We present the discovery and characterization of HIP 33609 b, a transiting warm brown dwarf orbiting a late B star, discovered by NASA's Transiting Exoplanet Survey Satellite TESS as TOI-588 b. HIP ...33609 b is a large (R\(_{b}\) = 1.580\(_{-0.070}^{+0.074}\) R\(_{J}\)) brown dwarf on a highly eccentric (e = 0.560\(_{-0.031}^{+0.029}\)) orbit with a 39-day period. The host star is a bright (V = 7.3 mag), T\(_{eff}\) = 10,400\(_{-660}^{+800}\) K star with a mass of M\(_{*}\) = 2.383\(_{-0.095}^{+0.10}\) M\(_{\odot}\) and radius of R\(_{*}\) = 1.863\(_{-0.082}^{+0.087}\) R\(_{\odot}\), making it the hottest transiting brown dwarf host star discovered to date. We obtained radial velocity measurements from the CHIRON spectrograph confirming the companion's mass of M\(_{b}\) = 68.0\(_{-7.1}^{+7.4}\) M\(_{J}\) as well as the host star's rotation rate (\(vsini_{*} = 55.6 \pm 1.8\) km/s). We also present the discovery of a new comoving group of stars, designated as MELANGE-6, and determine that HIP 33609 is a member. We use a combination of rotation periods and isochrone models fit to the cluster members to estimate an age of 150 \(\pm\) 25 Myr. With a measured mass, radius, and age, HIP 33609 b becomes a benchmark for substellar evolutionary models.
Large sub-Neptunes are uncommon around the coolest stars in the Galaxy and are rarer still around those that are metal-poor. However, owing to the large planet-to-star radius ratio, these planets are ...highly suitable for atmospheric study via transmission spectroscopy in the infrared, such as with JWST. Here we report the discovery and validation of a sub-Neptune orbiting the thick-disk, mid-M dwarf star TOI-2406. We first infer properties of the host star by analysing the star's near-infrared spectrum, spectral energy distribution, and Gaia parallax. We use multi-band photometry to confirm that the transit event is on-target and achromatic, and we statistically validate the TESS signal as a transiting exoplanet. We then determine physical properties of the planet through global transit modelling of the TESS and ground-based time-series data. We determine the host to be a metal-poor M4V star, located at a distance of 56 pc, with a sub-solar metallicity \((\mathrm{Fe/H = -0.38 \pm 0.07})\), and a member of the thick disk. The planet is a relatively large sub-Neptune for the M-dwarf planet population, with \(\mathrm{R_p = 2.94 \pm 0.17} \mathrm{R_\oplus}\) and \(\mathrm{P = 3.077}\) d, producing transits of 2% depth. We note the orbit has a non-zero eccentricity to 3\(\mathrm{\sigma}\), prompting questions about the dynamical history of the system. This system is an interesting outcome of planet formation and presents a benchmark for large-planet formation around metal-poor, low-mass stars. The system warrants further study, in particular radial velocity follow-up to determine the planet mass and constrain possible bound companions. Furthermore, TOI-2406 b is a good target for future atmospheric study through transmission spectroscopy, particularly in the category of warm sub-Neptunes.
The optical and X-ray transmission of the test samples of optical blocking filters (OBF) for the XIS (X-ray Imaging Spectrometer; CCD camera onboard the ASTRO-E satellite) were measured. Unexpected ...high transmission of optical lights was found. The oxidation of the aluminum layer is one possible cause of the high optical transmission.
