Minimum Planet Mass Research Articles

Tilted Circumbinary Planetary Systems as Efficient Progenitors of Free-floating Planets

The dominant mechanism for generating free-floating planets has so far remained elusive. One suggested mechanism is that planets are ejected from planetary systems due to planet–planet interactions. Instability around a single star requires a very compactly spaced planetary system. We find that around binary star systems instability can occur even with widely separated planets that are on tilted orbits relative to the binary orbit due to combined effects of planet–binary and planet–planet interactions, especially if the binary is on an eccentric orbit. We investigate the orbital stability of planetary systems with various planet masses and architectures. We find that the stability of the system depends upon the mass of the highest-mass planet. The order of the planets in the system does not significantly affect stability, but, generally, the most massive planet remains stable and the lower-mass planets are ejected. The minimum planet mass required to trigger the instability is about that of Neptune for a circular orbit binary and a super-Earth of about 10 Earth masses for highly eccentric binaries. Hence, we suggest that planet formation around inclined binaries can be an efficient formation mechanism for free-floating planets. While most observed free-floating planets are giant planets, we predict that there should be more low-mass free-floating planets that are as of yet unobserved than higher-mass planets.

GJ 357 d: Potentially Habitable World or Agent of Chaos?

Multiplanet systems provide important laboratories for exploring dynamical interactions within the range of known exoplanetary system architectures. One such system is GJ 357, consisting of a low-mass host star and three orbiting planets, the outermost (planet d) of which does not transit but lies within the habitable zone (HZ) of the host star. The minimum mass of planet d causes its nature to be unknown, both in terms of whether it is truly terrestrial and if it is a candidate for harboring surface liquid water. Here, we use three sectors of photometry from the Transiting Exoplanet Survey Satellite to show that planets c and d do not transit the host star, and therefore may have masses higher than the derived minimum masses. We present the results for a suite of dynamical simulations that inject an Earth-mass planet within the HZ of the system for three different orbital and mass configurations of planet d. These results show that planet d, rather than being a potentially habitable planet, is likely a source of significant orbital instability for other potential terrestrial planets within the HZ. We find that relatively small eccentricities of planet d cause a majority of the HZ to be unstable for an Earth-mass planet. These results highlight the importance of dynamical stability for systems that are prioritized in the context of planetary habitability.

Vortex weighing and dating of planets in protoplanetary discs

ABSTRACT High-resolution sub-mm observations of some protoplanetary discs reveal non-axisymmetric features, which can often be interpreted as dust concentrations in vortices that form at the edges of gaps carved out by the embedded planets. We use recent results on the time-scale for the planet-driven vortex development in low-viscosity discs to set constraints on the mass and age of a planet producing the vortex. Knowledge of the age of the central star in a vortex-bearing protoplanetary disc system allows one to set a lower limit on the planetary mass at the level of several tens of M⊕. Also, an independent upper limit on the planetary mass would constrain the planetary age, although given the current direct imaging detection limits this constraint is not yet very stringent (it is also sensitively dependent on the disc scale height). These results can be extended to account for the history of planetary mass accretion if it is known. We apply our calculations to several protoplanetary discs harbouring vortex-like features as revealed by ALMA and set limits of (30–50) M⊕ (for disc aspect ratio of 0.1) on the minimum masses of putative planets that could be responsible for these vortices. Our vortex-based method provides an independent way of constraining the properties of embedded planets, complementary to other approaches.

How the planetary eccentricity influences the pebble isolation mass

ABSTRACT We investigate the pebble isolation mass (PIM) for a planet on a fixed eccentric orbit in its protoplanetary disc by conducting a set of two-dimensional (2D) hydrodynamical simulations, including dust turbulent diffusion. A range of planet eccentricities up to e = 0.2 is adopted. Our simulations also cover a range of α-turbulent viscosities, and for each pair {α, e} the PIM is estimated as the minimum planet mass in our simulations such that solids with a Stokes number ≳0.05 do not flow across the planet orbit and remain trapped around a pressure bump outside the planet gap. For α < 10−3, we find that eccentric planets reach a well-defined PIM, which can be smaller than for planets on circular orbits when the eccentricity remains smaller than the disc’s aspect ratio. We provide a fitting formula for how the PIM depends on the planet's eccentricity. However, for α > 10−3, eccentric planets cannot fully stall the pebbles flow and, thus, do not reach a well-defined PIM. Our results suggest that the maximum mass reached by rocky cores should exhibit a dichotomy depending on the disc's turbulent viscosity. While being limited to ${\cal O}(10\, M_\oplus)$ in low-viscosity discs, this maximum mass could reach much larger values in discs with a high turbulent viscosity in the planet vicinity. Our results further highlight that pebble filtering by growing planets might not be as effective as previously thought, especially in high-viscosity discs, with important implications to protoplanetary discs observations.

