اشترك بالحزمة الذهبية واحصل على وصول غير محدود شمرا أكاديميا
تسجيل مستخدم جديدA sub-Neptune and a non-transiting Neptune-mass companion unveiled by ESPRESSO around the bright late-F dwarf HD 5278 (TOI-130)
87
0
0.0
(
0
)
اسأل ChatGPT حول البحث
ﻻ يوجد ملخص باللغة العربية
[Abridged] We exploit the extreme radial velocity (RV) precision of the ultra-stable echelle spectrograph ESPRESSO on the VLT to unveil the physical properties of the transiting sub-Neptune TOI-130 b, uncovered by TESS orbiting the nearby, bright, late F-type star HD 5278 (TOI-130) with a period $P_{rm b}=14.3$. We use 43 ESPRESSO high-resolution spectra and broad-band photometry information to derive accurate stellar atmospheric and physical parameters of HD 5278. We exploit the TESS light curve (LC) and spectroscopic diagnostics to gauge the impact of stellar activity on the ESPRESSO RVs. We perform a joint ESPRESSO RVs + TESS LC analysis using fully Bayesian frameworks to determine the system parameters. The updated stellar parameters of HD 5278 are T$_mathrm{eff}=6203pm64$ K, $log g =4.50pm0.11$ dex, [Fe/H]=$-0.12pm0.04$ dex, M$_star=1.126_{-0.035}^{+0.036}$ M$_odot$ and R$_star=1.194_{-0.016}^{+0.017}$ R$_odot$. We determine HD 5278 bs mass and radius to be $M_{rm b} = 7.8_{-1.4}^{+1.5}$ M$_oplus$ and $R_{rm b} = 2.45pm0.05$ R$_oplus$. The derived mean density, $varrho_{rm b} = 2.9_{-0.5}^{+0.6}$ g cm$^{-3}$, is consistent with a bulk composition with a substantial ($sim30%$) water mass fraction and a gas envelope comprising $sim17%$ of the measured radius. Given the host brightness and irradiation levels, HD 5278 b is one of the best targets orbiting G-F primaries for follow-up atmospheric characterization measurements with HST and JWST. We discover a second, non-transiting companion in the system, with a period $P_{rm c}=40.87_{-0.17}^{+0.18}$ days and a minimum mass $M_{rm c}sin i_{rm c} =18.4_{-1.9}^{+1.8}$ M$_oplus$. We study emerging trends in the growing population of transiting sub-Neptunes, and provide statistical evidence for a low occurrence of close-in, $10-15$ M$_oplus$ companions around G-F primaries with $T_mathrm{eff}gtrsim5500$ K.
قيم البحث
اقرأ أيضاً
We report the discovery and characterization of a transiting warm sub-Neptune planet around the nearby bright ($V=8.75$ mag, $K=7.15$ mag) solar twin HD 183579, delivered by the Transiting Exoplanet Survey Satellite (TESS). The host star is located $
56.8pm0.1$ pc away with a radius of $R_{ast}=0.97pm0.02 R_{odot}$ and a mass of $M_{ast}=1.03pm0.05 M_{odot}$. We confirm the planetary nature by combining space and ground-based photometry, spectroscopy, and imaging. We find that HD 183579b (TOI-1055b) has a radius of $R_{p}=3.53pm0.13 R_{oplus}$ on a $17.47$ day orbit with a mass of $M_{p}=11.2pm5.4 M_{oplus}$ ($3sigma$ mass upper limit of $27.4 M_{oplus}$). HD 183579b is the fifth brightest known sub-Neptune planet system in the sky, making it an excellent target for future studies of the interior structure and atmospheric properties. By performing a line-by-line differential analysis using the high resolution and signal-to-noise ratio HARPS spectra, we find that HD 183579 joins the typical solar twin sample, without a statistically significant refractory element depletion.
