.
FQ Cir was an ordinary fast He/N classical nova, peaking at V = 10.9. The pre-eruption and post-eruption counterpart was at V = 14.0, making this the smallest known classical nova amplitude, 3.1 mag. The nova light and the counterpart coincide at 0 .'' 034, and the counterpart is a rare hot/blue emission-line star with flickering, so the identification of the quiescent nova is certain. The counterpart is a weak Be main-sequence star, B1 V(n)(e). A coherent photometric period appears in all four TESS Sectors and in the AAVSO post-eruption light curve, as ellipsoidal modulation with an orbital period of 2.041738 days. The companion must have been spun up to a fast rotation, and like all Be stars, a decretion disk is exuded. With the constraints of the blackbody radius and the main sequence, the companion mass is 13.0( -0.5)(+0.2 )M(circle dot), with radius 6.2 +/- 0.2 R-circle dot. This is the discovery of a cataclysmic variable with a high-mass companion, a new class that we call "high-mass cataclysmic variables." The white dwarf mass is 1.25 +/- 0.10 M(circle dot )and must have an accretion disk that supplies fuel for the nova eruption. FQ Cir represents a new mode of accretion in interacting binaries, with Roche lobe overflow from the decretion disk feeding mass into the usual accretion disk around the white dwarf, for disk-to-disk accretion. From the mass budget of the binary, the primary star must have its initial mass be >7.7 M-circle dot, forming an ONe white dwarf, so FQ Cir can never become a Type Ia supernova.
High-resolution imaging is widely used to constrain false-positive scenarios in exoplanet validation, but it is a finite follow-up resource that reaches only a subset of candidates, and its population-level impact on validation outcomes has not been quantified through controlled removal experiments. Using an automated pipeline built on TRICERATOPS, we compute the false-positive probability (FPP) of 443 TESS planet candidates. For the 264 planet candidates with high-resolution imaging observations, we compute FPP with and without the corresponding contrast curves, allowing us to quantify the impact of the additional data. We find that 72
We present multiwavelength observations of the first recorded low state of the intermediate polar BG CMi. Optical monitoring of the source by members of the American Association of Variable Star Observers reveals a decrease of ∼0.5 mag that lasted ∼50 days in early 2025. During the low state the optical timing properties imply that BG CMi underwent a change in accretion mode, as power at the spin frequency ω dramatically dropped. An XMM-Newton observation revealed a substantial decrease in intrinsic absorption and a slight increase in intrinsic X-ray luminosity, compared to archival Suzaku data. Timing analysis of the X-ray light curves shows that power shifted from the orbital frequency Ω (prominent in Suzaku data) to 2Ω in the low-state XMM-Newton data, along with strengthening of certain orbital sidebands. We suggest that BG CMi transitioned to disk-overflow accretion, where the white dwarf accreted matter via both a disk and a stream, the latter becoming more dominant during the low state due to a decrease in the mass and size of the disk.
TOI-1232 is a G dwarf star with a mass of 1.06(-0.06)(+0.07)M(circle dot) , a radius of 1.07 +/- 0.05 R-circle dot, and a slightly higher metallicity than solar of Fe/H = 0.18 +/- 0.05. The star hosts a transiting warm Jovian-mass planet, TOI-1232 b, with an orbital period of P-b=14.256(-0.001)(+0.001 )days, identified with data from multiple sectors of the TESS space telescope. The TESS light curve of TOI-1232 is complex, as it is contaminated by a background eclipsing binary with a period of 1.37 days. TOI-1232 b was firmly confirmed by ground-based transit follow-up campaigns from the Las Cumbres, Hazelwood, Brierfield, and ASTEP observatories. Additionally, the TESS transits of TOI-1232 b exhibit strong transit-timing variations (TTVs) with a superperiod of 235.5 +/- 0.7 days and a semiamplitude of 27 minutes. Radial velocity (RV) follow-up with the FEROS spectrograph confirms the planetary nature of the transiting candidate, while a self-consistent N-body analysis of RVs and TTVs pinpoints the presence of a second outer Saturn-mass companion, TOI-1232 c with a period of P-c=30.356(-0.012)(+0.010) days. The TOI-1232 warm-giant system is particularly important due to the evidence of two massive planets that reside near the 2:1 commensurability but are not locked in a mean-motion resonance. Thanks to TESS, we have revealed a handful of these rare systems. Hence, TOI-1232 is an important addition to understanding the formation and dynamical evolution of such compact, massive, warm giant planets.
We present the TESS-based discoveries of planetary systems orbiting the late G dwarfs TOI-2494 and TOI-5143, each of which harbors a hot giant planet and a smaller interior planet. TOI-2494 hosts a transiting mini-Neptune (P = 2.41 days, RP=2.35-0.15+0.16 R circle plus) and a hot Saturn (P = 8.38 days) with grazing transits, while TOI-5143 hosts a transiting mini-Neptune (P = 2.38 days, RP=2.73-0.17+0.19 R circle plus) and a hot Jupiter (P = 5.21 days) with grazing transits. We measure the masses of TOI-2494 c (80 +/- 19 M circle plus) and TOI-5143 c (208 +/- 14 M circle plus), place upper limits on the masses of the smaller planets, and explore the architectures of the planetary systems. TOI-2494 c and TOI-5143 c join a small but growing number of short-period giant planets known to be flanked by smaller companions. While the absence of close neighbors to most hot Jupiters would be consistent with disruptive dynamical evolution, the presence of nearby small planets in some hot Jupiter systems points to a separate, dynamically quiet formation pathway. In support of this conclusion, we present preliminary evidence that hot giant planets with small nearby companions tend to have low mutual orbital inclinations, consistent with the mutual inclination distribution of the dynamically quiet population of compact systems of multiple super-Earths and mini-Neptunes.
