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The technical progress of the last decades has enabled us to study ever smaller planets with increasing precision. The characterisation of Earth-sized planets is particularly exciting, since they can provide important insights into the formation and development of our own Earth. M-dwarf stars are especially suited to search for Earth-sized planets with the radial velocity (RV) and transit method, because the planetary signals are more pronounced for these stars due to their larger planet-to-star mass and radius ratios. In my dissertation, I deal with the CARMENES spectrograph, which was constructed exactly for this purpose. The first part is an error budget for the visual channel of the spectrograph, in which I investigate what comprises the uncertainty of the measured RVs and what the technical limits of the instrument are. In the second part of the thesis, I present the discovery of two Earth-sized planets using CARMENES observations. The two short-period, Earth-sized planets GJ 3473 b and GJ 3929 b orbit M-dwarf stars and were initially identified as transiting planet candidates by the TESS survey satellite. Our follow-up observations using the RV method confirmed their planetary nature and revealed in the case of GJ 3473 another non-transiting, temperate planet with sub-Neptune mass, GJ 3473 c. Joint modelling of the transit and RV data made it possible to determine precise masses and radii for the two transiting planets. The densities determined from this are most consistent with a MgSiO3 composition for both planets. Due to their short orbital periods and therefore high equilibrium temperatures, both are particularly well suited for future atmospheric characterisation using transit spectroscopy.

We present two small transiting planets with mass measurements orbiting bright mid M dwarfs (GJ 3473, GJ 3929). GJ 3473 b (Kemmer et al. 2020) is a hot, presumably rocky, planet (P = 1.198 d, Mb = 1.86 ± 0.30 Me, and radius, Rb = 1.264 ± 0.050 Re), which is due to its high temperature a particularly attractive target for thermal emission spectroscopy. Further, it is accompanied by another non-transiting planet (Pc = 15.509 ± 0.033 d) that has a minimum mass of Mc sin i = 7.41 ± 0.91 Me. For GJ 3929 b (in prep.) we present a preliminary analysis that yields a period of P = 2.616 d, mass Mb = 2.03 ± 0.59 Me, and radius, Rb = 1.155 ± 0.043 Re. The radial velocity data show evidence for another signal, whose origin is, however, not yet clarified. Both systems add to the TESS level-one science goal to measure the masses for 50 transiting planets with radii smaller than 4 Re., {"references":["Kemmer, J., Stock, S., Kossakowski, D., et al. 2020, A&A, 642, A236","Southworth, J. 2011, MNRAS, 417, 2166","Zeng, L., Jacobsen, S. B., Sasselov, D. D., et al. 2019, Proc. Natl. Acad. Sci USA, 116, 9723"]}

Multi-functional polyethers with ene or diene moieties were prepared via the polymerisation of tailored functional glycidyl ether monomers to create a platform for click chemistry with triazolinediones (TADs). Specifically, two novel monomers (i) 2,4-hexadien-1-yl glycidyl ether (HDEGE) and (ii) citronellyl glycidyl ether (CitroGE), designed to undergo a Diels–Alder or Alder–Ene reaction with TADs, respectively, were synthesized and subsequently transformed into a variety of tailored polyethers, either via the monomer activated method or anionic ring opening polymerisation. Multi-functional copolymers of HDEGE with ethylene oxide, propylene oxide and ethoxy ethyl glycidyl ether as well as ABA and AB poly(ethylene glycol)-based block copolymers with CitroGE are reported to demonstrate the scope of this platform. The ene and diene moieties were reacted with both mono- and bis-funtional TAD compounds to yield quantitative and irreversible modification with adjustable reaction kinetics, ranging from seconds for the HDEGE-based polymers to several minutes for the CitroGE-based polymers. In case of bis-functional TAD compounds, network formation and rapid gelation were achieved. The herein described multi-functional polyethers based on HDEGE and CitroGE are introduced as a platform to enable facile, fast, metal-free and quantitative functionalization of polyethers under mild conditions with an adjustable reaction time span.

