The HD 93963 A transiting system: A 1.04 d super-Earth and a 3.65 d sub-Neptune discovered by TESS and CHEOPS

We present the discovery of two small planets transiting HD 93963A (TOI-1797), a G0\,V star (M$_*$=1.109\,$\pm$\,0.043\,M$_\odot$, R$_*$=1.043\,$\pm$\,0.009\,R$_\odot$) in visual binary system. combined TESS and CHEOPS space-borne photometry with data from MuSCAT 2, `Alopeke, PHARO, TRES, FIES, SOPHIE. validated spectroscopically confirmed outer planet 93963 Ac, sub-Neptune an orbital period P$_c \approx$ 3.65 d, reported as object interest (TOI) shortly after release Sector 22 data. Ac has mass M$_c = 19.2 \pm 4.1$ M$_{\oplus}$ radius R$_c 3.228 0.059$ R$_{\oplus}$, implying mean density $\rho_c=3.1\pm0.7$ gcm$^{-3}$. The inner object, Ab, is 1.04 d ultra-short (USP) super-Earth that we discovered light curve was not listed TOI, owing to low significance its signal (TESS signal-to-noise ratio $\approx$ 6.7, $+$ transit depth D$_b=141.5 8.5$ ppm). intensively monitored by performing nine observations confirm presence validate Ab first (R$_b 1.35 0.042$ R$_{\oplus}$) USP CHEOPS. Unlike c, significantly detected our radial velocities (M$_b 7.8 3.2$ M$_{\oplus}$). also linear trend Doppler measurements, suggesting possible long-period planet. With V-band magnitude 9.2, A among brightest stars known host planet, making it one most favourable targets for precise measurement via spectroscopy important laboratory test formation, evolution, migration models planetary systems hosting planets.