Subscribe to the gold package and get unlimited access to Shamra Academy
Register a new userA Hot Saturn Orbiting An Oscillating Late Subgiant Discovered by TESS
483
0
0.0
(
0
)
Ask ChatGPT about the research
No Arabic abstract
We present the discovery of TOI-197.01, the first transiting planet identified by the Transiting Exoplanet Survey Satellite (TESS) for which asteroseismology of the host star is possible. TOI-197 (HIP116158) is a bright (V=8.2 mag), spectroscopically classified subgiant which oscillates with an average frequency of about 430 muHz and displays a clear signature of mixed modes. The oscillation amplitude confirms that the redder TESS bandpass compared to Kepler has a small effect on the oscillations, supporting the expected yield of thousands of solar-like oscillators with TESS 2-minute cadence observations. Asteroseismic modeling yields a robust determination of the host star radius (2.943+/-0.064 Rsun), mass (1.212 +/- 0.074 Msun) and age (4.9+/-1.1 Gyr), and demonstrates that it has just started ascending the red-giant branch. Combining asteroseismology with transit modeling and radial-velocity observations, we show that the planet is a hot Saturn (9.17+/-0.33 Rearth) with an orbital period of ~14.3 days, irradiance of 343+/-24 Fearth, moderate mass (60.5 +/- 5.7 Mearth) and density (0.431+/-0.062 gcc). The properties of TOI-197.01 show that the host-star metallicity - planet mass correlation found in sub-Saturns (4-8 Rearth) does not extend to larger radii, indicating that planets in the transition between sub-Saturns and Jupiters follow a relatively narrow range of densities. With a density measured to ~15%, TOI-197.01 is one of the best characterized Saturn-sized planets to date, augmenting the small number of known transiting planets around evolved stars and demonstrating the power of TESS to characterize exoplanets and their host stars using asteroseismology.
rate research
Read More
While the population of confirmed exoplanets continues to grow, the sample of confirmed transiting planets around evolved stars is still limited. We present the discovery and confirmation of a hot Jupiter orbiting TOI-2184 (TIC 176956893), a massive evolved subgiant ($M_star= 1.53 pm 0.12 M_odot$, $R_star= 2.90 pm 0.14 R_odot$) in the $textit{TESS}$ Southern Continuous Viewing Zone. The planet was flagged as a false positive by the $textit{TESS}$ Quick-Look Pipeline due to periodic systematics introducing a spurious depth difference between even and odd transits. Using a new pipeline to remove background scattered light in $textit{TESS}$ Full Frame Image (FFI) data, we combine space-based $textit{TESS}$ photometry, ground-based photometry, and ground-based radial velocity measurements to report a planet radius of $R_p= 1.017 pm 0.051 R_J$ and mass of $M_p= 0.65 pm 0.16 M_J$. For a planet so close to its star, the mass and radius of TOI-2184b are unusually well matched to those of Jupiter. We find that the radius of TOI-2184b is smaller than theoretically predicted based on its mass and incident flux, providing a valuable new constraint on the timescale of post-main-sequence planet inflation. The discovery of TOI-2184b demonstrates the feasibility of detecting planets around faint ($textit{TESS}$ magnitude $>12$) post-main sequence stars and suggests that many more similar systems are waiting to be detected in the $textit{TESS}$ FFIs, whose confirmation may elucidate the final stages of planetary system evolution.
We present the discovery of WASP-39b, a highly inflated transiting Saturn-mass planet orbiting a late G-type dwarf star with a period of $4.055259 pm 0.000008$,d, Transit Epoch T$_{0}=2455342.9688pm0.0002$,(HJD), of duration $0.1168 pm 0.0008$,d. A combined analysis of the WASP photometry, high-precision follow-up transit photometry, and radial velocities yield a planetary mass of $mpl=0.28pm0.03,mj$ and a radius of $rpl=1.27pm0.04,rj$, resulting in a mean density of $0.14 pm 0.02,rhoj$. The stellar parameters are mass $mstar = 0.93 pm 0.03,msun$, radius $rstar = 0.895pm 0.23,rsun$, and age $9^{+3}_{-4}$,Gyr. Only WASP-17b and WASP-31b have lower densities than WASP-39b, although they are slightly more massive and highly irradiated planets. From our spectral analysis, the metallicity of WASP-39 is measured to be feh,$= -0.12pm0.1$,dex, and we find the planet to have an equilibrium temperature of $1116^{+33}_{-32}$,K,. Both values strengthen the observed empirical correlation between these parameters and the planetary radius for the known transiting Saturn-mass planets.
