ABSTRACT
We report the discovery of two transiting planets orbiting K2-290 (EPIC 249624646), a bright (V = 11.11) late F-type star residing in a triple-star system. It was observed during Campaign 15 ...of the K2 mission, and in order to confirm and characterize the system, follow-up spectroscopy and AO imaging were carried out using the FIES, HARPS, HARPS-N, and IRCS instruments. From AO imaging and Gaia data we identify two M-dwarf companions at a separation of 113 ± 2 and $2467_{-155}^{+177}$ au. From radial velocities, K2 photometry, and stellar characterization of the host star, we find the inner planet to be a mini-Neptune with a radius of 3.06 ± 0.16 R⊕ and an orbital period of P = 9.2 d. The radius of the mini-Neptune suggests that the planet is located above the radius valley, and with an incident flux of F ∼ 400 F⊕, it lies safely outside the super-Earth desert. The outer warm Jupiter has a mass of 0.774 ± 0.047 MJ and a radius of 1.006 ± 0.050 RJ, and orbits the host star every 48.4 d on an orbit with an eccentricity e < 0.241. Its mild eccentricity and mini-Neptune sibling suggest that the warm Jupiter originates from in situ formation or disc migration.
ZnTe thin films were deposited on SiO2 substrate by pulsed-laser deposition (PLD) at room temperature. The ZnTe films were immersed in different concentrations of Cu(NO3)2–3H2O solutions for 1min, ...then heated at 200 and 300°C, both temperatures for 10min in a N2 atmosphere. The X-ray diffraction (XRD) showed the hexagonal and orthorhombic ZnTe phases when the copper-doped films were heated at 200 and 300°C for 10min respectively. The films immersed in 15 and 60mg of Cu(NO3)2–H2O solutions had similar values of sheet resistance ~104Ω/□, resistivity ~10−1Ωcm, specific contact resistance ~10−4Ωcm2, and hall mobility 5cm2/Vs. Also, the copper-doped conditions were used to dope the source and drain bias to make a thin-film transistor of ZnTe (TFT) by photolithography.
ZnTe TFT by photolithography. Variation of the (a) sheet resistance and (b) resistivity, when the mg of Cu(NO3)2–3H2O is increased. Display omitted
•The sheet resistance of the undoped ZnTe decreased from 2.52×1010 to 3.92×104Ω/□ when the films were immersed in 15mg of Cu(NO3)2–3H2O solution.•The resistivity of the undoped ZnTe decreased from 2.26×105 to 3.50×10−1Ωcm when the films were immersed in 15mg of Cu(NO3)2–3H2O solution.•The p-type ZnTe thin films doped with 15 and 60mg of Cu(NO3)2–H2O solutions had similar values of sheet resistance, resistivity, specific contact resistance, and hall mobility.•The X-ray diffraction (XRD) showed the hexagonal and orthorhombic ZnTe phases.•The hole mobility of the ZnTe TFT immersed in 15mg of Cu(NO3)2–H2O solution was 1×10−2cm2/Vs.
Planets with orbital periods shorter than 1 day are rare and have formation histories that are not completely understood. Small ( R p < 2 R ⊕ ) ultra-short-period (USP) planets are highly irradiated, ...probably have rocky compositions with high bulk densities, and are often found in multi-planet systems. Additionally, USP planets found around small stars are excellent candidates for characterization using present-day instrumentation. Of the current full sample of approximately 5500 confirmed exoplanets, only 130 are USP planets and around 40 have mass and radius measurements. Wolf 327 (TOI-5747) is an M dwarf ( R * = 0.406 ± 0.015 R ⊙ , M * = 0.405 ± 0.019 M ⊙ , T eff = 3542 ± 70 K, and V = 13 mag) located at a distance d = 28.5 pc. NASA’s planet hunter satellite, TESS, detected transits in this star with a period of 0.573 day (13.7 h) and with a transit depth of 818 ppm. Ground-based follow-up photometry, high resolution imaging, and radial velocity (RV) measurements taken with the CARMENES spectrograph confirm the presence of this new USP planet. Wolf 327b is a super-Earth with a radius of R p = 1.24 ± 0.06 R ⊕ and a mass of M p = 2.53 ± 0.46 M ⊕ , yielding a bulk density of 7.24 ± 1.66 g cm −3 and thus suggesting a rocky composition. Owing to its close proximity to its host star ( a = 0.01 au), Wolf 327b has an equilibrium temperature of 996 ± 22 K. This planet has a mass and radius similar to K2-229b, a planet with an inferred Mercury-like internal composition. Planet interior models suggest that Wolf 327b has a large iron core, a small rocky mantle, and a negligible (if any) H/He atmosphere.