We report the discovery of TOI-2119b, a transiting brown dwarf (BD) that orbits and is completely eclipsed by an active M-dwarf star. Using light curve data from the Transiting Exoplanet Survey ...Satellite mission and follow-up high-resolution Doppler spectroscopic observations, we find the BD has a radius of \(R_b = 1.08 \pm 0.03{\rm R_J}\), a mass of \(M_b = 64.4 \pm 2.3{\rm M_J}\), an orbital period of \(P = 7.200865 \pm 0.00002\) days, and an eccentricity of \(e=0.337\pm 0.002\). The host star has a mass of \(M_\star = 0.53 \pm 0.02{\rm M_\odot}\), a radius of \(R_\star= 0.50 \pm 0.01{\rm R_\odot}\), an effective temperature of \(T_{\rm eff} = 3621 \pm 48\)K, and a metallicity of \(\rm Fe/H=+0.06\pm 0.08\). TOI-2119b joins an emerging population of transiting BDs around M-dwarf host stars, with TOI-2119 being the ninth such system. These M-dwarf--brown dwarf systems typically occupy mass ratios near \(q = M_b/M_\star \approx 0.1-0.2\), which separates them from the typical mass ratios for systems with transiting substellar objects and giant exoplanets that orbit more massive stars. The nature of the secondary eclipse of the BD by the star enables us to estimate the effective temperature of the substellar object to be \(2030\pm 84\)K, which is consistent with predictions by substellar evolutionary models.
We report the discovery of ten short-period giant planets (TOI-2193A b, TOI-2207 b, TOI-2236 b, TOI-2421 b, TOI-2567 b, TOI-2570 b, TOI-3331 b, TOI-3540A b, TOI-3693 b, TOI-4137 b). All of the ...planets were identified as planet candidates based on periodic flux dips observed by NASA's Transiting Exoplanet Survey Satellite (TESS). The signals were confirmed to be from transiting planets using ground-based time-series photometry, high angular resolution imaging, and high-resolution spectroscopy coordinated with the TESS Follow-up Observing Program. The ten newly discovered planets orbit relatively bright F and G stars (\(G < 12.5\),~\(T_\mathrm{eff}\) between 4800 and 6200 K). The planets' orbital periods range from 2 to 10~days, and their masses range from 0.2 to 2.2 Jupiter masses. TOI-2421 b is notable for being a Saturn-mass planet and TOI-2567 b for being a ``sub-Saturn'', with masses of \(0.322\pm 0.073\) and \(0.195\pm 0.030\) Jupiter masses, respectively. In most cases, we have little information about the orbital eccentricities. Two exceptions are TOI-2207 b, which has an 8-day period and a detectably eccentric orbit (\(e = 0.17\pm0.05\)), and TOI-3693 b, a 9-day planet for which we can set an upper limit of \(e < 0.052\). The ten planets described here are the first new planets resulting from an effort to use TESS data to unify and expand on the work of previous ground-based transit surveys in order to create a large and statistically useful sample of hot Jupiters.
We present the discovery of two new transiting extrasolar planet candidates identified as TOI-1296.01 and TOI-1298.01 by the Transiting Exoplanet Survey Satellite (TESS). The planetary nature of ...these candidates has been secured with the SOPHIE high-precision spectrograph through the measurement of the companion's mass with the radial velocity method. Both planets are similar to Saturn in mass and have similar orbital periods of a few days. They, however, show discrepant radii and therefore different densities. The radius discrepancy might be explained by the different levels of irradiation by the host stars. The subgiant star TOI-1296 hosts a low-density planet with 1.2 RJup while the less luminous, lower-size star TOI-1298 hosts a much denser planet with a 0.84 RJup radius, resulting in bulk densities of 0.198 and 0.743 g/cm3, respectively. In addition, both stars are strongly enriched in heavy elements, having metallicities of 0.44 and 0.49 dex, respectively. The planet masses and orbital periods are 0.298 (0.039) MJup and 3.9443715 days for TOI-1296b, and 0.356 (0.032) MJup and 4.537164 days for TOI-1298b.
