A satellite orbit drift in binary near-Earth asteroids (66391) 1999 KW4 and (88710) 2001 SL9-Indication of the BYORP effect

Result code in IS VaVaI

<a href="https://www.isvavai.cz/riv?ss=detail&h=RIV%2F67985815%3A_____%2F21%3A00548920" target="_blank" >RIV/67985815:_____/21:00548920 - isvavai.cz</a>

Alternative codes found

RIV/47813059:19630/21:A0000158

Result on the web

<a href="https://doi.org/10.1016/j.icarus.2021.114321" target="_blank" >https://doi.org/10.1016/j.icarus.2021.114321</a>

DOI - Digital Object Identifier

<a href="http://dx.doi.org/10.1016/j.icarus.2021.114321" target="_blank" >10.1016/j.icarus.2021.114321</a>

Result language

angličtina

Original language name

A satellite orbit drift in binary near-Earth asteroids (66391) 1999 KW4 and (88710) 2001 SL9-Indication of the BYORP effect

Original language description

We obtained thorough photometric observations of two binary near-Earth asteroids (66391) Moshup = 1999 KW4 and (88710) 2001 SL9 taken from 2000 to 2019. We modeled the data and derived physical and dynamical properties of the binary systems. For (66391) 1999 KW4, we derived its mutual orbit's pole, semimajor axis and eccentricity that are in agreement with radar-derived values (Ostro et al., 2006. Science, 314, 1276-1280). However, we found that the data are inconsistent with aconstant orbital period and we obtained unique solution with a quadratic drift of the mean anomaly of the satellite of -0.65 ± 0.16 deg./yr2 (all quoted uncertainties correspond to 3sigma). This means that the semimajor axis of the mutual orbit of the components of this binary system, determined a = 2.548 ± 0.015 km by Ostro et al.n(2006), increases in time with a mean rate of 1.2 ± 0.3 cm/yr. For (88710) 2001 SL9, we determined that the mutual orbit has a polenwithin 10° of (L, B) = (302°, -73°) (ecliptic coordinates), and is close to circular (eccentricity < 0.07). The data for this system are also inconsistent with a constant orbital period and we obtained two solutions for the quadratic drift of the mean anomaly: 2.8 ± 0.2 andn5.2 ± 0.2 deg./yr2, implying that the semimajor axis of the mutual orbit of the components (estimated a ~ 1.6 km) decreases in time withna mean rate of -2.8 ± 0.2 or -5.1 ± 0.2 cm/yr for the two solutions, respectively. The expanding orbit of (66391) 1999 KW4 may be explained by mutual tides interplaying with binary YORP (BYORP) effect (McMahon and Scheeres, 2010a. Icarus 209, 494-509). However, a modeling of the BYORP drift using radar-derived shapes of the binary components predicted a much higher value of the orbital drift than the observed one. It suggests that either the radar-derived shape model of the secondary is inadequate for computing the BYORP effect, or thenpresent theory of BYORP overestimates it. It is possible that the BYORP coefficient has instead an opposite sign than predicted, in that case, the system may be moving into an equilibrium between the BYORP and the tides. In the case of (88710) 2001 SL9, the BYORP effect is the only known physical mechanism that can cause the inward drift of its mutual orbit. Together with the binary (175706) 1996 FG3 which has a mean anomaly drift consistent with zero, implying a stable equilibrium between the BYORP effect and mutual body tides (Scheirich et al., 2015. Icarus 245, 56-63), we now have three distinct cases of well observed binary asteroid systems with their long-term dynamical models inferred. They indicate a presence of all the three states of the mutual orbit evolution - equilibrium, expanding and contracting - in the population of near-Earth binary asteroids.n

Czech name

—

Czech description

—

Type

J_imp - Article in a specialist periodical, which is included in the Web of Science database

CEP classification

—

OECD FORD branch

10308 - Astronomy (including astrophysics,space science)

Project

<a href="/en/project/GA20-04431S" target="_blank" >GA20-04431S: Physical and dynamical properties of space mission target asteroids, and their evolutionary paths</a><br>

Continuities

I - Institucionalni podpora na dlouhodoby koncepcni rozvoj vyzkumne organizace

Publication year

2021

Confidentiality

S - Úplné a pravdivé údaje o projektu nepodléhají ochraně podle zvláštních právních předpisů

Name of the periodical

Icarus

ISSN

0019-1035

e-ISSN

1090-2643

Volume of the periodical

360

Issue of the periodical within the volume

May

Country of publishing house

US - UNITED STATES

Number of pages

13

Pages from-to

114321

UT code for WoS article

000629599500004

EID of the result in the Scopus database

2-s2.0-85100736717