ZnS thin films have been deposited on glass and SiO2 substrates in an alkaline solution using the chemical bath deposition method. The reaction solution is prepared using zinc acetate, thiourea, ...tri-ethanolamine and tri-sodium citrate at pH close to 10.0. Different deposition times 30, 60 and 90min, were selected to study the performance of ZnS thin films. According to the results, the surface morphology was affected by the type of substrate, showing different rates of growth for each one of them. The growth of ZnS on glass was more homogeneous for the material at 90min of reaction showing a high transmission, >80% in the spectra range from 300nm to 800nm, and the optical band gap of the sample was about 3.62eV.
Display omitted
•ZnS films were deposited by CBD method with different substrates.•The thickness of the film increases in the 10–60nm range.•ZnS showed optical transmission of about 80% and band gap of 3.67eV.•The electrical resistivity of ZnS thin films was over 106Ωcm.
Context.
The number of super-Earth and Earth-mass planet discoveries has increased significantly in the last two decades thanks to the Doppler radial velocity and planetary transit observing ...techniques. Either technique can detect planet candidates on its own, but the power of a combined photometric and spectroscopic analysis is unique for an insightful characterization of the planets, which in turn has repercussions for our understanding of the architecture of planetary systems and, therefore, their formation and evolution.
Aims.
Two transiting planet candidates with super-Earth radii around the nearby (
d
= 70.64 ± 0.06 pc) K7–M0 dwarf star TOI-1238 were announced by NASA’s Transiting Exoplanet Survey Satellite (TESS), which observed the field of TOI-1238 in four different sectors. We aim to validate their planetary nature using precise radial velocities taken with the CARMENES spectrograph.
Methods.
We obtained 55 CARMENES radial velocity measurements that span the 11 months between 9 May 2020 and 5 April 2021. For a better characterization of the parent star’s activity, we also collected contemporaneous optical photometric observations at the Joan Oró and Sierra Nevada observatories and retrieved archival photometry from the literature. We performed a combined TESS+CARMENES photometric and spectroscopic analysis by including Gaussian processes and Keplerian orbits to account for the stellar activity and planetary signals simultaneously.
Results.
We estimate that TOI-1238 has a rotation period of 40 ± 5 d based on photometric and spectroscopic data. The combined analysis confirms the discovery of two transiting planets, TOI-1238 b and c, with orbital periods of 0.764597
−0.000011
+0.000013
d and 3.294736
−0.000036
+0.000034
d, masses of 3.76
−1.07
+1.15
M
⊕
and 8.32
−1.88
+1.90
M
⊕
, and radii of 1.21
−0.10
+0.11
R
⊕
and 2.11
−0.14
+0.14
R
⊕
. They orbit their parent star at semimajor axes of 0.0137 ± 0.0004 au and 0.036 ± 0.001 au, respectively.The two planets are placed on opposite sides of the radius valley for M dwarfs and lie between the star and the inner border of TOI-1238’s habitable zone. The inner super-Earth TOI-1238 b is one of the densest ultra-short-period planets ever discovered (
ρ
= 11.7
−3.4
+4.2
g cm
−3
). The CARMENES data also reveal the presence of an outer, non-transiting, more massive companion with an orbital period and radial velocity amplitude of ≥600 d and ≥70 m s
−1
, which implies a likely mass of
M
≥ 2 √(1−
e
2
)
M
Jup
and a separation ≥1.1 au from its parent star.
Context. Multiplanet systems are excellent laboratories to test planet formation models as all planets are formed under the same initial conditions. In this context, systems transiting bright stars ...can play a key role, since planetary masses, radii, and bulk densities can be measured. Aims. GJ 9827 (K2-135) has recently been found to host a tightly packed system consisting of three transiting small planets whose orbital periods of 1.2, 3.6, and 6.2 days are near the 1:3:5 ratio. GJ 9827 hosts the nearest planetary system (~30 pc) detected by NASA’s Kepler or K2 space mission. Its brightness (V = 10.35 mag) makes the star an ideal target for detailed studies of the properties of its planets. Methods. Combining the K2 photometry with high-precision radial-velocity measurements gathered with the FIES, HARPS, and HARPS-N spectrographs we revised the system parameters and derive the masses of the three planets. Results. We find that GJ 9827 b has a mass of Mb = 3.69−0.46+0.48 M⊕ $M_{\mathrm{b}}\,{=}\,3.69 _{ - 0.46 } ^ { + 0.48 }\, M_{\oplus}$ Mb = 3.69−0.46+0.48 M⊕ and a radius