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We present the discovery of two nearly identically-sized sub-Neptunetransiting planets orbiting HD 63935, a bright ($V=8.6$ mag), sun-like($T_{eff}=5560K$) star at 49 pc. TESS identified the first planet, HD 63935 b(TOI-509.01), in Sectors 7 and 34. We identified the second signal (HD 63935 c)in Keck HIRES and Lick APF radial velocity data as part of our followupcampaign. It was subsequently confirmed with TESS photometry in Sector 34 asTOI-509.02. Our analysis of the photometric and radial velocity data yields arobust detection of both planets with periods of $9.0600 \pm 0.007$ and $21.40\pm 0.0019$ days, radii of $2.99 \pm 0.14$ and $2.90 \pm 0.13$ $R_\oplus$, andmasses of $10.8 \pm 1.8$ and $11.1 \pm 2.4$ $M_\oplus$. We calculate densitiesfor planets b and c consistent with a few percent of the planet mass inhydrogen/helium envelopes. We also describe our survey's efforts to choose thebest targets for JWST atmospheric followup. These efforts suggest that HD 63935b will have the most clearly visible atmosphere of its class. It is the besttarget for transmission spectroscopy (ranked by Transmission SpectroscopyMetric, a proxy for atmospheric observability) in the so-far uncharacterizedparameter space comprising sub-Neptune-sized (2.6 $R_\oplus$ $<$ $R_p$ $<$ 4$R_\oplus$), moderately-irradiated (100 $F_\oplus$ $<$ $F_p$ $<$ 1000$F_\oplus$) planets around G-stars. Planet c is also a viable target fortransmission spectroscopy, and given the indistinguishable masses and radii ofthe two planets, the system serves as a natural laboratory for examining theprocesses that shape the evolution of sub-Neptune planets.

TKS V. Twin sub-Neptunes Transiting the Nearby G Star HD 63935