Further milliarcsecond resolution results on cool giants and binary stars from lunar occultations at Devashtal

• Published in: Monthly notices of the Royal Astronomical Society 2020-10, Vol.498 (2), p.2263-2269
• Main Authors: Richichi, A, Sharma, S, Sinha, T, Pandey, R, Ghosh, A, Ojha, D K, Pandey, A K, Naik, M B
• Format: Article
• Language: English
• ISSN: 0035-8711; 1365-2966
• DOI: 10.1093/mnras/staa2403

ABSTRACT We report on 26 lunar occultation events observed in the context of a programme started at Devasthal in 2017. In addition to the customary observations with the 1.3-m telescope, we report here also the first attempts performed with the TIRCAM2 camera at the 3.6-m Devasthal Optical Telescope in the near-infrared (near-IR). The results consist in the first-time angular diameters for two late-type giants, in a measurement of the well-known asymptotic giant branch pulsating variable SW Vir, and in the measurement of eight small separation binaries one of which is detected for the first time (HR 1860). We also measured the wider binaries SAO 94431 and 55 Tau (twice). The remaining sources were found to be unresolved with upper limits as small as 1 mas. We plan to develop further the high-speed capability of the TIRCAM2 instrument, so as to include in our programme also more near-IR, highly extincted sources.