of Rb = 1.58−0.13+0.14 R⊕ $R_{\mathrm{b}}=\,1.58 _{ - 0.13 } ^ { + 0.14 }\,R_{\oplus}$Rb= 1.58−0.13+0.14 R⊕, yielding a mean density of ρb = 5.11−1.27+1.74 g cm−3 $\rho_{\mathrm{b}}=\,5.11_{ - 1.27 }^{ + 1.74}\,\textrm{g\,cm}^{-3}$ρb= 5.11−1.27+1.74 g cm−3. GJ 9827 c has a mass of Mc = 1.45−0.57+0.58 M⊕ $M_{\mathrm{c}}=\,1.45 _{ - 0.57 } ^ { + 0.58 }\,M_{\oplus}$Mc= 1.45−0.57+0.58 M⊕, radius of Rc = 1.24−0.11+0.11 R⊕ $R_{\mathrm{c}}=\,1.24 _{ - 0.11 } ^ { + 0.11 }\,R_{\oplus}$Rc= 1.24−0.11+0.11 R⊕, and a mean density of ρc = 4.13−1.77+2.31 g cm−3 $\rho_{\mathrm{c}}\,{=}\,4.13 _{ - 1.77 } ^ { + 2.31 }\,\textrm{g\,cm}^{-3}$ρc = 4.13−1.77+2.31 g cm−3. For GJ 9827 d, we derive Md = 1.45−0.57+0.58 M⊕ $M_{\mathrm{d}}\,{=}\,1.45 _{ - 0.57 } ^ { + 0.58 }\,M_{\oplus}$Md = 1.45−0.57+0.58 M⊕, Rd = 1.24−0.11+0.11 R⊕ $R_{\mathrm{d}}\,{=}\,1.24 _{ - 0.11 } ^ { + 0.11 }\,R_{\oplus}$Rd = 1.24−0.11+0.11 R⊕, and ρd = 1.51−0.53+0.71 g cm−3 $\rho_{\mathrm{d}}\,{=}\,1.51 _{ - 0.53 } ^ { + 0.71 }\,\textrm{g\,cm}^{-3}$ρd = 1.51−0.53+0.71 g cm−3. Conclusions. GJ 9827 is one of the few known transiting planetary systems for which the masses of all planets have been determined with a precision better than 30%. This system is particularly interesting because all three planets are close to the limit between super-Earths and sub-Neptunes. The planetary bulk compositions are compatible with a scenario where all three planets formed with similar core and atmosphere compositions, and we speculate that while GJ 9827 b and GJ 9827 c lost their atmospheric envelopes, GJ 9827 d maintained its primordial atmosphere, owing to the much lower stellarirradiation. This makes GJ 9827 one of the very few systems where the dynamical evolution and the atmosphericescape can be studied in detail for all planets, helping us to understand how compact systems form and evolve.
Context. The Kepler extended mission, also known as K2, has provided the community with a wealth of planetary candidates that orbit stars typically much brighter than the targets of the original ...mission. These planet candidates are suitable for further spectroscopic follow-up and precise mass determinations, leading ultimately to the construction of empirical mass-radius diagrams. Particularly interesting is to constrain the properties of planets that are between Earth and Neptune in size, the most abundant type of planet orbiting Sun-like stars with periods of less than a few years. Aims. Among many other K2 candidates, we discovered a multi-planetary system around EPIC 246471491, referred to henceforth as K2-285, which contains four planets, ranging in size from twice the size of Earth to nearly the size of Neptune. We aim here at confirming their planetary nature and characterizing the properties of this system. Methods. We measure the mass of the planets of the K2-285 system by means of precise radial-velocity measurements using the CARMENES spectrograph and the HARPS-N spectrograph. Results. With our data we are able to determine the mass of the two inner planets of the system with a precision better than 15%, and place upper limits on the masses of the two outer planets. Conclusions. We find that K2-285b has a mass of Mb = 9.68−1.37+1.21 $9.68 _{ - 1.37 } ^ { + 1.21 } $ 9.68−1.37+1.21 M⊕ and a radius of Rb = 2.59−0.06+0.06 R⊕ $2.59 _{ - 0.06 } ^ { + 0.06 }\,R_{\oplus}$2.59−0.06+0.06 R⊕ , yielding a mean density of ρb = 3.07−0.45+0.45 g cm−3 $\rho_{\mathrm{b}}{\,=\,}3.07_{-0.45}^{+0.45}\,\textrm{g}\,\textrm{cm}^{-3}$ρb = 3.07−0.45+0.45 g cm−3 , while K2-285c has a mass of Mc = 15.68−2.13+2.28 M⊕ $15.68 _{ - 2.13 } ^ { + 2.28 }\,M_{\oplus}$15.68−2.13+2.28 M⊕ , radius of Rc = 3.53−0.08+0.08 R⊕ $3.53 _{ - 0.08 } ^ { + 0.08 }\,R_{\oplus}$3.53−0.08+0.08 R⊕ , and a mean density of ρc = 1.95−0.28+0.32 g cm−3 $\rho_{\mathrm{c}}{\,=\,}1.95_{-0.28}^{+0.32}\,\textrm{g}\,\textrm{cm}^{-3}$ρc = 1.95−0.28+0.32 g cm−3 . For K2-285d (Rd = 2.48−0.06+0.06 R⊕ $2.48 _{ - 0.06 } ^ { + 0.06 }\,R_{\oplus}$2.48−0.06+0.06 R⊕ ) and K2-285e (Re = 1.95−0.05+0.05 R⊕ $1.95 _{ - 0.05 } ^ { + 0.05 }\,R_{\oplus}$1.95−0.05+0.05 R⊕ ), the upper limits for the masses are 6.5 M⊕ and 10.7 M⊕, respectively. The system is thus composed of an (almost) Neptune-twin planet (in mass and radius), two sub-Neptunes with very different densities and presumably bulk composition, and a fourth planet in the outermost orbit that resides right in the middle of the super-Earth/sub-Neptune radius gap. Future comparative planetology studies of this system would provide useful insights into planetary formation, and also a good test of atmospheric escape and evolution theories.
