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Analysing greenhouse gas emissions of an astronomical institute is a first step to reducing its environmental impact. Here, we break down the emissions of the Max Planck Institute for Astronomy in Heidelberg and propose measures for reductions.

In this study we present an analysis of the performance and properties of the quasi-periodic (QP) GP kernel, which is the multiplication of the squared-exponential kernel by the exponential-sine-squared kernel, based on an extensive set of synthetic RVs, into which the signature of activity was injected. We find that while the QP-GP rotation parameter matches the simulated rotation period of the star, the length scale cannot be directly connected to the spot lifetimes on the stellar surface. Regarding the setup of the priors for the QP-GP, we find that it can be advantageous to constrain the QP-GP hyperparameters in different ways depending on the application and the goal of the analysis. We find that a constraint on the length scale of the QP-GP can lead to a significant improvement in identifying the correct rotation period of the star, while a constraint on the rotation hyperparameter tends to lead to improved planet detection efficiency and more accurately derived planet parameters. Even though for most of the simulations the Bayesian evidence performed as expected, we identified not far-fetched cases where a blind adoption of this metric would lead to wrong conclusions. We conclude that modeling stellar astrophysical noise by using a QP-GP considerably improves detection efficiencies and leads to precise planet parameters. Nevertheless, there are also cases in which the QP-GP does not perform optimally, for example RV variations dynamically evolving on short timescales or a mixture of a very stable activity component and random variations. Knowledge of these limitations is essential for drawing correct conclusions from observational data.

Here we present juliet, a versatile tool for the analysis of transits, radial-velocities, or both. juliet is built over many available tools for the modelling of transits, radial-velocities and stochastic processes (here modelled as Gaussian Processes; GPs) in order to deliver a tool/wrapper which can be used for the analysis of transit photometry and radial-velocity measurements from multiple instruments at the same time, using nested sampling algorithms which allows it to not only perform a thorough sampling of the parameter space, but also to perform model comparison via bayesian evidences. In addition, juliet allows to fit transiting and non-transiting multi-planetary systems, and to fit GPs which might share hyperparameters between the photometry and radial-velocities simultaneously (e.g., stellar rotation periods), which might be useful for disentangling stellar activity in radial-velocity measurements. Nested Sampling, Importance Nested Sampling and Dynamic Nested Sampling is performed with publicly available codes which in turn give juliet multi-threading options, allowing it to scale the computing time of complicated multi-dimensional problems. We make juliet publicly available via GitHub.

Based on recently-taken and archival HARPS, FEROS and HIRES radial velocities (RVs), we present evidence for a new planet orbiting the first ascent red giant star HD33142 (with an improved mass estimate of 1.52\\(\\pm\\)0.03 M\\(_\\odot\\)), already known to host two planets. We confirm the Jovian mass planets HD33142 b and c with periods of \\(P_{\\rm b}\\) = 330.0\\(_{-0.4}^{+0.4}\\) d and \\(P_{\\rm c}\\) = 810.2\\(_{-4.2}^{+3.8}\\) d and minimum dynamical masses of \\(m_{\\rm b}\\sin{i}\\) = 1.26\\(_{-0.05}^{+0.05}\\) M\\(_{\\rm Jup}\\) and \\(m_{\\rm c}\\sin{i}\\) = 0.89\\(_{-0.05}^{+0.06}\\) M\\(_{\\rm Jup}\\). Furthermore, our periodogram analysis of the precise RVs shows strong evidence for a short-period Doppler signal in the residuals of a two-planet Keplerian fit, which we interpret as a third, Saturn-mass planet with \\(m_\\mathrm{d}\\sin{i}\\) = 0.20\\(_{-0.03}^{+0.02}\\) M\\(_{\\rm Jup}\\) on a close-in orbit with an orbital period of \\(P_{\\rm d}\\) =89.9\\(_{-0.1}^{+0.1}\\) d. We study the dynamical behavior of the three-planet system configurations with an N-body integration scheme, finding it long-term stable with the planets alternating between low and moderate eccentricities episodes. We also performed N-body simulations, including stellar evolution and second-order dynamical effects such as planet-stellar tides and stellar mass-loss on the way to the white dwarf phase. We find that planets HD33142 b, c and d are likely to be engulfed near the tip of the red giant branch phase due to tidal migration. These results make the HD33142 system an essential benchmark for the planet population statistics of the multiple-planet systems found around evolved stars.