We have developed a method to solution process strongly hydrogen-bonded odd nylons into ferroelectric thin films., Ferroelectricity, a bistable ordering of electrical dipoles in a material, is widely used in sensors, actuators, nonlinear optics, and data storage. Traditional ferroelectrics are ceramic based. Ferroelectric polymers are inexpensive lead-free materials that offer unique features such as the freedom of design enabled by chemistry, the facile solution-based low-temperature processing, and mechanical flexibility. Among engineering polymers, odd nylons are ferroelectric. Since the discovery of ferroelectricity in polymers, nearly half a century ago, a solution-processed ferroelectric nylon thin film has not been demonstrated because of the strong tendency of nylon chains to form hydrogen bonds. We show the solution processing of transparent ferroelectric thin film capacitors of odd nylons. The demonstration of ferroelectricity, as well as the way to obtain thin films, makes odd nylons attractive for applications in flexible devices, soft robotics, biomedical devices, and electronic textiles.

Multiple hydroxamic acids are introduced at poly(ethylene glycol) (PEG) via copolymerization of ethylene oxide with a novel epoxide monomer containing a 1,4,2-dioxazole-protected hydroxamic acid (HAAGE). AB- and ABA-type di- and triblock copolymers as well as statistical copolymers of HAAGE and ethylene oxide are prepared in a molecular weight range between 2600 and 12 000 g mol-1 with low dispersities (Ð < 1.2). Cleavage of the acetal protecting group after the polymerization is achieved by mild acidic treatment, releasing multiple free hydroxamic acids tethered to the polyether backbone. The chelation properties of different polymer architectures (statistical versus diblock and ABA triblock) are investigated and compared with regard to the number and position of hydroxamic acids. Separation of the hydroxamic acid units by at least 5 ethylene glycol monomer units is found to be essential for high Fe(III) binding efficiency, while block copolymers are observed to be the best-suited architecture for polymer network and hydrogel formation via Fe(III) chelation.

Hyperbranched poly(butylene oxide) polyols have been synthesized by multibranching anionic ring-opening copolymerization of 1,2-butylene oxide and glycidol. Systematic variation of the composition from 24 to 74% glycidol content resulted in a series of moderately distributed copolymers (Đ = 1.41–1.65, SEC), albeit with limited molecular weights in the solvent-free batch process in the range of 900–1300 g mol–1 (apparent Mn determined by SEC with PEG standards). In situ monitoring of the copolymerization kinetics by 1H NMR showed a pronounced compositional drift with respect to the monomer feed, indicating a strongly tapered microstructure caused by the higher reactivity of glycidol. In the case of slow monomer addition considerably higher apparent molecular weights up to 8500 g mol–1 were obtained (SEC). By alteration of the comonomer ratio, aqueous solubility of the hyperbranched copolymers could be tailored, resulting in well-defined cloud points between 20 and 84 °C. Glass transition temperatures betwe...

Water-soluble copolymers of ferrocenyl glycidyl ether (fcGE) and glycidol were prepared via anionic ring-opening multibranching polymerization (ROMBP). The resulting hyperbranched materials with molecular weights (Mn) of 3500 to 12 300 g mol−1 and relatively narrow molecular weight distributions (Mw/Mn = 1.40–1.69) exhibit both temperature- as well as redox-responsive behavior, which was studied via turbidity measurements. The cloud point temperatures (Tc) were adjusted between 45 and 60 °C through variation of the fcGE comonomer content. Additionally, these Tcs can be increased by the addition of an oxidizing agent. The extent of oxidation of the materials was quantified by Mosbauer spectroscopy and can be correlated to the change in the Tcs. Furthermore, the copolymers were investigated via1H and inverse gated (IG) 13C NMR spectroscopy, size exclusion chromatography (SEC), MALDI-ToF mass spectroscopy and differential scanning calorimetry (DSC). The reversible oxidation of the fc moities is demonstrated by cyclic voltammetry.