K2-111: an old system with two planets in near-resonance†

ABSTRACT This paper reports on the detailed characterization of the K2-111 planetary system with K2, WASP, and ASAS-SN photometry, as well as high-resolution spectroscopic data from HARPS-N and ESPRESSO. The host, K2-111, is confirmed to be a mildly evolved (log g = 4.17), iron-poor ([Fe/H] = −0.46), but alpha-enhanced ([α/Fe]=0.27), chromospherically quiet, very old thick disc G2 star. A global fit, performed by using PyORBIT, shows that the transiting planet, K2-111 b, orbits with a period Pb = 5.3518 ± 0.0004 d and has a planet radius of $1.82^{+0.11}_{-0.09}$ R⊕ and a mass of $5.29^{+0.76}_{-0.77}$ M⊕, resulting in a bulk density slightly lower than that of the Earth. The stellar chemical composition and the planet properties are consistent with K2-111 b being a terrestrial planet with an iron core mass fraction lower than the Earth. We announce the existence of a second signal in the radial velocity data that we attribute to a non-transiting planet, K2-111 c, with an orbital period of 15.6785 ± 0.0064 d, orbiting in near-3:1 mean motion resonance with the transiting planet, and a minimum planet mass of 11.3 ± 1.1 M⊕. Both planet signals are independently detected in the HARPS-N and ESPRESSO data when fitted separately. There are potentially more planets in this resonant system, but more well-sampled data are required to confirm their presence and physical parameters.

Planet gap opening across stellar masses

ABSTRACT Annular structures in protoplanetary discs, such as gaps and rings, are now ubiquitously found by high-resolution Atacama Large Millimetre Array observations. Under the hypothesis that they are opened by planets, in this paper we investigate how the minimum planet mass needed to open a gap varies across different stellar host masses and distances from the star. The dependence on the stellar host mass is particularly interesting because, at least in principle, gap opening around low-mass stars should be possible for lower mass planets, giving us a look into the young, low-mass planet population. Using dusty hydrodynamical simulations, we find however the opposite behaviour, as a result of the fact that discs around low-mass stars are geometrically thicker: gap opening around low-mass stars can require more massive planets. Depending on the theoretical isochrone employed to predict the relationship between stellar mass and luminosity, the gap opening planet mass could also be independent of stellar mass, but in no case we find that gap opening becomes easier around low-mass stars. This would lead to the expectation of a lower incidence of such structures in lower mass stars, since exoplanet surveys show that low-mass stars have a lower fraction of giant planets. More generally, our study enables future imaging observations as a function of stellar mass to be interpreted using information on the mass versus luminosity relations of the observed samples.

Testing exoplanet evaporation with multitransiting systems

ABSTRACT The photoevaporation model is one of the leading explanations for the evolution of small, close-in planets and the origin of the radius-valley. However, without planet mass measurements, it is challenging to test the photoevaporation scenario. Even if masses are available for individual planets, the host star’s unknown EUV/X-ray history makes it difficult to assess the role of photoevaporation. We show that systems with multiple transiting planets are the best in which to rigorously test the photoevaporation model. By scaling one planet to another in a multitransiting system, the host star’s uncertain EUV/X-ray history can be negated. By focusing on systems that contain planets that straddle the radius-valley, one can estimate the minimum masses of planets above the radius-valley (and thus are assumed to have retained a voluminous hydrogen/helium envelope). This minimum mass is estimated by assuming that the planet below the radius-valley entirely lost its initial hydrogen/helium envelope, then calculating how massive any planet above the valley needs to be to retain its envelope. We apply this method to 104 planets above the radius gap in 73 systems for which precise enough radii measurements are available. We find excellent agreement with the photoevaporation model. Only two planets (Kepler-100c and 142c) appear to be inconsistent, suggesting they had a different formation history or followed a different evolutionary pathway to the bulk of the population. Our method can be used to identify TESS systems that warrant radial-velocity follow-up to further test the photoevaporation model. The software to estimate minimum planet masses is publicly available at https://github.com/jo276/EvapMass.