We report the discovery and orbital characterization of three new transiting warm giant planets. These systems were initially identified as presenting single transit events in the light curves generated from the full frame images of the Transiting Exoplanet Survey Satellite (TESS). Follow-up radial velocity measurements and additional light curves were used to determine the orbital periods and confirm the planetary nature of the candidates. The planets orbit slightly metal-rich late F- and early G-type stars. We find that TOI 4406b has a mass of \\(M_P\\)= 0.30 \\(\\pm\\) 0.04 \\(M_J\\) , a radius of \\(R_P\\)= 1.00 \\(\\pm\\) 0.02 \\(R_J\\) , and a low eccentricity orbit (e=0.15 \\(\\pm\\) 0.05) with a period of P= 30.08364 \\(\\pm\\) 0.00005 d . TOI 2338b has a mass of \\(M_P\\)= 5.98 \\(\\pm\\) 0.20 \\(M_J\\) , a radius of \\(R_P\\)= 1.00 \\(\\pm\\) 0.01 \\(R_J\\) , and a highly eccentric orbit (e= 0.676 \\(\\pm\\) 0.002 ) with a period of P= 22.65398 \\(\\pm\\) 0.00002 d . Finally, TOI 2589b has a mass of \\(M_P\\)= 3.50 \\(\\pm\\) 0.10 \\(M_J\\) , a radius of \\(R_P\\)= 1.08 \\(\\pm\\) 0.03 \\(R_J\\) , and an eccentric orbit (e = 0.522 \\(\\pm\\) 0.006 ) with a period of P= 61.6277 \\(\\pm\\) 0.0002 d . TOI 4406b and TOI 2338b are enriched in metals compared to their host stars, while the structure of TOI 2589b is consistent with having similar metal enrichment to its host star.

TOI-2525 is a K-type star with an estimated mass of M = 0.849\\(_{-0.033}^{+0.024}\\) M\\(_\\odot\\) and radius of R = 0.785\\(_{-0.007}^{+0.007}\\) R\\(_\\odot\\) observed by the TESS mission in 22 sectors (within sectors 1 and 39). The TESS light curves yield significant transit events of two companions, which show strong transit timing variations (TTVs) with a semi-amplitude of a \\(\\sim\\)6 hours. We performed TTV dynamical, and photo-dynamical light curve analysis of the TESS data, combined with radial velocity (RV) measurements from FEROS and PFS, and we confirmed the planetary nature of these companions. The TOI-2525 system consists of a transiting pair of planets comparable to Neptune and Jupiter with estimated dynamical masses of \\(m_{\\rm b}\\) = 0.088\\(_{-0.004}^{+0.005}\\) M\\(_{\\rm Jup.}\\), and \\(m_{\\rm c}\\) = 0.709\\(_{-0.033}^{+0.034}\\) M\\(_{\\rm Jup.}\\), radius of \\(r_b\\) = 0.88\\(_{-0.02}^{+0.02}\\) R\\(_{\\rm Jup.}\\) and \\(r_c\\) = 0.98\\(_{-0.02}^{+0.02}\\) R\\(_{\\rm Jup.}\\), and with orbital periods of \\(P_{\\rm b}\\) = 23.288\\(_{-0.002}^{+0.001}\\) days and \\(P_{\\rm c}\\) = 49.260\\(_{-0.001}^{+0.001}\\) days for the inner and the outer planet, respectively. The period ratio is close to the 2:1 period commensurability, but the dynamical simulations of the system suggest that it is outside the mean motion resonance (MMR) dynamical configuration. TOI-2525 b is among the lowest density Neptune-mass planets known to date, with an estimated median density of \\(\\rho_{\\rm b}\\) = 0.174\\(_{-0.015}^{+0.016}\\) g\\,cm\\(^{-3}\\). The TOI-2525 system is very similar to the other K-dwarf systems discovered by TESS, TOI-2202 and TOI-216, which are composed of almost identical K-dwarf primary and two warm giant planets near the 2:1 MMR.

Analysing greenhouse gas emissions of an astronomical institute is a first step in reducing its environmental impact. Here, we break down the emissions of the Max Planck Institute for Astronomy in Heidelberg and propose measures for reductions.

