observed, or lost forever.

Download Full-text

The Stein 2051 System

International Astronomical Union Colloquium ◽

10.1017/s0252921100052490 ◽

1977 ◽

Vol 33 ◽

pp. 93-93

Author(s):

K. Aa. Strand

Keyword(s):

Spectral Type ◽

White Dwarf ◽

Orbital Motion ◽

Binary Star ◽

Major Axis ◽

Mass Ratio ◽

Semi Major Axis ◽

Naval Observatory ◽

Red Dwarfs ◽

The Individual

AbstractAn investigation is currently being made of the parallax, proper motion, orbital motion, and mass ratio of the nearby binary star Stein 2051 [04h 11m.4, + 58°49’; (1900); mv = 11.08 and 12.44] based upon photographs taken with the Sproul Observatory 61-cm refractor, the 155-cm astrometric reflector of the U.S. Naval Observatory, and the 33-cm Vatican Carte du Ciel astrograph.A parallax of 0”185 reduced to absolute has been obtained from the material of the Sproul and Naval Observatories which covers the period 1965 to 1975.Since an arc of only 64° in the orbital motion of the visible components has been described from the 1908 epoch of the earliest Vatican plate, and since the separation has increased from 6.” 3 at that time to 7.“ 3 at present and still on the increase, the period of the orbit can only be roughly estimated to be in excess of 300 years.With all plates measured in the same reference frame it has been possible to determine the individual motions of the two components and the mass ratio between them. Preliminary results indicate a perturbation in the orbital motion of the red component with a period of 20 years and a semi-major axis of 0’.’065. The mass ratio between the red dwarf system and the white dwarf is 0.5.A mass of 0.22 M⊙ of the red component has been determined based upon comparison of its luminosity (Mv = 12.42) with the red dwarfs Krüger 60 A (Mv = 11.82), o2 Eri C (Mv = 12.73) and Krüger 60 B (Mv = 13.48) which have the same spectral type (M4) and known masses of 0.26, 0.19, and 0.16 respectively in units of solar masses. Its dark compainion has a mass of 0.02 M⊙ The white dwarf of spectral type DC and Mv = 13.78 has a mass of 0.48 M⊙ as determined from the mass ratio of 0.5 mentioned above.

Download Full-text

Dynamical evolution of asteroid pairs in the vicinity of resonances

Астрономия и исследование космического пространства: Всероссийская с международным участием научная конференция студентов и молодых ученых, посвященная памяти Полины Евгеньевны Захаровой ◽

10.15826/b978-5-7996-3229-8.40 ◽

2021 ◽

Author(s):

A. E. Potoskuev ◽

◽

E. D. Kuznetsov ◽

Keyword(s):

Equations Of Motion ◽

Dynamical Evolution ◽

Major Axis ◽

Time Interval ◽

Orbital Elements ◽

Semi Major Axis ◽

Mean Motion Resonances ◽

Mean Motion ◽

Yarkovsky Effect ◽

Numerical Integrations

Dynamical evolution of asteroid pairs in close orbits near Jovian mean motion resonances (3 : 1, 4 : 1, 5 : 2, 7 : 3) has been researched by means of numerical integrations of the equations of motion over 1 Myr time interval in the future. Initial orbital elements’ uncertainty and semi-major axis drift due to the Yarkovsky effect significantly affect orbit modification with time, especially for objects originally situated in the vicinity of resonances. Passing through a resonance generally leads to orbital distance growth.

