Benchmarking the power of amateur observatories for TTV exoplanets detection

This document is the Accepted Manuscript version of the following article: Roman v. Baluev, et al, ‘Benchmarking the power of amateur observatories for TTV exoplanets detection’, Monthly Notices of the Royal Astronomical Society, Vol. 450(3): 3101-3113, first published online 9 May 2015. The version of record is available at doi: https://doi.org/10.1093/mnras/stv788 © 2015 The Authors. Published by Oxford University Press on behalf of the Royal Astronomical Society.We perform an analysis of ~80000 photometric measurements for the following 10 stars hosting transiting planets: WASP-2, -4, -5, -52, Kelt-1, CoRoT-2, XO-2, TrES-1, HD 189733, GJ 436. Our analysis includes mainly transit lightcurves from the Exoplanet Transit Database, public photometry from the literature, and some proprietary photometry privately supplied by other authors. Half of these lightcurves were obtained by amateurs. From this photometry we derive 306 transit timing measurements, as well as improved planetary transit parameters. Additionally, for 6 of these 10 stars we present a set of radial velocity measurements obtained from the spectra stored in the HARPS, HARPS-N, and SOPHIE archives using the HARPS-TERRA pipeline. Our analysis of these TTV and RV data did not reveal significant hints of additional orbiting bodies in almost all of the cases. In the WASP-4 case, we found hints of marginally significant TTV signals having amplitude 10-20 sec, although their parameters are model-dependent and uncertain, while radial velocities did not reveal statistically significant Doppler signals.Peer reviewe

On the representation of the gravitational potential of several model bodies

Laplace series with respect to spherical functions Yn(θ, λ) represents now a most popular form of the gravitational potential representation for a compact body T in the outer space in spherical coordinates r, θ, λ. There exists a well-known estimate Yn Cn−5/2, C = const, n 1 of the Chebyshevian norm (maximum of the modulus) for bodies of irregular structure. In the present paper an explicit representation of Yn(θ, λ) for several model bodies is obtained. The indicated estimate Yn is valid under the exact exponent 5/2 for all cases except one. If the segment touches the enveloping sphere, then Yn decreases much faster. Namely, Yn Cn−5/2pn, C = const, n 1. The quantity p < 1 equals to the distance from the origin of coordinates to the edge of the segment expressed in radii of the enveloping sphere. The exactness of exponent 5/2 is valid in common case by examples of bodies which more or less reminiscent of real celestial bodies. Refs 16. Figs 6.Работа выполнена при финансовой поддержке Постановления №211 Правительства Российской Федерации (контракт №02. A03.21.0006), РФФИ (грант 14-02-00804) и Программы проведения фундаментальных исследований СПбГУ по приоритетным направлениям (грант 6.37.341.2015)