Highly irradiated planets in the hot Neptune desert are usually either small (R < 2 Rearth) and rocky or they are gas giants with radii of >1 Rjup. Here, we report on the intermediate-sized planet ...TOI-2196 on a 1.2 day orbit around a G-type star discovered by TESS in sector 27. We collected 42 radial velocity measurements with the HARPS spectrograph to determine the mass. The radius of TOI-2196 b is 3.51 +/- 0.15 Rearth, which, combined with the mass of 26.0 +/- 1.3 Mearth, results in a bulk density of 3.31+0.51-0.43 g/cm3. Hence, the radius implies that this planet is a sub-Neptune, although the density is twice than that of Neptune. A significant trend in the HARPS radial velocities points to the presence of a distant companion with a lower limit on the period and mass of 220 days and 0.65 Mjup, respectively, assuming zero eccentricity. The short period of planet b implies a high equilibrium temperature of 1860 +/- 20 K, for zero albedo and isotropic emission. This places the planet in the hot Neptune desert, joining a group of very few planets in this parameter space discovered in recent years. These planets suggest that the hot Neptune desert may be divided in two parts for planets with equilibrium temperatures of > 1800 K: a hot sub-Neptune desert devoid of planets with radii of 1.8-3 Rearth and a sub-Jovian desert for radii of 5-12 Rearth. More planets in this parameter space are needed to further investigate this finding. Planetary interior structure models of TOI-2196 b are consistent with a H/He atmosphere mass fraction between 0.4 % and 3 %, with a mean value of 0.7 % on top of a rocky interior. We estimated the amount of mass this planet might have lost at a young age, and we find that while the mass loss could have been significant, the planet had not changed in terms of character: it was born as a small volatile-rich planet, and it remains one at present.
We present the confirmation and characterization of three hot Jupiters, TOI-1181b, TOI-1516b, and TOI-2046b, discovered by the TESS space mission. The reported hot Jupiters have orbital periods ...between 1.4 and 2.05 days. The masses of the three planets are \(1.18\pm0.14\) M\(_{\mathrm{J}}\), \(3.16\pm0.12\)\, M\(_{\mathrm{J}}\), and 2.30 \(\pm 0.28\) M\(_{\mathrm{J}}\), for TOI-1181b, TOI-1516b, and TOI-2046b, respectively. The stellar host of TOI-1181b is a F9IV star, whereas TOI-1516b and TOI-2046b orbit F main sequence host stars. The ages of the first two systems are in the range of 2-5 Gyrs. However, TOI-2046 is among the few youngest known planetary systems hosting a hot Jupiter, with an age estimate of 100-400 Myrs. The main instruments used for the radial velocity follow-up of these three planets are located at Ondřejov, Tautenburg and McDonald Observatory, and all three are mounted on 2-3 meter aperture telescopes, demonstrating that mid-aperture telescope networks can play a substantial role in the follow-up of gas giants discovered by \textit{TESS} and in the future by \textit{PLATO}.
We report the discovery of two transiting planets around the bright (\(V=9.9\) mag) main sequence F7 star TOI-1670 by the Transiting Exoplanet Survey Satellite. TOI-1670 b is a sub-Neptune ...(\(R_\mathrm{b} = 2.06_{-0.15}^{+0.19}\) \(R_\oplus\)) on a 10.9-day orbit and TOI-1670 c is a warm Jupiter (\(R_\mathrm{c} = 0.987_{-0.025}^{+0.025}\) \(R_\mathrm{Jup}\)) on a 40.7-day orbit. Using radial velocity observations gathered with the Tull coudé Spectrograph on the Harlan J. Smith telescope and HARPS-N on the Telescopio Nazionale Galileo, we find a planet mass of \(M_\mathrm{c} = 0.63_{-0.08}^{+0.09}\) \(M_\mathrm{Jup}\) for the outer warm Jupiter, implying a mean density of \(\rho_c = 0.81_{-0.11}^{+0.13}\) g cm\(^{-3}\). The inner sub-Neptune is undetected in our radial velocity data (\(M_\mathrm{b} < 0.13\) \(M_\mathrm{Jup}\) at the 99% confidence level). Multi-planet systems like TOI-1670 hosting an outer warm Jupiter on a nearly circular orbit (\(e_\mathrm{c} = 0.09_{-0.04}^{+0.05}\)) and one or more inner coplanar planets are more consistent with "gentle" formation mechanisms such as disk migration or \(in\) \(situ\) formation rather than high-eccentricity migration. Of the 11 known systems with a warm Jupiter and a smaller inner companion, 8 (73%) are near a low-order mean-motion resonance, which can be a signature of migration. TOI-1670 joins two other systems (27% of this subsample) with period commensurabilities greater than 3, a common feature of \(in\) \(situ\) formation or halted inward migration. TOI-1670 and the handful of similar systems support a diversity of formation pathways for warm Jupiters.