BACKGROUND: Until recently, hyperbranched polymers were thought to be ill-defined materials that were not useful as building blocks for well-defined complex polymer architectures. It is a current challenge to develop strategies that offer rapid access to well-defined hyperbranched block copolymers. RESULTS: A convenient three-step protocol for the synthesis of double-hydrophilic hyperbranched–linear–hyperbranched ABA-type triblock copolymers based on poly(ethylene oxide) (PEO) and hyperbranched polyglycerol (hbPG) is presented. The Bola-type polymers exhibiting an aliphatic polyether structure were prepared from a linear (lin) linPG-b-PEO-b-linPG precursor triblock. The materials exhibit low polydispersities (Mw/Mn) in the range 1.19–1.45. The molecular weights of the block copolymers range from 6300 to 26 200 g mol−1, varying in the length of both the linear PEO chain as well as the hbPG segments. Detailed characterization of the thermal properties using differential scanning calorimetry demonstrates nanophase segregation of the blocks. CONCLUSION: The first example of well-defined ABA hyperbranched–linear–hyperbranched triblock copolymers with PEO middle block and hbPG A-blocks is presented. The biocompatible nature of the aliphatic polyether blocks renders these materials interesting for biomedical purposes. These new materials are also intriguing with respect to their supramolecular order and biomineralization properties. Copyright © 2009 Society of Chemical Industry

Hyperbranched polyglycerol (PG) is established as one of the few hyperbranched polymers that offer the possibility to control molecular weight up to Mn = 6000 g/mol. This work introduces a facile 2-step strategy that relies on the use of a low molecular weight PG (Mn = 500 and 1000 g/mol) as a macroinitiator for the slow addition of glycidol, permitting to overcome previous limitations concerning molecular weights and molecular weight control. A systematic investigation of the effect of the degree of deprotonation on the control of the polymerization reaction has been carried out. A series of hyperbranched PGs with molecular weights up to Mn = 24000 g/mol has been obtained under fully controlled conditions. The polydispersities of the samples prepared were in the range of 1.3 to 1.8. In summary, we present the first example of a synthetic strategy for a hyperbranched polymer that is now accessible over a broad range of molecular weights (300−24000 g/mol) without the ubiquitous problem of large polydispers...