Download Full-text

Yarkovsky Effect on the Orbital Dynamics of 1566 Icarus Asteroid

Indonesian Journal of Physics ◽

10.5614/itb.ijp.2019.30.1.2 ◽

2019 ◽

Vol 30 (1) ◽

pp. 6-13

Author(s):

Niken Rara Galih Amithya Parastuti ◽

Endang Soegiartini

Keyword(s):

Numerical Integration ◽

Radiation Force ◽

Major Axis ◽

Time Span ◽

Orbital Dynamics ◽

Semi Major Axis ◽

Newtonian Gravitation ◽

Yarkovsky Effect ◽

N Body Problem ◽

To Receive

The orbital dynamic of small objects is an n-body problem that can not be solve by analitically, it is needed to use numerical integration to find the solution instead. This work is about orbital dynamic of asteroid 1566 Icarus under Classical Newtonian gravitation and if thermal effect (Yarkovsky effect) is included. Yarkovsky Effect is a thermal radiation force resulted from time span of small rotating objects to receive heat from the Sun and then re-radiates it. The Yarkovsky Effect is working optimum for objects with diameter from 10 cm up to 10 km, and now is implemented to Asteroid 1566 Icarus with diameter 1.3 km which are member of Apollo and Earth crosser object. This Asteroid is called Earth crosser due to its orbit is crossing Earth’s orbit. With semi major axis a  1.078 au and eccentricity e  0.827, asteroid 1566 Icarus has perihelion distance q = 0.18674 au or less than semi major axis of Mercury. Due to that reason, Yarkovsky effect was considered to be applied on the orbital dynamics of asteroid 1566 Icarus. Due to sensitivity in input-data of numerical integration for n-body, one hundred simulation preliminary data were made as input in numerical integration process, therefore, 100 clones of Asteroid 1566 Icarus are gathered. Cloning process was conducted by using random number from Asteroid 1566 Icarus orbital elements at epoch 2456800.5 (23 May 2014) to standard deviation . The integration then later conducted within 105 years time span from the epoch. The result shown that the orbital dynamics of asteroid 1566 Icarus with Yarkovsky effect is still within the range of 100 clones of asteroid 1566 Icarus. Thereby, within 105 years, Yarkovsky effect does not change the orbital dynamic of asteroid 1566 Icarus globally, except for two phenomenon between close encounter with planet.

Download Full-text

Post-conjunction detection of β Pictoris b with VLT/SPHERE

Astronomy and Astrophysics ◽

10.1051/0004-6361/201834302 ◽

2019 ◽

Vol 621 ◽

pp. L8 ◽

Cited By ~ 21

Author(s):

A.-M. Lagrange ◽

A. Boccaletti ◽

M. Langlois ◽

G. Chauvin ◽

R. Gratton ◽

...

Keyword(s):

Orbital Motion ◽

Angular Separation ◽

Major Axis ◽

Point Of View ◽

Semi Major Axis ◽

Southwestern Part ◽

Orbital Parameters ◽

Very Large Telescope ◽

Orbital Periods

Context. With an orbital distance comparable to that of Saturn in the solar system, β Pictoris b is the closest (semi-major axis ≃9 au) exoplanet that has been imaged to orbit a star. Thus it offers unique opportunities for detailed studies of its orbital, physical, and atmospheric properties, and of disk-planet interactions. With the exception of the discovery observations in 2003 with NaCo at the Very Large Telescope (VLT), all following astrometric measurements relative to β Pictoris have been obtained in the southwestern part of the orbit, which severely limits the determination of the planet’s orbital parameters. Aims. We aimed at further constraining β Pictoris b orbital properties using more data, and, in particular, data taken in the northeastern part of the orbit. Methods. We used SPHERE at the VLT to precisely monitor the orbital motion of beta β Pictoris b since first light of the instrument in 2014. Results. We were able to monitor the planet until November 2016, when its angular separation became too small (125 mas, i.e., 1.6 au) and prevented further detection. We redetected β Pictoris b on the northeast side of the disk at a separation of 139 mas and a PA of 30° in September 2018. The planetary orbit is now well constrained. With a semi-major axis (sma) of a = 9.0 ± 0.5 au (1σ), it definitely excludes previously reported possible long orbital periods, and excludes β Pictoris b as the origin of photometric variations that took place in 1981. We also refine the eccentricity and inclination of the planet. From an instrumental point of view, these data demonstrate that it is possible to detect, if they exist, young massive Jupiters that orbit at less than 2 au from a star that is 20 pc away.