We report the discovery and characterisation of a super-Earth and a sub-Neptune transiting the bright ($K=8.8$), quiet, and nearby (37 pc) M3V dwarf TOI-1266. We validate the planetary nature of TOI-1266 b and c using four sectors of TESS photometry
and data from the newly-commissioned 1-m SAINT-EX telescope located in San Pedro Martir (Mexico). We also include additional ground-based follow-up photometry as well as high-resolution spectroscopy and high-angular imaging observations. The inner, larger planet has a radius of $R=2.37_{-0.12}^{+0.16}$ R$_{oplus}$ and an orbital period of 10.9 days. The outer, smaller planet has a radius of $R=1.56_{-0.13}^{+0.15}$ R$_{oplus}$ on an 18.8-day orbit. The data are found to be consistent with circular, co-planar and stable orbits that are weakly influenced by the 2:1 mean motion resonance. Our TTV analysis of the combined dataset enables model-independent constraints on the masses and eccentricities of the planets. We find planetary masses of $M_mathrm{p}$ = $13.5_{-9.0}^{+11.0}$ $mathrm{M_{oplus}}$ ($<36.8$ $mathrm{M_{oplus}}$ at 2-$sigma$) for TOI-1266 b and $2.2_{-1.5}^{+2.0}$ $mathrm{M_{oplus}}$ ($<5.7$ $mathrm{M_{oplus}}$ at 2-$sigma$) for TOI-1266 c. We find small but non-zero orbital eccentricities of $0.09_{-0.05}^{+0.06}$ ($<0.21$ at 2-$sigma$) for TOI-1266 b and $0.04pm0.03$ ($<0.10$ at 2-$sigma$) for TOI-1266 c. The equilibrium temperatures of both planets are of $413pm20$ K and $344pm16$ K, respectively, assuming a null Bond albedo and uniform heat redistribution from the day-side to the night-side hemisphere. The host brightness and negligible activity combined with the planetary system architecture and favourable planet-to-star radii ratios makes TOI-1266 an exquisite system for a detailed characterisation.
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 transmis
sion 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 stars 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.
We present the confirmation of a new sub-Neptune close to the transition between super-Earths and sub-Neptunes transiting the M2 dwarf TOI- 269 (TIC 220479565, V = 14.4 mag, J = 10.9 mag, Rstar = 0.40 Rsun, Mstar = 0.39 Msun, d = 57 pc). The exoplane
t candidate has been identified in multiple TESS sectors, and validated with high-precision spectroscopy from HARPS and ground-based photometric follow-up from ExTrA and LCO-CTIO. We determined mass, radius, and bulk density of the exoplanet by jointly modeling both photometry and radial velocities with juliet. The transiting exoplanet has an orbital period of P = 3.6977104 +- 0.0000037 days, a radius of 2.77 +- 0.12 Rearth, and a mass of 8.8 +- 1.4 Mearth. Since TOI-269 b lies among the best targets of its category for atmospheric characterization, it would be interesting to probe the atmosphere of this exoplanet with transmission spectroscopy in order to compare it to other sub-Neptunes. With an eccentricity e = 0.425+0.082-0.086, TOI-269 b has one of the highest eccentricities of the exoplanets with periods less than 10 days. The star being likely a few Gyr old, this system does not appear to be dynamically young. We surmise TOI-269 b may have acquired its high eccentricity as it migrated inward through planet-planet interactions.
We present the bright (V$_{mag} = 9.12$), multi-planet system TOI-431, characterised with photometry and radial velocities. We estimate the stellar rotation period to be $30.5 pm 0.7$ days using archival photometry and radial velocities. TOI-431b is
a super-Earth with a period of 0.49 days, a radius of 1.28 $pm$ 0.04 R$_{oplus}$, a mass of $3.07 pm 0.35$ M$_{oplus}$, and a density of $8.0 pm 1.0$ g cm$^{-3}$; TOI-431d is a sub-Neptune with a period of 12.46 days, a radius of $3.29 pm 0.09$ R$_{oplus}$, a mass of $9.90^{+1.53}_{-1.49}$ M$_{oplus}$, and a density of $1.36 pm 0.25$ g cm$^{-3}$. We find a third planet, TOI-431c, in the HARPS radial velocity data, but it is not seen to transit in the TESS light curves. It has an $M sin i$ of $2.83^{+0.41}_{-0.34}$ M$_{oplus}$, and a period of 4.85 days. TOI-431d likely has an extended atmosphere and is one of the most well-suited TESS discoveries for atmospheric characterisation, while the super-Earth TOI-431b may be a stripped core. These planets straddle the radius gap, presenting an interesting case-study for atmospheric evolution, and TOI-431b is a prime TESS discovery for the study of rocky planet phase curves.
سجل دخول لتتمكن من نشر تعليقات
التعليقات
جاري جلب التعليقات
سجل دخول لتتمكن من متابعة معايير البحث التي قمت باختيارها
