2 research outputs found
TOI-5126: A hot super-Neptune and warm Neptune pair discovered by and
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
(). The two
planets, observed in sectors 45, 46 and 48 of the extended
mission, are and
with d and
d orbital periods, respectively. We also obtained
precise space based photometric follow-up of the system with ESAs
() 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 ( K) implying a cloud-free atmosphere. TOI-5126 c is a warm
Neptune ( K) also suitable for follow-up. Tentative
transit timing variations (TTVs) 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.Comment: Accepted in MNRAS, 18 pages, 14 figure
TOI-1695 b: A Water World Orbiting an Early-M Dwarf in the Planet Radius Valley
Abstract
Characterizing the bulk compositions of transiting exoplanets within the M dwarf radius valley offers a unique means to establish whether the radius valley emerges from an atmospheric mass-loss process or is imprinted by planet formation itself. We present the confirmation of such a planet orbiting an early-M dwarf (T
mag = 11.0294 ± 0.0074, M
s
= 0.513 ± 0.012 M
⊙, R
s
= 0.515 ± 0.015 R
⊙, and T
eff = 3690 ± 50 K): TOI-1695 b (P = 3.13 days and
R
p
=
1.90
−
0.14
+
0.16
R
⊕
). TOI-1695 b’s radius and orbital period situate the planet between model predictions from thermally driven mass loss versus gas depleted formation, offering an important test case for radius valley emergence models around early-M dwarfs. We confirm the planetary nature of TOI-1695 b based on five sectors of TESS data and a suite of follow-up observations including 49 precise radial velocity measurements taken with the HARPS-N spectrograph. We measure a planetary mass of 6.36 ± 1.00 M
⊕, which reveals that TOI-1695 b is inconsistent with a purely terrestrial composition of iron and magnesium silicate, and instead is likely a water-rich planet. Our finding that TOI-1695 b is not terrestrial is inconsistent with the planetary system being sculpted by thermally driven mass loss. We present a statistical analysis of seven well-characterized planets within the M dwarf radius valley demonstrating that a thermally driven mass-loss scenario is unlikely to explain this population.</jats:p