Download Full-text

Detection and Characterization of earth-like Planets

International Astronomical Union Colloquium ◽

10.1017/s0252921100014810 ◽

1997 ◽

Vol 161 ◽

pp. 299-311 ◽

Cited By ~ 22

Author(s):

Jean Marie Mariotti ◽

Alain Léger ◽

Bertrand Mennesson ◽

Marc Ollivier

Keyword(s):

Direct Detection ◽

Contrast Ratio ◽

Angular Size ◽

Physical Nature ◽

Major Axis ◽

Infrared Emission ◽

Space Technology ◽

Semi Major Axis ◽

Earth Like Planets ◽

Visible Wavelengths

AbstractIndirect methods of detection of exo-planets (by radial velocity, astrometry, occultations,...) have revealed recently the first cases of exo-planets, and will in the near future expand our knowledge of these systems. They will provide statistical informations on the dynamical parameters: semi-major axis, eccentricities, inclinations,... But the physical nature of these planets will remain mostly unknown. Only for the larger ones (exo-Jupiters), an estimate of the mass will be accessible. To characterize in more details Earth-like exo-planets, direct detection (i.e., direct observation of photons from the planet) is required. This is a much more challenging observational program. The exo-planets are extremely faint with respect to their star: the contrast ratio is about 10−10at visible wavelengths. Also the angular size of the apparent orbit is small, typically 0.1 second of arc. While the first point calls for observations in the infrared (where the contrast goes up to 10−7) and with a coronograph, the latter implies using an interferometer. Several space projects combining these techniques have been recently proposed. They aim at surveying a few hundreds of nearby single solar-like stars in search for Earth-like planets, and at performing a low resolution spectroscopic analysis of their infrared emission in order to reveal the presence in the atmosphere of the planet of CO H2O and O3. The latter is a good tracer of the presence of oxygen which could be, like on our Earth, released by biological activity. Although extremely ambitious, these projects could be realized using space technology either already available or in development for others missions. They could be built and launched during the first decades on the next century.

Download Full-text

Some Special Types of Orbits around Jupiter

Aerospace ◽

10.3390/aerospace8070183 ◽

2021 ◽

Vol 8 (7) ◽

pp. 183

Author(s):

Yongjie Liu ◽

Yu Jiang ◽

Hengnian Li ◽

Hui Zhang

Keyword(s):

Gravity Model ◽

Small Perturbation ◽

Equilibrium Points ◽

Major Axis ◽

Semi Major Axis ◽

Ground Track ◽

The Earth ◽

Degenerate Equilibrium ◽

The Mean ◽

Element Theory

This paper intends to show some special types of orbits around Jupiter based on the mean element theory, including stationary orbits, sun-synchronous orbits, orbits at the critical inclination, and repeating ground track orbits. A gravity model concerning only the perturbations of J2 and J4 terms is used here. Compared with special orbits around the Earth, the orbit dynamics differ greatly: (1) There do not exist longitude drifts on stationary orbits due to non-spherical gravity since only J2 and J4 terms are taken into account in the gravity model. All points on stationary orbits are degenerate equilibrium points. Moreover, the satellite will oscillate in the radial and North-South directions after a sufficiently small perturbation of stationary orbits. (2) The inclinations of sun-synchronous orbits are always bigger than 90 degrees, but smaller than those for satellites around the Earth. (3) The critical inclinations are no-longer independent of the semi-major axis and eccentricity of the orbits. The results show that if the eccentricity is small, the critical inclinations will decrease as the altitudes of orbits increase; if the eccentricity is larger, the critical inclinations will increase as the altitudes of orbits increase. (4) The inclinations of repeating ground track orbits are monotonically increasing rapidly with respect to the altitudes of orbits.

Download Full-text