Search

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 Transiting Exoplanet Survey Satellite (TESS) space mission in Sectors 5 and 6. We performed ground-based follow-up observations—comprised of Las Cumbres Observatory Global Telescope transit photometry, NIRC2 adaptive optics imaging, and FIbre-fed Echellé Spectrograph, CORALIE, High Accuracy Radial velocity Planet Searcher, High Resolution Échelle Spectrometer, and Planet Finder Spectrograph 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 five 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-421 b, has an orbital period of Pb = 5.19672 ± 0.00049 days, a mass of Mb = 7.17 ± 0.66 M⊕, and a radius of Rb = ${2.68}_{-0.18}^{+0.19}$ R⊕, whereas the outer warm Neptune, TOI-421 c, has a period of Pc = 16.06819 ± 0.00035 days, a mass of Mc = ${16.42}_{-1.04}^{+1.06}$ M⊕, a radius of Rc = ${5.09}_{-0.15}^{+0.16}$ R⊕, and a density of ρc = ${0.685}_{-0.072}^{+0.080}$ g cm-3. With its characteristics, the outer planet (ρc = ${0.685}_{-0.072}^{+0.080}$ g cm-3) is placed in the intriguing class of the super-puffy mini-Neptunes. TOI-421 b and TOI-421 c are found to be well-suited for atmospheric characterization. Our atmospheric simulations predict significant Lyα transit absorption, due to strong hydrogen escape in both planets, as well as the presence of detectable CH4 in the atmosphere of TOI-421 c if equilibrium chemistry is assumed. * Based on observations made with ESO Telescopes at the La Silla Observatory under programs ID 1102.C-0923, 0103.C-0874, 0103.C-0759, 0103.C-0442, and 60.A-970. Based on observations obtained with the Nordic Optical Telescope (NOT), operated on the island of La Palma jointly by Denmark, Finland, Iceland, Norway, and Sweden, in the Spanish Observatorio del Roque de los Muchachos (ORM) of the Instituto de Astrofísica de Canarias (IAC). This paper includes data gathered with the 6.5 m Magellan Telescopes located at Las Campanas Observatory, Chile. This work makes use of observations from the LCOGT network.

The GAPS (Global Architecture of Planetary Systems) project is a, mainly Italian, effort for the comprehensive characterization of the architectural properties of planetary systems as a function of the host stars' characteristics by using radial velocities technique. Since the beginning (2012) the project exploited the HARPS-N high resolution optical spectrograph mounted at the 4-m class TNG telescope in La Palma (Canary Islands). More recently, with the upgrade of the TNG near-infrared spectrograph GIANO-B, obtained in the framework of the GIARPS project, it has become possible to perform simultaneous observations with these two instruments, providing thus, at the same time, data both in the optical and in the near-infrared range. The large amount of data obtained in about 5 years of observations provided various scientific outputs, and among them, time series of radial velocity (RV) profiles of the investigated stellar systems. This contribution shows the first steps undertaken to deploy the GAPS Time Series as an interoperable resource within the VO framework designed by the IVOA. This effort has thus a double goal. On one side there's the aim at making the time series data (from RV up to their originating spectra) available to the general astrophysical community in an interoperable way. On the other side, to provide use cases and a prototyping base to the ongoing time domain priority effort at the IVOA level. Time series dataset discovery, depicted through use cases and mapped against the ObsCore model will be shown, highlighting commonalities as well as missing metadata requirements. Future development steps and criticalities, related also to the joint discovery and access of datasets provided by both the spectrographs operated side by side, will be summarized., Comment: ADASS XXVII Proceedings, poster contribution

After the discovery of V391 Peg b, the first planet detected around a post Red Giant phase star (Silvotti et al. 2007), the EXOTIME (EXOplanet search with the TIming MEthod) project is focused on the search for new planets with similar characteristics. The aim of the project is to organize a global observing network to collect as much data as possible for a sample of five subdwarf B (sdB) stars and share them in order to obtain a more precise analysis. These evolved pulsators may have extremely regular oscillation periods. This feature makes these stars suitable to search for planetary companions with the timing method as in the case of pulsars. In this contribution we present the project and some preliminary results for the star PG 1325+101 (QQ Vir) after the first two years of activity., Comment: Proceedings of the 4th HELAS Conference (Lanzarote, 1-5 Feb. 2010), Astron. Nachrichten, in press