The newborn planet population emerging from ring-like structures in discs

ALMA has observed a plethora of ring-like structures in planet forming discs at distances of 10-100 au from their host star. Although several mechanisms have been invoked to explain the origin of such rings, a common explanation is that they trace new-born planets. Under the planetary hypothesis, a natural question is how to reconcile the apparently high frequency of gap-carving planets at 10-100 au with the paucity of Jupiter mass planets observed around main sequence stars at those separations. Here, we provide an analysis of the new-born planet population emerging from observations of gaps in discs, under the assumption that the observed gaps are due to planets. We use a simple estimate of the planet mass based on the gap morphology, and apply it to a sample of gaps recently obtained by us in a survey of Taurus with ALMA. We also include additional data from recent published surveys, thus analysing the largest gap sample to date, for a total of 48 gaps. The properties of the purported planets occupy a distinctively different region of parameter space with respect to the known exo-planet population, currently not accessible through planet finding methods. Thus, no discrepancy in the mass and radius distribution of the two populations can be claimed at this stage. We show that the mass of the inferred planets conforms to the theoretically expected trend for the minimum planet mass needed to carve a dust gap. Finally, we estimate the separation and mass of the putative planets after accounting for migration and accretion, for a range of evolutionary times, finding a good match with the distribution of cold Jupiters.

How much does turbulence change the pebble isolation mass for planet formation?

Context. When a planet becomes massive enough, it gradually carves a partial gap around its orbit in the protoplanetary disk. A pressure maximum can be formed outside the gap where solids that are loosely coupled to the gas, typically in the pebble size range, can be trapped. The minimum planet mass for building such a trap, which is called the pebble isolation mass (PIM), is important for two reasons: it marks the end of planetary growth by pebble accretion, and the trapped dust forms a ring that may be observed with millimetre observations. Aims. We study the effect of disk turbulence on the PIM and find its dependence on the gas turbulent viscosity, aspect ratio, and particles Stokes number. Methods. By means of 2D gas hydrodynamical simulations, we found the minimum planet mass to form a radial pressure maximum beyond the orbit of the planet, which is the necessary condition to trap pebbles. We then carried out 2D gas plus dust hydrodynamical simulations to examine how dust turbulent diffusion impacts particles trapping at the pressure maximum. We finally provide a semi-analytical calculation of the PIM based on comparing the radial drift velocity of solids and the root mean square turbulent velocity fluctuations around the pressure maximum. Results. From our results of gas simulations, we provide an expression for the PIM vs. disk aspect ratio and turbulent viscosity. Our gas plus dust simulations show that the effective PIM can be nearly an order of magnitude larger in high-viscosity disks because turbulence diffuse particles out of the pressure maximum. This is quantified by our semi-analytical calculation, which gives an explicit dependence of the PIM with Stokes number of particles. Conclusions. Disk turbulence can significantly alter the PIM, depending on the level of turbulence in regions of planet formation.

Aeronomical constraints to the minimum mass and maximum radius of hot low-mass planets

Stimulated by the discovery of a number of close-in low-density planets, we generalise the Jeans escape parameter taking hydrodynamic and Roche lobe effects into account. We furthermore define $\Lambda$ as the value of the Jeans escape parameter calculated at the observed planetary radius and mass for the planet's equilibrium temperature and considering atomic hydrogen, independently of the atmospheric temperature profile. We consider 5 and 10 $M_{\oplus}$ planets with an equilibrium temperature of 500 and 1000 K, orbiting early G-, K-, and M-type stars. Assuming a clear atmosphere and by comparing escape rates obtained from the energy-limited formula, which only accounts for the heating induced by the absorption of the high-energy stellar radiation, and from a hydrodynamic atmosphere code, which also accounts for the bolometric heating, we find that planets whose $\Lambda$ is smaller than 15-35 lie in the "boil-off" regime, where the escape is driven by the atmospheric thermal energy and low planetary gravity. We find that the atmosphere of hot (i.e. $T_{\rm eq}\gtrapprox$ 1000 K) low-mass ($M_{\rm pl}\lessapprox$ 5 $M_{\oplus}$) planets with $\Lambda$ < 15-35 shrinks to smaller radii so that their $\Lambda$ evolves to values higher than 15-35, hence out of the boil-off regime, in less than $\approx$500 Myr. Because of their small Roche lobe radius, we find the same result also for hot (i.e. $T_{\rm eq}\gtrapprox$ 1000 K) higher mass ($M_{\rm pl}\lessapprox$ 10 $M_{\oplus}$) planets with $\Lambda$ < 15-35, when they orbit M-dwarfs. For old, hydrogen-dominated planets in this range of parameters, $\Lambda$ should therefore be $\geq$15-35, which provides a strong constraint on the planetary minimum mass and maximum radius and can be used to predict the presence of aerosols and/or constrain planetary masses, for example.

