We report the confirmation and characterisation of TOI-1820 b, TOI-2025 b, and TOI-2158 b, three Jupiter-sized planets on short-period orbits around G-type stars detected by TESS. Through our ...ground-based efforts using the FIES and Tull spectrographs, we have confirmed these planets and characterised their orbits, and find periods of around 4.9 d, 8.9 d, and 8.6 d for TOI-1820 b, TOI-2025 b, and TOI-2158 b, respectively. The sizes of the planets range from 0.96 to 1.14 Jupiter radii, and their masses are in the range from 0.8 to 4.4 Jupiter masses. For two of the systems, namely TOI-2025 and TOI-2158, we see a long-term trend in the radial velocities, indicating the presence of an outer companion in each of the two systems. For TOI-2025 we furthermore find the star to be well aligned with the orbit, with a projected obliquity of 9
−31
+33
°. As these planets are all found in relatively bright systems (
V
~ 10.9–11.6 mag), they are well suited for further studies, which could help shed light on the formation and migration of hot and warm Jupiters.
Abstract
Hot Jupiters—short-period giant planets—were the first extrasolar planets to be discovered, but many questions about their origin remain. NASA’s Transiting Exoplanet Survey Satellite (TESS), ...an all-sky search for transiting planets, presents an opportunity to address these questions by constructing a uniform sample of hot Jupiters for demographic study through new detections and unifying the work of previous ground-based transit surveys. As the first results of an effort to build this large sample of planets, we report here the discovery of 10 new hot Jupiters (TOI-2193A b, TOI-2207b, TOI-2236b, TOI-2421b, TOI-2567b, TOI-2570b, TOI-3331b, TOI-3540A b, TOI-3693b, TOI-4137b). All of the planets were identified as planet candidates based on periodic flux dips observed by TESS, and were subsequently confirmed using ground-based time-series photometry, high-angular-resolution imaging, and high-resolution spectroscopy coordinated with the TESS Follow-up Observing Program. The 10 newly discovered planets orbit relatively bright F and G stars (
G
< 12.5,
T
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-2421b is notable for being a Saturn-mass planet and TOI-2567b for being a “sub-Saturn,” with masses of 0.322 ± 0.073 and 0.195 ± 0.030 Jupiter masses, respectively. We also measured a detectably eccentric orbit (
e
= 0.17 ± 0.05) for TOI-2207b, a planet on an 8 day orbit, while placing an upper limit of
e
< 0.052 for TOI-3693b, which has a 9 day orbital period. The 10 planets described here represent an important step toward using TESS to create a large and statistically useful sample of hot Jupiters.
Abstract
We present the discovery of TOI-1420b, an exceptionally low-density (
ρ
= 0.08 ±
0.02
g cm
−3
) transiting planet in a
P
= 6.96 days orbit around a late G-dwarf star. Using transit ...observations from TESS, LCOGT, Observatoire Privé du Mont, Whitin, Wendelstein, OAUV, Ca l’Ou, and KeplerCam, along with radial velocity observations from HARPS-N and NEID, we find that the planet has a radius of
R
p
= 11.9 ± 0.3
R
⊕
and a mass of
M
p
= 25.1 ± 3.8
M
⊕
. TOI-1420b is the largest known planet with a mass less than 50
M
⊕
, indicating that it contains a sizeable envelope of hydrogen and helium. We determine TOI-1420b’s envelope mass fraction to be
f
env
=
82
−
6
+
7
%
, suggesting that runaway gas accretion occurred when its core was at most four to five times the mass of the Earth. TOI-1420b is similar to the planet WASP-107b in mass, radius, density, and orbital period, so a comparison of these two systems may help reveal the origins of close-in low-density planets. With an atmospheric scale height of 1950 km, a transmission spectroscopy metric of 580, and a predicted Rossiter–McLaughlin amplitude of about 17 m s
−1
, TOI-1420b is an excellent target for future atmospheric and dynamical characterization.
Abstract
Close-in gas giants present a surprising range of stellar obliquity, the angle between a planet’s orbital axis and its host star’s spin axis. It is unclear whether the obliquities reflect ...the planets’ dynamical history (e.g., aligned for in situ formation or disk migration versus misaligned for high-eccentricity tidal migration) or whether other mechanisms (e.g., primordial misalignment or planet–star interactions) are more important in sculpting the obliquity distribution. Here we present the stellar obliquity measurement of TOI-1268 (TIC-142394656,
V
mag
∼ 10.9), a young K-type dwarf hosting an 8.2 day period, Saturn-sized planet. TOI-1268’s lithium abundance and rotation period suggest the system age between the ages of the Pleiades cluster (∼120 Myr) and the Prasepe cluster (∼670 Myr). Using the newly commissioned NEID spectrograph, we constrain the stellar obliquity of TOI-1268 via the Rossiter–McLaughlin effect from both radial velocity and Doppler tomography signals. The 3
σ
upper bounds of the projected stellar obliquity ∣
λ
∣ from both models are below 60°. The large host star separation (
a
/
R
⋆
∼ 17), combined with the system’s young age, makes it unlikely that the planet has realigned its host star. The stellar obliquity measurement of TOI-1268 probes the architecture of a young gas giant beyond the reach of tidal realignment (
a
/
R
⋆
≳ 10) and reveals an aligned or slightly misaligned system.