We report the discovery of a Neptune-like planet (LP 714-47 b, P = 4.05204 d, mb = 30.8 ± 1.5Mpdbl, Rb = 4.7 ± 0.3 Rpdbl) located in the "hot Neptune desert". Confirmation of the TESS Object of Interest (TOI 442.01) was achieved with radial-velocity follow-up using CARMENES, ESPRESSO, HIRES, iSHELL, and PFS, as well as from photometric data using TESS, Spitzer, and ground-based photometry from MuSCAT2, TRAPPIST-South, MONET-South, the George Mason University telescope, the Las Cumbres Observatory Global Telescope network, the El Sauce telescope, the TÜBITAK National Observatory, the University of Louisville Manner Telescope, and WASP-South. We also present high-spatial resolution adaptive optics imaging with the Gemini Near-Infrared Imager. The low uncertainties in the mass and radius determination place LP 714-47 b among physically well-characterised planets, allowing for a meaningful comparison with planet structure models. The host star LP 714-47 is a slowly rotating early M dwarf (Teff = 3950 ± 51 K) with a mass of 0.59 ± 0.02Mpdbl and a radius of 0.58 ± 0.02Rpdbl. From long-term photometric monitoring and spectroscopic activity indicators, we determine a stellar rotation period of about 33 d. The stellar activity is also manifested as correlated noise in the radial-velocity data. In the power spectrum of the radial-velocity data, we detect a second signal with a period of 16 days in addition to the four-day signal of the planet. This could be shown to be a harmonic of the stellar rotation period or the signal of a second planet. It may be possible to tell the difference once more TESS data and radial-velocity data are obtained. © ESO 2020., CARMENES is an instrument for the Centro Astronomico Hispano-Aleman de Calar Alto (CAHA, Almeria, Spain). CARMENES is funded by the German Max-Planck-Gesellschaft (MPG), the Spanish Consejo Superior de Investigaciones Cientificas (CSIC), the European Union through FEDER/ERF FICTS-2011-02 funds, and the members of the CARMENES Consortium (Max-Planck-Institut fur Astronomie, Instituto de Astrofisica de Andalucia, Landessternwarte Konigstuhl, Institut de Ciencies de l'Espai, Institut fur Astrophysik Gottingen, Universidad Complutense de Madrid, Thuringer Landessternwarte Tautenburg, Instituto de Astrofisica de Canarias, Hamburger Sternwarte, Centro de Astrobiologia and Centro Astronomico Hispano-Aleman), with additional contributions by the Spanish Ministry of Economy, the German Science Foundation through the Major Research Instrumentation Programme and DFG Research Unit FOR2544 "Blue Planets around Red Stars", the Klaus Tschira Stiftung, the states of Baden-Wurttemberg and Niedersachsen, and by the Junta de Andalucia. Based on data from the CARMENES data archive at CAB (INTA-CSIC). We acknowledge the use of public TESS Alert data from pipelines at the TESS Science Office and at the TESS Science Processing Operations Center. This research has made use of the Exoplanet Follow-up Observation Program website, which is operated by the California Institute of Technology, under contract with the National Aeronautics and Space Administration under the Exoplanet Exploration Program. Resources supporting this work were provided by the NASA High-End Computing (HEC) Program through the NASA Advanced Supercomputing (NAS) Division at Ames Research Center for the production of the SPOC data products. Some of the observations in the paper made use of the High-Resolution Imaging instrument Zorro. Zorro was funded by the NASA Exoplanet Exploration Program and built at the NASA Ames Research Center by Steve B. Howell, Nic Scott, Elliott P. Horch, and Emmett Quigley. Zorro was mounted on the Gemini South telescope of the international Gemini Observatory, a program of NSF's OIR Lab, which is managed by the Association of Universities for Research in Astronomy (AURA) under a cooperative agreement with the National Science Foundation. on behalf of the Gemini partnership: the National Science Foundation (United States), National Research Council (Canada), Agencia Nacional de Investigacion y Desarrollo (Chile), Ministerio de Ciencia, Tecnologia e Innovacion (Argentina), Ministerio da Ciencia, Tecnologia, Inovacoes e Comunicacoes (Brazil), and Korea Astronomy and Space Science Institute (Republic of Korea). This work makes use of observations from the LCOGT network. This article is based on observations made with the MuSCAT2 instrument, developed by ABC, at Telescopio Carlos Sanchez operated on the island of Tenerife by the IAC in the Spanish Observatorio del Teide. This paper is also based on observations made in the Observatorios de Canarias del IAC with the Nordic Optical Telescope operated on the island of La Palma by NOTSA in the Observatorio del Roque de los Muchachos. Data were partly obtained with the MONET/South telescope of the MOnitoring NEtwork of Telescopes, funded by the Alfried Krupp von Bohlen und Halbach Foundation, Essen, and operated by the Georg-August-Universitat Gottingen, the McDonald Observatory of the University of Texas at Austin, and the South African Astronomical Observatory. This research has made use of the NASA Exoplanet Archive, which is operated by the California Institute of Technology, under contract with the National Aeronautics and Space Administration under the Exoplanet Exploration Program. This research made use of Lightkurve, a Python package for Kepler and TESS data analysis (Lightkurve Collaboration 2018). We acknowledge financial support from the Spanish Agencia Estatal de Investigacion of the Ministerio de Ciencia, Innovacion y Universidades and the European FEDER/ERF funds through projects AYA2015-69350-C3-2-P, PGC2018098153-B-C31/C33, AYA2016-79425-C3-1/2/3-P, AYA2018-84089, BES-2017080769, ESP2016-80435-C2-1/2-R, ESP2017-87676-C5-1/2/5-R, Instituto de Astrofisica de Andalucia (SEV-2017-0709), the Generalitat de Catalunya through CERCA programme, the UK Science and Technology Facilities Council through grant ST/P000592/1, the JSPS KAKENHI through grants 17H04574, JP18H01265, and 18H05439, and the JST PRESTO through grant JPMJPR1775, the "la Caixa" INPhINIT Fellowship Grant LCF/BQ/IN17/11620033 for Doctoral studies at Spanish Research Centres of Excellence, V.M.P. acknowledges support from NASA Grant NNX17AG24G, Support for this work was provided to J.K.T. by NASA through Hubble Fellowship grant HST-HF2-51399.001 awarded by the Space Telescope Science Institute, which is operated by the Association of Universities for Research in Astronomy, Inc., for NASA, under contract NAS5-26555. The research leading to these results has received funding from the ARC grant for Concerted Research Actions, financed by the Wallonia-Brussels Federation. TRAPPIST is funded by the Belgian Fund for Scientific Research (Fond National de la Recherche Scientifique, FNRS) under the grant FRFC 2.5.594.09.F, with the participation of the Swiss National Science Foundation (SNF). M.G. and E.J. are FNRS Senior Research Associates. S.D. acknowledges support from the Deutsche Forschungsgemeinschaft under Research Unit FOR2544 "Blue Planets around Red Stars", project no. RE 281/32-1. M.Z. acknowledges support from the Deutsche Forschungsgemeinschaft under DFG RE 1664/12-1 and Research Unit FOR2544 "Blue Planets around Red Stars", project no. RE 1664/14-1. M.S. was supported by the DFG Research Unit FOR2544 "Blue Planets around Red Stars", project no. RE 2694/4-1. I.J.M.C. and E.M. acknowledge support from the National Science Foundation through grant AST-1824644. B.B. thanks the European Research Council (ERC Starting Grant 757 448-PAMDORA) for their financial support. D.D. acknowledges support from NASA through Caltech/JPL grant RSA-1006130 and through the TESS Guest Investigator Program Grant 80NSSC19K1727. P.P. acknowledges support from NASA (16-APROBES16-0020 and the Exoplanet Exploration Program) and the National Science Foundation (Astronomy and Astrophysics grant 1716202), the Mt Cuba Astronomical Foundation, and George Mason University start-up and instructional equipment funds. The NASA Infrared Telescope Facility is operated by the University of Hawaii under contract NNH14CK55B with the National Aeronautics and Space Administration. M.R.K is supported by the NSF Graduate Research Fellowship, grant No. DGE 1 339 067. M.Y. and H.V.S. thank to TUB.ITAK for a partial support in using T100 telescope with project number 19AT100-1474. J.N.W. thanks the Heising-Simons Foundation for support. D.H. acknowledges support from the Alfred P. Sloan Foundation, the National Aeronautics and Space Administration (80NSSC18K1585, 80NSSC19K0379), and the National Science Foundation (AST-1 717 000). T.D. acknowledges support from MIT's Kavli Institute as a Kavli postdoctoral fellow. This work made use of tpfplotter (developed by J. Lillo-Box, which also made use of the python packages astropy, lightkurve, matplotlib and numpy. Part of this research was carried out at the Jet Propulsion Laboratory, California Institute of Technology, under a contract with the National Aeronautics and Space Administration (NASA). The authors wish to recognise and acknowledge the very significant cultural role and reverence that the summit of Mauna Kea has always had within the indigenous Hawaiian community. We are most fortunate to have the opportunity to conduct observations from this mountain. Finally, we thank the referee for detailed and helpful comments.