HOW BRIGHT ARE PLANET-INDUCED SPIRAL ARMS IN SCATTERED LIGHT?

ABSTRACT Recently, high angular resolution imaging instruments such as SPHERE and GPI have discovered many spiral-arm-like features in near-infrared scattered-light images of protoplanetary disks. Theory and simulations have suggested that these arms are most likely excited by planets forming in the disks; however, a quantitative relation between the arm-to-disk brightness contrast and planet mass is still missing. Using 3D hydrodynamics and radiative transfer simulations, we examine the morphology and contrast of planet-induced arms in disks. We find a power-law relation for the face-on arm contrast (δ max) as a function of planet mass ( ) and disk aspect ratio (h/r): . With current observational capabilities, at a 30 au separation, the minimum planet mass for driving detectable arms in a disk around a 1 Myr, 1 star at 140 pc at low inclinations is around Saturn mass. For planets more massive than Neptune masses, they typically drive multiple arms. Therefore, in observed disks with spirals, it is unlikely that each spiral arm originates from a different planet. We also find that only massive perturbers with at least multi-Jupiter masses are capable of driving bright arms with as found in SAO 206462, MWC 758, and LkHα 330, and these arms do not follow linear wave propagation theory. Additionally, we find that the morphology and contrast of the primary and secondary arms are largely unaffected by a modest level of viscosity with . Finally, the contrast of the arms in the SAO 206462 disk suggests that the perturber SAO 206462 b at ∼100 au is about in mass.

THE MAGELLAN PFS PLANET SEARCH PROGRAM: RADIAL VELOCITY AND STELLAR ABUNDANCE ANALYSES OF THE 360 au, METAL-POOR BINARY “TWINS” HD 133131A &amp; B*

ABSTRACTWe present a new precision radial velocity (RV) data set that reveals multiple planets orbiting the stars in the ∼360 au, G2+G2 “twin” binary HD 133131AB. Our six years of high-resolution echelle observations from MIKE and five years from the Planet Finder Spectrograph (PFS) on the Magellan telescopes indicate the presence of two eccentric planets around HD 133131A with minimum masses of 1.43 ± 0.03 and 0.63 ± 0.15at 1.44 ± 0.005 and 4.79 ± 0.92 au, respectively. Additional PFS observations of HD 133131B spanning five years indicate the presence of one eccentric planet of minimum mass 2.50 ± 0.05at 6.40 ± 0.59 au, making it one of the longest-period planets detected with RV to date. These planets are the first to be reported primarily based on data taken with the PFS onMagellan, demonstrating the instrument’s precision and the advantage of long-baseline RV observations. We perform a differential analysis between the Sun and each star, and between the stars themselves, to derive stellar parameters and measure a suite of 21 abundances across a wide range of condensation temperatures. The host stars are old (likely ∼9.5 Gyr) and metal-poor ([Fe/H] ∼ −0.30), and we detect a ∼0.03 dex depletion in refractory elements in HD 133131A versus B (with standard errors ∼0.017). This detection and analysis adds to a small but growing sample of binary “twin” exoplanet host stars with precise abundances measured, and represents the most metal-poor and likely oldest in that sample. Overall, the planets around HD 133131A and B fall in an unexpected regime in planet mass–host star metallicity space and will serve as an important benchmark for the study of long-period giant planets.