We report the discovery of a warm Neptune and a hot sub-Neptune transiting TOI-421 (BD-14 1137, TIC 94986319), a bright (V=9.9) G9 dwarf star in a visual binary system observed by the TESS space ...mission in Sectors 5 and 6. We performed ground-based follow-up observations -- comprised of LCOGT transit photometry, NIRC2 adaptive optics imaging, and FIES, CORALIE, HARPS, HIRES, and PFS high-precision Doppler measurements -- and confirmed the planetary nature of the 16-day transiting candidate announced by the TESS team. We discovered an additional radial velocity signal with a period of 5 days induced by the presence of a second planet in the system, which we also found to transit its host star. We found that the inner mini-Neptune, TOI-421b, has an orbital period of Pb =5.19672 +- 0.00049 days, a mass of Mb = 7.17 +- 0.66 Mearth and a radius of Rb = 2.68+0.19-0.18 Rearth, whereas the outer warm Neptune, TOI-421 c, has a period of Pc =16.06819 +- 0.00035 days, a mass of Mc = 16.42+1.06-1.04 Mearth, a radius of Rc = 5.09+0.16-0.15 Rearth and a density of rho_c =0.685+0.080-0.072 g cm-3 . With its characteristics the inner planet (rho_b=2.05+0.52-0.41 g cm-3) is placed in the intriguing class of the super-puffy mini-Neptunes. TOI-421b and TOI-421c are found to be well suitable for atmospheric characterization. Our atmospheric simulations predict significant Ly-alpha transit absorption, due to strong hydrogen escape in both planets, and the presence of detectable CH_4 in the atmosphere of TOI-421c if equilibrium chemistry is assumed.
Thousands of transiting exoplanets have been discovered to date, thanks in great part to the {\em Kepler} space mission. As in all populations, and certainly in the case of exoplanets, one finds ...unique objects with distinct characteristics. Here we will describe the properties and behaviour of a small group of `disintegrating' exoplanets discovered over the last few years (KIC 12557548b, K2-22b, and others). They evaporate, lose mass unraveling their naked cores, produce spectacular dusty comet-like tails, and feature highly variable asymmetric transits. Apart from these exoplanets, there is observational evidence for even smaller `exo-'objects orbiting other stars: exoasteroids and exocomets. Most probably, such objects are also behind the mystery of Boyajian's star. Ongoing and upcoming space missions such as {\em TESS} and PLATO will hopefully discover more objects of this kind, and a new era of the exploration of small extrasolar systems bodies will be upon us.
In this article, we detail the strategic partnerships "Per Aspera Ad Astra Simul" and "European Collaborating Astronomers Project: Espana-Czechia-Slovakia", and the educational activities that have ...been carried out as part of these grants. This highlights the potential of Key Action 2 of the ERASMUS+ programme to support projects international educational projects, as well as the great impact that such projects can have on the general public and on the continued development of early career researchers.
In this article, we detail the strategic partnerships "Per Aspera Ad Astra Simul" and "European Collaborating Astronomers Project: España-Czechia-Slovakia". These strategic partnerships were ...conceived to foment international collaboration for educational activities (aimed at all levels) as well as to support the development and growth of early career researchers. The activities, carried out under the auspices of these strategic partnerships, demonstrate that Key Action 2 of the Erasmus+ programme can be an extremely valuable resource for supporting international educational projects, as well as the great impact that such projects can have on the general public and on the continued development of early career researchers. We strongly encourage other educators to make use of the opportunities offered by the Erasmus+ scheme.
Petr Kabáth, Vladimír Karas, Ernst Paunzen.
This year´s summer school, held in Brno in September 1-11, 2015 attended by advanced MSc´s, PhD students, Postdocs and senior astronomers presented modern ...instruments available for observations in the Optical and IR domains, together with their scientific tasks and performances. Primarily, the ESO instruments (ESO - European Organization for Astronomical Research in the Southern Hemisphere), as well as those available through the Opticon Access Program were features.