Dynamical histories of planetary systems, as well as atmospheric evolution of highly irradiated planets, can be studied by characterizing the ultra-short-period planet population, which the TESS mission is particularly well suited to discover. Here, we report on the follow-up of a transit signal detected in the TESS sector 19 photometric time series of the M3.0 V star TOI-1685. We confirm the planetary nature of the transit signal, which has a period of Pb = 0.6691403+0.0000023-0.0000021 d, using precise radial velocity measurements taken with the CARMENES spectrograph. From the joint photometry and radial velocity analysis, we estimate the following parameters for TOI-1685 b: a mass of Mb = 3.78+0.63- 0.63 M⊕, a radius of Rb = 1.70+0.07- 0.07 R⊕, which together result in a bulk density of ρb = 4.21+0.95-0.82 g/cm3, and an equilibrium temperature of Teq = 1069 +16-16 K. TOI-1685 b is the least dense ultra-short period planet around an M dwarf known to date. TOI-1685 b is also one of the hottest transiting super-Earth planets with accurate dynamical mass measurements, which makes it a particularly attractive target for thermal emission spectroscopy. Additionally, we report with moderate evidence a further non-transiting planet candidate in the system, TOI-1685[c], with an orbital period of Pc = 9.02+0.10- 0.12 d., {"references":["Espinoza et al. 2019, adsurl: https://ui.adsabs.harvard.edu/abs/2019MNRAS.490.2262E","Zeng et al. 2019, adsurl:https://ui.adsabs.harvard.edu/abs/2019PNAS..116.9723Z","Zeng et al. 2016, adsurl: http://adsabs.harvard.edu/abs/2016ApJ...819..127Z","Southworth, J. 2011, adsurl: http://adsabs.harvard.edu/abs/2011MNRAS.417.2166S","Martínez-Rodríguez et al. 2019, adsurl: https://ui.adsabs.harvard.edu/abs/2019ApJ...887..261M"]}