Abstract Hot Jupiters were many of the first exoplanets discovered in the 1990s, but in the decades since their discovery the mysteries surrounding their origins have remained. Here we present nine ...new hot Jupiters (TOI-1855 b, TOI-2107 b, TOI-2368 b, TOI-3321 b, TOI-3894 b, TOI-3919 b, TOI-4153 b, TOI-5232 b, and TOI-5301 b) discovered by NASA’s TESS mission and confirmed using ground-based imaging and spectroscopy. These discoveries are the first in a series of papers named the Migration and Evolution of giant ExoPlanets survey and are part of an ongoing effort to build a complete sample of hot Jupiters orbiting FGK stars, with a limiting Gaia G -band magnitude of 12.5. This effort aims to use homogeneous detection and analysis techniques to generate a set of precisely measured stellar and planetary properties that is ripe for statistical analysis. The nine planets presented in this work occupy a range of masses (0.55 M J < M P < 3.88 M J ) and sizes (0.967 R J < R P < 1.438 R J ) and orbit stars that have an effective temperature in the range of 5360 K < T eff < 6860 K with Gaia G -band magnitudes ranging from 11.1 to 12.7. Two of the planets in our sample have detectable orbital eccentricity: TOI-3919 b ( e = 0.259 − 0.036 + 0.033 ) and TOI-5301 b ( e = 0.33 − 0.10 + 0.11 ). These eccentric planets join a growing sample of eccentric hot Jupiters that are consistent with high-eccentricity tidal migration, one of the three most prominent theories explaining hot Jupiter formation and evolution.
Abstract
We present the discovery of a highly irradiated and moderately inflated ultrahot Jupiter, TOI-1431b/MASCARA-5 b (HD 201033b), first detected by NASA’s Transiting Exoplanet Survey Satellite ...mission (TESS) and the Multi-site All-Sky Camera (MASCARA). The signal was established to be of planetary origin through radial velocity measurements obtained using SONG, SOPHIE, FIES, NRES, and EXPRES, which show a reflex motion of
K
= 294.1 ± 1.1 m s
−1
. A joint analysis of the TESS and ground-based photometry and radial velocity measurements reveals that TOI-1431b has a mass of
M
p
= 3.12 ± 0.18
M
J
(990 ± 60
M
⊕
), an inflated radius of
R
p
= 1.49 ± 0.05
R
J
(16.7 ± 0.6
R
⊕
), and an orbital period of
P
= 2.650237 ± 0.000003 days. Analysis of the spectral energy distribution of the host star reveals that the planet orbits a bright (
V
= 8.049 mag) and young (
0.29
−
0.19
+
0.32
Gyr) Am type star with
T
eff
=
7690
−
250
+
400
K, resulting in a highly irradiated planet with an incident flux of
〈
F
〉
=
7.24
−
0.64
+
0.68
×
10
9
erg s
−1
cm
−2
(
5300
−
470
+
500
S
⊕
) and an equilibrium temperature of
T
eq
= 2370 ± 70 K. TESS photometry also reveals a secondary eclipse with a depth of
127
−
5
+
4
ppm as well as the full phase curve of the planet’s thermal emission in the red-optical. This has allowed us to measure the dayside and nightside temperature of its atmosphere as
T
day
= 3004 ± 64 K and
T
night
= 2583 ± 63 K, the second hottest measured nightside temperature. The planet’s low day/night temperature contrast (∼420 K) suggests very efficient heat transport between the dayside and nightside hemispheres. Given the host star brightness and estimated secondary eclipse depth of ∼1000 ppm in the
K
band, the secondary eclipse is potentially detectable at near-IR wavelengths with ground-based facilities, and the planet is ideal for intensive atmospheric characterization through transmission and emission spectroscopy from space missions such as the James Webb Space Telescope and the Atmospheric Remote-sensing Infrared Exoplanet Large-survey.