To compare the bleaching efficacy and tooth sensitivity (TS) of two hydrogen peroxide (HP) concentrations (20% and 35%) used for in-office bleaching associated or not with a light-emitting diode ...(LED)/laser light activation.
Seventy-seven patients with a right maxillary canine darker than A3 were selected for this single-blind randomized trial. The participants were distributed in four groups: bleaching with 35% HP, 35% HP + LED/laser, 20% HP, and 20% HP + LED/laser. The anterior teeth were bleached in two sessions, using a 35% or 20% HP gel with a one-week interval. Each session had three applications of 15 minutes. For the light-activated groups, the LED/laser energy (Whitening Laser Light Plus, DMC) was employed according to the manufacturer's instructions. The color change was evaluated by subjective and objective methods. Participants recorded TS with five-point verbal and visual analog scales. Color change in ΔE was evaluated by analysis of variance and Tukey tests (α=0.05) and in ΔSGU with Kruskall-Wallis and Dunn test. The absolute risk of TS and TS intensity were evaluated by Fisher exact test and Kruskall-Wallis test, respectively (α=0.05).
All groups achieved the same level of whitening, except for the 20% HP group, which showed the lowest degree of whitening in the subjective analysis. The use of light did not increase the absolute risk or intensity of TS. No significant difference among groups was observed when color changes were assessed with the spectrophotometer.
According to the value-oriented shade guide, the use of LED/laser light activation was able to increase the degree of whitening of the 20% HP group, but this association was not useful for the 35% HP gel. The spectrophotometer, however, did not detect significant differences among groups.
Context.
Despite being a prominent subset of the exoplanet population discovered in the past three decades, the nature and provenance of sub-Neptune-sized planets is still one of the open questions ...in exoplanet science.
Aims.
For planets orbiting bright stars, precisely measuring the orbital and planet parameters of the system is the best approach to distinguish between competing theories regarding their formation and evolution.
Methods.
We obtained 69 new radial velocity observations of the mid-M dwarf G 9–40 with the CARMENES instrument to measure for the first time the mass of its transiting sub-Neptune planet, G 9–40 b, discovered in data from the K2 mission.
Results.
Combined with new observations from the TESS mission during Sectors 44, 45, and 46, we are able to measure the radius of the planet to an uncertainty of 3.4% (
R
b
= 1.900 ± 0.065
R
⊕
) and determine its mass with a precision of 16% (
M
b
= 4.00 ± 0.63
M
⊕
). The resulting bulk density of the planet is inconsistent with a terrestrial composition and suggests the presence of either a water-rich core or a significant hydrogen-rich envelope.
Conclusions.
G 9–40 b is referred to as a keystone planet due to its location in period-radius space within the radius valley. Several theories offer explanations for the origin and properties of this population and this planet is a valuable target for testing the dependence of those models on stellar host mass. By virtue of its brightness and small size of the host, it joins L 98-59 d as one of the two best warm (
T
eq
~ 400 K) sub-Neptunes for atmospheric characterization with JWST, which will probe cloud formation in sub-Neptune-sized planets and break the degeneracies of internal composition models.
This work focuses on the study of zinc sulfide (ZnS) thin films prepared by chemical bath deposition. The effect of the pH ranging from 10.0 to 10.75 on quality of ZnS thin films on SiO2 substrate is ...investigated. The effect of pH on the surface showed that the variation of pH has a significant effect on the morphology of the ZnS thin films. The sample with pH value of 10.50 was uniform, free of agglomerates with band gap energy about 3.67eV. The resistivity of ZnS thin films on SiO2 substrate with different pH value were about 107Ωcm.
Display omitted
•ZnS films were deposited at different pH value in order to study the surface.•The variation of pH has a significant effect on the morphology of the ZnS film.•ZnS films indicates a good transmission in the spectra range from 350 to 800nm.•The resistivity values may be due to the presence of some cracks in the film surface.
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