CCD PHOTOMETRIC SURVEY FOR VARIABLE STARS IN CYGNUS AND GEMINI: THIRTY-NINE NEW DISCOVERIES FROM THE OSSERVATORIO ASTRONOMICO NASTRO VERDE (MPC C82)

Abstract

I present the results of a long-term CCD photometric monitoring programme carried out at the Osservatorio Astronomico "Nastro Verde" (MPC Code C82), Sorrento, Italy, targeting known variable stars in two constellations: Cygnus (nine fields plus one adjacent field in Lacerta, 2012–2018) and Gemini (four fields, 2017–2019). For four previously catalogued variables – OO Cyg (EW), V1111 Cyg (RRAB/BL), V2884 Cyg (EB) and GR Gem (EA) – I provide revised periods and epochs. In addition, thirty-nine new variable stars were discovered and submitted to the AAVSO International Variable Star Index (VSX): in Cygnus, 32 new variables of types EW, EB, EA, RRAB, RRC, DSCT, DSCTC and HADS; in Gemini, 7 new EWtype eclipsing binaries. All 43 programme objects are listed in Tables 1 and 2. A colour-magnitude diagram based on Gaia DR3 photometry, with individual BailerJones (2021) distances and individual Gaia DR3 GSP-Phot reddening for each star, is presented for both samples.