Subscribe to the gold package and get unlimited access to Shamra Academy
Register a new userTOI-220 $b$: a warm sub-Neptune discovered by TESS
250
0
0.0
(
0
)
Ask ChatGPT about the research
No Arabic abstract
In this paper we report the discovery of TOI-220 $b$, a new sub-Neptune detected by the Transiting Exoplanet Survey Satellite (TESS) and confirmed by radial velocity follow-up observations with the HARPS spectrograph. Based on the combined analysis of TESS transit photometry and high precision radial velocity measurements we estimate a planetary mass of 13.8 $pm$ 1.0 M$_{Earth}$ and radius of 3.03 $pm$ 0.15 R$_{Earth}$, implying a bulk density of 2.73 $pm$ 0.47 $textrm{g cm}^{-3}$. TOI-220 $b$ orbits a relative bright (V=10.4) and old (10.1$pm$1.4 Gyr) K dwarf star with a period of $sim$10.69 d. Thus, TOI-220 $b$ is a new warm sub-Neptune with very precise mass and radius determinations. A Bayesian analysis of the TOI-220 $b$ internal structure indicates that due to the strong irradiation it receives, the low density of this planet could be explained with a steam atmosphere in radiative-convective equilibrium and a supercritical water layer on top of a differentiated interior made of a silicate mantle and a small iron core.
rate research
Read More
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.
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.
The future of exoplanet science is bright, as TESS once again demonstrates with the discovery of its longest-period confirmed planet to date. We hereby present HD 21749b (TOI 186.01), a sub-Neptune in a 36-day orbit around a bright (V = 8.1) nearby (16 pc) K4.5 dwarf. TESS measures HD21749b to be 2.61$^{+0.17}_{-0.16}$ $R_{oplus}$, and combined archival and follow-up precision radial velocity data put the mass of the planet at $22.7^{+2.2}_{-1.9}$ $M_{oplus}$. HD 21749b contributes to the TESS Level 1 Science Requirement of providing 50 transiting planets smaller than 4 $R_{oplus}$ with measured masses. Furthermore, we report the discovery of HD 21749c (TOI 186.02), the first Earth-sized ($R_p = 0.892^{+0.064}_{-0.058} R_{oplus}$) planet from TESS. The HD21749 system is a prime target for comparative studies of planetary composition and architecture in multi-planet systems.
We report the discovery of NGTS-11 b (=TOI-1847 b), a transiting Saturn in a 35.46-day orbit around a mid K-type star (Teff=5050 K). We initially identified the system from a single-transit event in a TESS full-frame image light-curve. Following seventy-nine nights of photometric monitoring with an NGTS telescope, we observed a second full transit of NGTS-11 b approximately one year after the TESS single-transit event. The NGTS transit confirmed the parameters of the transit signal and restricted the orbital period to a set of 13 discrete periods. We combined our transit detections with precise radial velocity measurements to determine the true orbital period and measure the mass of the planet. We find NGTS-11 b has a radius of 0.817+0.028-0.032 $R_J$, a mass of 0.344+0.092-0.073 $M_J$, and an equilibrium temperature of just 435+34-32 K, making it one of the coolest known transiting gas giants. NGTS-11 b is the first exoplanet to be discovered after being initially identified as a TESS single-transit event, and its discovery highlights the power of intense photometric monitoring in recovering longer-period transiting exoplanets from single-transit events.
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 exoplanet 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.
Log in to be able to interact and post comments
comments
Fetching comments
Sign in to be able to follow your search criteria