The unseen planets of double belt debris disc systems

Abstract The gap between two component debris discs is often taken to be carved by intervening planets scattering away the remnant planetesimals. We employ N-body simulations to determine how the time needed to clear the gap depends on the location of the gap and the mass of the planets. We invert this relation, and provide an equation for the minimum planet mass, and another for the expected number of such planets, that must be present to produce an observed gap for a star of a given age. We show how this can be combined with upper limits on the planetary system from direct imaging non-detections (such as with GPI or SPHERE) to produce approximate knowledge of the planetary system.

The minimum mass of detectable planets in protoplanetary discs and the derivation of planetary masses from high-resolution observations.

We investigate the minimum planet mass that produces observable signatures in infrared scattered light and submillimetre (submm) continuum images and demonstrate how these images can be used to measure planet masses to within a factor of about 2. To this end, we perform multi-fluid gas and dust simulations of discs containing low-mass planets, generating simulated observations at 1.65, 10 and 850 μm. We show that the minimum planet mass that produces a detectable signature is ∼15 M⊕: this value is strongly dependent on disc temperature and changes slightly with wavelength (favouring the submm). We also confirm previous results that there is a minimum planet mass of ∼20 M⊕ that produces a pressure maximum in the disc: only planets above this threshold mass generate a dust trap that can eventually create a hole in the submm dust. Below this mass, planets produce annular enhancements in dust outwards of the planet and a reduction in the vicinity of the planet. These features are in steady state and can be understood in terms of variations in the dust radial velocity, imposed by the perturbed gas pressure radial profile, analogous to a traffic jam. We also show how planet masses can be derived from structure in scattered light and submm images. We emphasize that simulations with dust need to be run over thousands of planetary orbits so as to allow the gas profile to achieve a steady state and caution against the estimation of planet masses using gas-only simulations.

Hot Jupiters with relatives: discovery of additional planets in orbit around WASP-41 and WASP-47

We report the discovery of two additional planetary companions to WASP-41 and WASP-47. WASP-41 c is a planet of minimum mass 3.18 $\pm$ 0.20 M$_{\rm Jup}$ and eccentricity 0.29 $\pm$ 0.02, and it orbits in 421 $\pm$ 2 days. WASP-47 c is a planet of minimum mass 1.24 $\pm$ 0.22 M$_{\rm Jup}$ and eccentricity 0.13 $\pm$ 0.10, and it orbits in 572 $\pm$ 7 days. Unlike most of the planetary systems that include a hot Jupiter, these two systems with a hot Jupiter have a long-period planet located at only $\sim$1 au from their host star. WASP-41 is a rather young star known to be chromospherically active. To differentiate its magnetic cycle from the radial velocity effect induced by the second planet, we used the emission in the H$\alpha$ line and find this indicator well suited to detecting the stellar activity pattern and the magnetic cycle. The analysis of the Rossiter-McLaughlin effect induced by WASP-41 b suggests that the planet could be misaligned, though an aligned orbit cannot be excluded. WASP-47 has recently been found to host two additional transiting super Earths. With such an unprecedented architecture, the WASP-47 system will be very important for understanding planetary migration.

THREE PLANETS ORBITING WOLF 1061

ABSTRACT We use archival HARPS spectra to detect three planets orbiting the M3 dwarf Wolf 1061 (GJ 628). We detect a 1.36 M ⊕ minimum-mass planet with an orbital period P = 4.888 days (Wolf 1061b), a 4.25 M ⊕ minimum-mass planet with orbital period P = 17.867 days (Wolf 1061c), and a likely 5.21 M ⊕ minimum-mass planet with orbital period P = 67.274 days (Wolf 1061d). All of the planets are of sufficiently low mass that they may be rocky in nature. The 17.867 day planet falls within the habitable zone for Wolf 1061 and the 67.274 day planet falls just outside the outer boundary of the habitable zone. There are no signs of activity observed in the bisector spans, cross-correlation FWHMs, calcium H &amp; K indices, NaD indices, or Hα indices near the planetary periods. We use custom methods to generate a cross-correlation template tailored to the star. The resulting velocities do not suffer the strong annual variation observed in the HARPS DRS velocities. This differential technique should deliver better exploitation of the archival HARPS data for the detection of planets at extremely low amplitudes.