Abstract
We present the discovery of TOI-3235 b, a short-period Jupiter orbiting an M dwarf with a stellar mass close to the critical mass at which stars transition from partially to fully ...convective. TOI-3235 b was first identified as a candidate from TESS photometry and confirmed with radial velocities from ESPRESSO and ground-based photometry from HATSouth, MEarth-South, TRAPPIST-South, LCOGT, and ExTrA. We find that the planet has a mass of 0.665 ± 0.025
M
J
and a radius of 1.017 ± 0.044
R
J
. It orbits close to its host star, with an orbital period of 2.5926 days but has an equilibrium temperature of ≈ 604 K, well below the expected threshold for radius inflation of hot Jupiters. The host star has a mass of 0.3939 ± 0.0030
M
☉
, a radius of 0.3697 ± 0.0018
R
☉
, an effective temperature of 3389 K, and a
J
-band magnitude of 11.706 ± 0.025. Current planet formation models do not predict the existence of gas giants such as TOI-3235 b around such low-mass stars. With a high transmission spectroscopy metric, TOI-3235 b is one of the best-suited giants orbiting M dwarfs for atmospheric characterization.
ABSTRACT
We present the confirmation of a hot super-Neptune with an exterior Neptune companion orbiting a bright (V = 10.1 mag) F-dwarf identified by the Transiting Exoplanet Survey Satellite ...(TESS). The two planets, observed in sectors 45, 46, and 48 of the TESS extended mission, are $4.74_{-0.14}^{+0.16}$ and $3.86_{-0.16}^{+0.17}$ R⊕ with $5.4588385_{-0.0000072}^{+0.0000070}$ and $17.8999_{-0.0013}^{+0.0018}$ d orbital periods, respectively. We also obtained precise space-based photometric follow-up of the system with ESA’s CHaracterising ExOplanets Satellite to constrain the radius and ephemeris of TOI-5126 b. TOI-5126 b is located in the ‘hot Neptune Desert’ and is an ideal candidate for follow-up transmission spectroscopy due to its high-predicted equilibrium temperature (Teq = ${1442}_{-40}^{+46}$ K) implying a cloud-free atmosphere. TOI-5126 c is a warm Neptune (Teq = $971_{-27}^{+31}$ K) also suitable for follow-up. Tentative transit timing variations have also been identified in analysis, suggesting the presence of at least one additional planet, however this signal may be caused by spot-crossing events, necessitating further precise photometric follow-up to confirm these signals.
Abstract
NASA’s Transiting Exoplanet Survey Satellite (TESS) is an all-sky survey mission designed to find transiting exoplanets orbiting nearby bright stars. It has identified more than 329 ...transiting exoplanets, and almost 6000 candidates remain unvalidated. In this manuscript, we discuss the findings from the ongoing Validation of Transiting Exoplanets using Statistical Tools (VaTEST) project, which aims to validate new exoplanets for further characterization. We validated 11 new exoplanets by examining the light curves of 24 candidates using the
LATTE
and
TESS-Plot
tools and computing the false-positive probabilities using the statistical validation tool
TRICERATOPS
. These include planets suitable for atmospheric characterization using transmission spectroscopy (TOI-2194b), emission spectroscopy (TOI-3082b and TOI-5704b) and for both transmission and emission spectroscopy (TOI-672b, TOI-1694b, and TOI-2443b). Our validated planets have one super-Earth (TOI-2194b) orbiting a bright (
V
= 8.42 mag), metal-poor (Fe/H = −0.3720 ± 0.1) star, and one short-period Neptune-like planet (TOI-5704) in the hot-Neptune desert. In total, we validated one super-Earth, seven sub-Neptunes, one Neptune-like, and two sub-Saturn or super-Neptune-like exoplanets. Additionally, we identify five likely planet candidates (TOI-323, TOI-1180, TOI-2200, TOI-2408, and TOI-3913), which can be further studied to establish their planetary nature.
ABSTRACT
We report the discovery of three transiting low-mass companions to aged stars: a brown dwarf (TOI-2336b) and two objects near the hydrogen burning mass limit (TOI-1608b and TOI-2521b). These ...three systems were first identified using data from the Transiting Exoplanet Survey Satellite (TESS). TOI-2336b has a radius of 1.05 ± 0.04 RJ, a mass of 69.9 ± 2.3 MJ and an orbital period of 7.71 d. TOI-1608b has a radius of 1.21 ± 0.06 RJ, a mass of 90.7 ± 3.7 MJ and an orbital period of 2.47 d. TOI-2521b has a radius of 1.01 ± 0.04 RJ, a mass of 77.5 ± 3.3 MJ, and an orbital period of 5.56 d. We found all these low-mass companions are inflated. We fitted a relation between radius, mass, and incident flux using the sample of known transiting brown dwarfs and low-mass M dwarfs. We found a positive correlation between the flux and the radius for brown dwarfs and for low-mass stars that is weaker than the correlation observed for giant planets. We also found that TOI-1608 and TOI-2521 are very likely to be spin-orbit synchronized, leading to the unusually rapid rotation of the primary stars considering their evolutionary stages. Our estimates indicate that both systems have much shorter spin-orbit synchronization time-scales compared to their ages. These systems provide valuable insights into the evolution of stellar systems with brown dwarf and low-mass stellar companions influenced by tidal effects.
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