Circumbinary planet study around NSVS 14256825

The period variability of (O-C) diagram of an eclipsing binary, NSVS 14256825, which is composed of a hot subdwarf type OB star (sdOB) and a main-sequence low-mass type M star (dM) in close orbit with period P=0.110374 days, previously showed sinusoidal signal cause by the light travel time effects. This signal can be caused by the presence of third bodies. We re-examined (O-C) diagram of the system. We combined eclipse timings from published data and the data taken from ULTRASPEC at 2.4 m at Thai National Telescope on November 2018. From the fitting model, the parameters of the third body in NSVS 14256825 system are obtained

Revisiting the transit timing and atmosphere characterization of the Neptune-mass planet HAT-P-26 b

We present a transit-timing variation (TTV) and planetary atmosphere analysis of the Neptune-mass planet HAT-P-26 b. We present a new set of 13 transit light curves from optical ground-based observations and combine them with light curves from the Wide Field Camera 3 on the Hubble Space Telescope, the Transiting Exoplanet Survey Satellite, and previously published ground-based data. We refine the planetary parameters of HAT-P-26 b and undertake a TTV analysis using 33 transits obtained over seven years. The TTV analysis shows an amplitude signal of 1.98 ± 0.05 minutes, which could result from the presence of an additional ∼0.02 MJup planet at a 1:2 mean-motion resonance orbit. Using a combination of transit depths spanning optical to near-infrared wavelengths, we find that the atmosphere of HAT-P-26 b contains ${2.4}_{-1.6}^{+2.9}$% H2O with a derived temperature of ${590}_{-50}^{+60}$ K

GRANDMA observations of advanced LIGO’s and advanced Virgo’s third observational campaign

International audienceGRANDMA (Global Rapid Advanced Network Devoted to the Multi-messenger Addicts) is a network of 25 telescopes of different sizes, including both photometric and spectroscopic facilities. The network aims to coordinate follow-up observations of gravitational-wave (GW) candidate alerts, especially those with large localization uncertainties, to reduce the delay between the initial detection and the optical confirmation. In this paper, we detail GRANDMA’s observational performance during Advanced LIGO/Advanced Virgo Observing Run 3 (O3), focusing on the second part of O3; this includes summary statistics pertaining to coverage and possible astrophysical origin of the candidates. To do so, we quantify our observation efficiency in terms of delay between GW candidate trigger time, observations, and the total coverage. Using an optimized and robust coordination system, GRANDMA followed-up about 90 per cent of the GW candidate alerts, that is 49 out of 56 candidates. This led to coverage of over 9000 deg^2 during O3. The delay between the GW candidate trigger and the first observation was below 1.5 h for 50 per cent of the alerts. We did not detect any electromagnetic counterparts to the GW candidates during O3, likely due to the very large localization areas (on average thousands of degrees squares) and relatively large distance of the candidates (above 200 Mpc for 60 per cent of binary neutron star, BNS candidates). We derive constraints on potential kilonova properties for two potential BNS coalescences (GW190425 and S200213t), assuming that the events’ locations were imaged