We report the detection of a transiting super-Earth-sized planet (R=1.39+-0.09 Rearth) in a 1.4-day orbit around L 168-9 (TOI-134),a bright M1V dwarf (V=11, K=7.1) located at 25.15+-0.02 pc. The host star was observed in the first sector of the Transiting Exoplanet Survey Satellite (TESS) mission and, for confirmation and planet mass measurement, was followed up with ground-based photometry, seeing-limited and high-resolution imaging, and precise radial velocity (PRV) observations using the HARPS and PFS spectrographs. Combining the TESS data and PRV observations, we find the mass of L168-9 b to be 4.60+-0.56 Mearth, and thus the bulk density to be 1.74+0.44-0.33 times larger than that of the Earth. The orbital eccentricity is smaller than 0.21 (95% confidence). This planet is a Level One Candidate for the TESS Missions scientific objective - to measure the masses of 50 small planets - and is one of the most observationally accessible terrestrial planets for future atmospheric characterization.
We report on the confirmation of a transiting giant planet around the relatively hot (Teff = 6801 $pm$ 56 K) star HD2685, whose transit signal was detected in Sector 1 data of the TESS mission. We confirmed the planetary nature of the transit signal by using Doppler velocimetric measurements with CHIRON, CORALIE and FEROS, as well as photometric data with CHAT and LCOGT. From the photometry and radial velocities joint analysis, we derived the following parameters for HD2685 $b$: $P$=4.12692$pm$0.00004 days, M$_P$=1.18 $pm$ 0.09 $M_J$ and $R_P$=1.44 $pm$ 0.01 $R_J$. This system is a typical example of an inflated transiting Hot-Jupiter in a circular orbit. Given the host star apparent visual magnitude ($V$ = 9.6 mag), this is one of the brightest known stars hosting a transiting Hot-Jupiter, and a good example of the upcoming systems that will be detected by TESS during the two-year primary mission. This is also an excellent target for future ground and space based atmospheric characterization as well as a good candidate for measuring the projected spin-orbit misalignment angle via the Rossiter-McLaughlin effect.
We report the discovery and confirmation of two new hot Jupiters discovered by the Transiting Exoplanet Survey Satellite (TESS): TOI 564 b and TOI 905 b. The transits of these two planets were initially observed by TESS with orbital periods of 1.651 d and 3.739 d, respectively. We conducted follow-up observations of each system from the ground, including photometry in multiple filters, speckle interferometry, and radial velocity measurements. For TOI 564 b, our global fitting revealed a classical hot Jupiter with a mass of $1.463^{+0.10}_{-0.096} M_J$ and a radius of $1.02^{+0.71}_{-0.29} R_J$. TOI 905 b is a classical hot Jupiter as well, with a mass of $0.667^{+0.042}_{-0.041} M_J$ and radius of $1.171^{+0.053}_{-0.051} R_J$. Both planets orbit Sun-like, moderately bright, mid-G dwarf stars with V ~ 11. While TOI 905 b fully transits its star, we found that TOI 564 b has a very high transit impact parameter of $0.994^{+0.083}_{-0.049}$, making it one of only ~20 known systems to exhibit a grazing transit and one of the brightest host stars among them. TOI 564 b is therefore one of the most attractive systems to search for additional non-transiting, smaller planets by exploiting the sensitivity of grazing transits to small changes in inclination and transit duration over the time scale of several years.
Log in to be able to interact and post comments
comments
Fetching comments
Sign in to be able to follow your search criteria