This study examined the associations among loneliness, stressful life events, urinary cortisol levels, and immunocompetency. Blood and urine were obtained from 33 psychiatric inpatients on the day ...after admission, at which time the patients completed the UCLA Loneliness Scale, the Psychiatric Epidemiology Research Interview Life Events Scale (PERI), and the MMPI. Patients who scored above the median on loneliness had significantly higher urinary cortisol levels. The high loneliness group also had significantly lower levels of natural killer cell activity, as well as a poorer T-lymphocyte response to phytohemagglutinin. The high loneliness subjects described themselves as more distressed than the low loneliness group on the MMPI. There were no consistent significant effects on either the immunologic measures or the MMPI associated with the PERI.
We report the confirmation and mass determination of three hot Jupiters discovered by the Transiting Exoplanet Survey Satellite (TESS) mission: HIP 65Ab (TOI-129, TIC-201248411) is an ...ultra-short-period Jupiter orbiting a bright (V=11.1 mag) K4-dwarf every 0.98 days. It is a massive 3.213 +/- 0.078 Mjup planet in a grazing transit configuration with an impact parameter of b = 1.17 +0.10/-0.08. As a result the radius is poorly constrained, 2.03 +0.61/-0.49 Rjup. The planet's distance to its host star is less than twice the separation at which it would be destroyed by Roche lobe overflow. It is expected to spiral into HIP 65A on a timescale ranging from 80 Myr to a few gigayears, assuming a reduced tidal dissipation quality factor of Qs' = 10^7 - 10^9. We performed a full phase-curve analysis of the TESS data and detected both illumination- and ellipsoidal variations as well as Doppler boosting. HIP 65A is part of a binary stellar system, with HIP 65B separated by 269 AU (3.95 arcsec on sky). TOI-157b (TIC 140691463) is a typical hot Jupiter with a mass of 1.18 +/- 0.13 Mjup and a radius of 1.29 +/- 0.02 Rjup. It has a period of 2.08 days, which corresponds to a separation of just 0.03 AU. This makes TOI-157 an interesting system, as the host star is an evolved G9 sub-giant star (V=12.7). TOI-169b (TIC 183120439) is a bloated Jupiter orbiting a V=12.4 G-type star. It has a mass of 0.79 +/- 0.06 Mjup and a radius of 1.09 +0.08/-0.05 Rjup. Despite having the longest orbital period (P = 2.26 days) of the three planets, TOI-169b receives the most irradiation and is situated on the edge of the Neptune desert. All three host stars are metal rich with Fe/H ranging from 0.18 - 0.24.
We use TESS, Spitzer, ground-based light curves and HARPS spectrograph radial velocity measurements to establish the physical properties of the transiting exoplanet candidate TOI-674b. We perform a ...joint fit of the light curves and radial velocity time series to measure the mass, radius, and orbital parameters of the candidate. We confirm and characterize TOI-674b, a low-density super-Neptune transiting a nearby M dwarf. The host star (TIC 158588995, \(V = 14.2\) mag, \(J = 10.3\) mag) is characterized by its M2V spectral type with \(\mathrm{M}_\star=0.420\pm 0.010\) M\(_\odot\), \(\mathrm{R}_\star = 0.420\pm 0.013\) R\(_\odot\), and \(\mathrm{T}_{\mathrm{eff}} = 3514\pm 57\) K, and is located at a distance \(d=46.16 \pm 0.03\) pc. Combining the available transit light curves plus radial velocity measurements and jointly fitting a circular orbit model, we find an orbital period of \(1.977143 \pm 3\times 10^{-6}\) days, a planetary radius of \(5.25 \pm 0.17\) \(\mathrm{R}_\oplus\), and a mass of \(23.6 \pm 3.3\) \(\mathrm{M}_\oplus\) implying a mean density of \(\rho_\mathrm{p} = 0.91 \pm 0.15\) g cm\(^{-3}\). A non-circular orbit model fit delivers similar planetary mass and radius values within the uncertainties. Given the measured planetary radius and mass, TOI-674b is one of the largest and most massive super-Neptune class planets discovered around an M type star to date. It is also a resident of the so-called Neptunian desert and a promising candidate for atmospheric characterisation using the James Webb Space Telescope.
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