Future Direct Spectroscopic Detection of Hot Jupiters with IGRINS

ABSTRACTWith about 700 confirmed extrasolar planets, it is time to move beyond discovery and towards characterization. Perhaps the most basic parameter of an extrasolar planet is its mass; however, this is very difficult to determine if the planet does not transit the star. The radial velocity technique, still the most fruitful method of discovering planets in the solar neighborhood, can only determine a minimum planet mass. We investigate a method using the near-future IGRINS near infrared spectrograph to detect the orbital motion of the planet itself. We simulate several observations of a star with an orbiting planet, and search for the spectral signature of the planet by cross-correlating against planet model spectra. A detection appears as a strong peak in the cross-correlation function, and gives the radial velocity of the planet at the time of observation. This, combined with the motion of the star from traditional radial velocity planet search programs, can determine the actual planet mass. We find that the IGRINS instrument can detect the spectral signature from large planets on very close orbits (so-called Hot Jupiters), and that the detections can provide tight constraints on the true planet mass.

BD+15 2940 AND HD 233604: TWO GIANTS WITH PLANETS CLOSE TO THE ENGULFMENT ZONE

We report the discovery of planetary-mass companions to two red giants by the ongoing Penn State - Torun Planet Search (PTPS) conducted with the 9.2-m Hobby-Eberly Telescope. The 1.1 Ms K0-giant, BD+15 2940, has a 1.1 Mj minimum mass companion orbiting the star at a 137.5-day period in a 0.54 AU orbit what makes it the closest - in planet around a giant and possible subject of engulfment as the consequence of stellar evolution. HD 233604, a 1.5 Ms K5-giant, is orbited by a 6.6 Mj minimum mass planet which has a period of 192 days and a semi-major axis of only 0.75 AU making it one of the least distant planets to a giant star. The chemical composition analysis of HD 233604 reveals a relatively high 7Li abundance which may be a sign of its early evolutionary stage or recent engulfment of another planet in the system. We also present independent detections of planetary-mass companions to HD 209458 and HD 88133, and stellar activity-induced RV variations in HD 166435, as part of the discussion of the observing and data analysis methods used in the PTPS project.

PLANETS AROUND THE K-GIANTS BD+20 274 AND HD 219415

We present the discovery of planet-mass companions to two giant stars by the ongoing Penn State- Toru\'n Planet Search (PTPS) conducted with the 9.2 m Hobby-Eberly Telescope. The less massive of these stars, K5-giant BD+20 274, has a 4.2 MJ minimum mass planet orbiting the star at a 578-day period and a more distant, likely stellar-mass companion. The best currently available model of the planet orbiting the K0-giant HD 219415 points to a Jupiter-mass companion in a 5.7-year, eccentric orbit around the star, making it the longest period planet yet detected by our survey. This planet has an amplitude of \sim18 m/s, comparable to the median radial velocity (RV) "jitter", typical of giant stars.

GJ 581 update: Additional evidence for a Super‐Earth in the habitable zone

AbstractWe present an analysis of the significantly expanded HARPS 2011 radial velocity data set for GJ 581 that was presented by Forveille et al. (2011). Our analysis reaches substantially different conclusions regarding the evidence for a Super‐Earth‐mass planet in the star's Habitable Zone. We were able to reproduce their reported χ2ν and RMS values only after removing some outliers from their models and refitting the trimmed down RV set. A suite of 4000 N‐body simulations of their Keplerian model all resulted in unstable systems and revealed that their reported 3.6σ detection of e = 0.32 for the eccentricity of GJ 581e is manifestly incompatible with the system's dynamical stability. Furthermore, their Keplerian model, when integrated only over the time baseline of the observations, significantly increases the χ2ν and demonstrates the need for including non‐Keplerian orbital precession when modeling this system. We find that a four‐planet model with all of the planets on circular or nearly circular orbits provides both an excellent self‐consistent fit to their RV data and also results in a very stable configuration. The periodogram of the residuals to a 4‐planet all‐circular‐orbit model reveals significant peaks that suggest one or more additional planets in this system. We conclude that the present 240‐point HARPS data set, when analyzed in its entirety, and modeled with fully self‐consistent stable orbits, by and of itself does offer significant support for a fifth signal in the data with a period near 32 days. This signal has a false alarm probability of &lt;4% and is consistent with a planet of minimum mass 2.2 M⊕, orbiting squarely in the star's habitable zone at 0.13 AU, where liquid water on planetary surfaces is a distinct possibility (© 2012 WILEY‐VCH Verlag GmbH &amp; Co. KGaA, Weinheim)