Oleksiy Golubov

V. N. Karazin Kharkiv National University · Department of Theoretical Nuclear Physics

The tangential YORP effect is a radiation pressure torque produced by asymmetric thermal emission by structures on the asteroid surface. As such structures, previous works considered boulders of different shapes lying on the surface of the asteroid. We study the tangential YORP produced by the rough interface of the asteroid's regolith. We create a...

An asteroid pair can be described as two asteroids with highly similar heliocentric orbits that are genetically related but not gravitationally bound. They can be produced by asteroid collisions or rotational fission. Although over 200 asteroid pairs are known, many more are remaining to be identified, especially among the newly discovered asteroid...

The Yarkovsky--O'Keefe--Radzievskii--Paddack (YORP) effect governs the spin evolution of small asteroids. The axial component of YORP, which alters the rotation rate of the asteroid, is mostly independent of its thermal inertia, while the obliquity component is very sensitive to the thermal model of the asteroid. Here we develop a semi-analytic the...

Any population of asteroids, like asteroid families, will disperse in semi-major axis due to the Yarkovsky effect. The amount of drift is modulated by the asteroid spin state evolution which determines the balance between the diurnal and seasonal Yarkovsky force. The asteroid's spin state is, in turn, controlled in part by the YORP effect. The othe...

We observed the near-Earth asteroid (101955) Bennu from the ground in 1999 and 2005, and with the Hubble Space Telescope (HST) in 2012, to constrain its rotation rate. The data reveal an acceleration of 2.64 ± 1.05 × 10 ⁻⁶ deg/day ² , which could be due to a change in the moment of inertia of Bennu or to spin up from the Yarkovsky-O'Keefe-Radzievsk...

Here, we discuss the YORP equilibria, to which asteroids can come as the result of their evolution due to the YORP effect.

Aims. We construct the rotation curve of the Milky Way in the extended solar neighbourhood using a sample of Sloan Extension for Galactic Understanding and Exploration (SEGUE) G-dwarfs. We investigate the rotation curve shape for the presence of any peculiarities just outside the solar radius as has been reported by some authors. Methods. Using the...

Context. Tangential YORP is a thermophysical effect that can alter the rotation rate of asteroids and is distinct from the "normal" YORP effect, but to date has only been studied for asteroids with zero obliquity. Aims. The tangential YORP force produced by spherical boulders on the surface of an asteroid with an arbitrary obliquity is studied. Met...

We propose an analytic model for the normal YORP and diurnal Yarkovsky effects experienced by a convex asteroid. Both the YORP torque and the Yarkovsky force are expressed as integrals of a universal function over the surface of an asteroid. Although in general this function can only be calculated numerically from the solution of the heat conductiv...

In 1-D heat conductivity model, the YORP acceleration is proved to be independent of the asteroid's heat properties. Considering small structures on the surface of an asteroid breaks 1-D model. A new force appears, pulling the asteroid's surface parallel to itself. Its effect on the asteroid's rotation is called tangential YORP, or TYORP.

Tangential YORP, or TYORP, has recently been demonstrated to be an important factor in the evolution of an asteroid's rotation state. It is complementary to normal YORP, or NYORP, which used to be considered previously. While NYORP is produced by non-symmetry in the large-scale geometry of an asteroid, TYORP is due to heat conductivity in stones on...

It has recently been shown that re-emission of absorbed solar light by centimeter- to decimeter-sized structures on the surface of an asteroid can create a component of the recoil force that is parallel to the surface (Golubov & Krugly 2012, ApJL 752: L11). Under certain conditions, the western sides of stones appear to be on average slightly warme...

The determination of the LSR is still a matter of debate. The classical value of the tangential peculiar motion of the Sun with respect to the LSR was challenged in recent years, claiming a significantly larger value. We show that the RAdial Velocity Experiment (RAVE) sample of dwarf stars is an excellent data set to derive tighter boundary conditi...

We use measurements of the rotation curve of the Milky Way by the tangent point method to reconstruct the density model of the Milky Way. The observed inner rotation curve is fitted by a theoretical density model, consisting of a Dehnen bulge, an exponential disc with a hole, and a flattened dark matter halo with a cored isothermal or NFW density p...

RAVE, SEGUE and Hipparcos data are used to study the dynamics of stars in the extended solar neighbourhood. The asymmetric drift of thin disc dwarfs is studied as a function of colour and metallicity. Linear extrapolation of the data falls within the error bars from Aumer & Binney (2009) for local standard of rest. The observed metallicity dependen...

We study the asymmetric drift in the Milky Way with the aid of the RAVE data. Then we apply the deduced asymmetric drift correction to the SEGUE data and reconstruct the behaviour of the rotation curve of the Milky Way in the extended solar neighbourhood. The rotation curve appears to be essentially flat. We supplement our data by tangent point mea...

This Letter discusses how re-emission of absorbed solar light by centimeter- to decimeter-sized structures on the surface of an asteroid can create a component of the recoil force that is parallel to the surface. Under certain conditions, the western sides of stones appears to be on average slightly warmer than their eastern sides, thus experiencin...

Sunlit stone on the asteroid surface experiences a net recoil force directed eastwards that accelerate asteroid rotation. We call this effect the tangential YORP to distinguish it from the normal YORP induced by gross-scale asymmetry of the asteroid.

We use SEGUE and Hipparcos data to restrict the behaviour of the rotation curve of the Milky Way in the solar neighbourhood. Then we construct a density model of the Milky Way which best reproduces the available observations of the rotation curve and is consistent with the density constraints in the solar neighbourhood.

We present a self-consistent vertical disc model of thin and thick disc in the solar vicinity. The model is optimized to fit the local kinematics of main sequence stars by varying the star formation history and the dynamical heating function. The star formation history and the dynamical heating function are not uniquely determined by the local kine...

We use RAVE, SEGUE and Hipparcos data to study the asymmetric drift in the solar neighbourhood. We study the metallicity dependence of the asymmetric drift, discuss the reliability of the local standard of rest, and justify the asymmetric drift correction consistent with our data. SEGUE data are then used to trace the rotation curve of the Galaxy i...

Yarkovsky and YORP effects are important factors of evolution of asteroids. Yarkovsky effect changes orbits of asteroids and drives them to resonances, thus responding for the population of near-Earth asteroids. The YORP effect secularly changes rotational state of asteroids, leads them to disruption limit, thus forming distribution of small astero...