Context. Characterization of warm giants is crucial to constrain giant planet formation and evolution. Measuring the mass and radius of these planets, combined with their moderated irradiation, allows us to estimate their planetary bulk composition, which is a key quantity to comprehend giant planet formation and structure. Aims. We present the discovery of two transiting warm giant planets orbiting solar-type stars from the Transiting Exoplanet Survey Satellite (TESS), which were characterized by further spectroscopic and photometric ground-based observations. Methods. We performed a joint analysis of photometric data with radial velocities to confirm and characterize TOI-883 b and TOI-899 b, two sub-Saturns orbiting solar-like stars. Results. TOI-883 b and TOI-899 b have masses of \\(0.123 0.012\\) \\(M_J\\) and \\(0.213 0.024\\) \\(M_J\\), radius of \\(0.604 0.028\\) \\(R_J\\) and \\(0.991 0.044\\) \\(R_J\\), periods of \\(10.06\\) d and \\(12.85\\) d and equilibrium temperature of \\(1086 19\\) K and \\(1040 19\\) K, respectively. Conclusions. While having similar masses, orbital periods and stellar host properties, these planets seem to have different internal compositions, which could point to distinct formation histories. Both planets are suitable targets for atmospheric studies to further constrain formation scenarios of planets in the Neptune-Saturn mass range

TOI-2202 b is a transiting warm Jovian-mass planet with an orbital period of P=11.91 days identified from the Full Frame Images data of five different sectors of the TESS mission. Ten TESS transits of TOI-2202 b combined with three follow-up light curves obtained with the CHAT robotic telescope show strong transit timing variations (TTVs) with an amplitude of about 1.2 hours. Radial velocity follow-up with FEROS, HARPS and PFS confirms the planetary nature of the transiting candidate (a\\(_{\\rm b}\\) = 0.096 \\(\\pm\\) 0.002 au, m\\(_{\\rm b}\\) = 0.98 \\(\\pm\\) 0.06 M\\(_{\\rm Jup}\\)), and dynamical analysis of RVs, transit data, and TTVs points to an outer Saturn-mass companion (a\\(_{\\rm c}\\) = 0.155 \\(\\pm\\) 0.003 au, m\\(_{\\rm c}\\)= \\(0.37 \\pm 0.10\\) M\\(_{\\rm Jup}\\)) near the 2:1 mean motion resonance. Our stellar modeling indicates that TOI-2202 is an early K-type star with a mass of 0.82 M\\(_\\odot\\), a radius of 0.79 R\\(_\\odot\\), and solar-like metallicity. The TOI-2202 system is very interesting because of the two warm Jovian-mass planets near the 2:1 MMR, which is a rare configuration, and their formation and dynamical evolution are still not well understood.

We report the discovery and characterization of TOI-1759~b, a temperate (400 K) sub-Neptune-sized exoplanet orbiting the M~dwarf TOI-1759 (TIC 408636441). TOI-1759 b was observed by TESS to transit on sectors 16, 17 and 24, with only one transit observed per sector, creating an ambiguity on the orbital period of the planet candidate. Ground-based photometric observations, combined with radial-velocity measurements obtained with the CARMENES spectrograph, confirm an actual period of \\(18.85019 \\pm 0.00014\\) d. A joint analysis of all available photometry and radial velocities reveal a radius of \\(3.17 \\pm 0.10\\,R_\\oplus\\) and a mass of \\(10.8 \\pm 1.5\\,M_\\oplus\\). Combining this with the stellar properties derived for TOI-1759 (\\(R_\\star = 0.597 \\pm 0.015\\,R_\\odot\\); \\(M_\\star = 0.606 \\pm 0.020\\,M_\\odot\\); \\(T_{\\textrm{eff}} = 4065 \\pm 51\\) K), we compute a transmission spectroscopic metric (TSM) value of over 80 for the planet, making it a good target for transmission spectroscopy studies. TOI-1759 b is among the top five temperate, small exoplanets (\\(T_\\textrm{eq} < 500\\) K, \\(R_p < 4 \\,R_\\oplus\\)) with the highest TSM discovered to date. Two additional signals with periods of 80 d and \\(>\\) 200 d seem to be present in our radial velocities. While our data suggest both could arise from stellar activity, the later signal's source and periodicity are hard to pinpoint given the \\(\\sim 200\\) d baseline of our radial-velocity campaign with CARMENES. Longer baseline radial-velocity campaigns should be performed in order to unveil the true nature of this long period signal.