Gale crater shows infilling of lava of basaltic origin mainly coming from the south via Farah Vallis. Using available Thermal Emission Imaging System (THEMIS) images, Mars Orbiter Laser Altimeter ...(MOLA) topographic data, Compact Reconnaissance Imaging Spectrometer for Mars (CRISM) mineralogical data, and geochemical analyses taken in situ by the Mars Science Laboratory (MSL) in different locations of the crater, we focused on the possible origin and the main path of the lava that filled Gale crater. We found that: 1) the K/Ar age of the basaltic rocks on Gale's floor is consistent with the age of formation of Tyrrhenus Mons derived from the southern polar giant impact (SPGI) model; 2) the Aeolis Mensae region does not show evidence for interaction between lava coming from the north (Elysium Mons) and lava coming from the south (Tyrrhenus Mons); 3) the geomorphological analysis shows that Farah Vallis is the convergence of a complex network of volcanic channels that can be tracked back to the lava fields of Tyrrhenus Mons; 4) a one-dimensional model of lava along the observed path, using an Adirondrack basalt composition for the substrate, shows that lava from Tyrrhenus Mons is thermally capable of flowing the entire distance to Gale before cooling down. This evidence is consistent with the lava fill observed at Gusev crater.
•Gale crater is filled by low viscosity basaltic lava, similar to Gusev crater.•Lava traveled from Tyrrhenus Mons directly to Gale crater.•Farah Vallis is the main entrance for lava coming from Tyrrhenus Mons.•Computer simulations are consistent with the presented geological observations.
We report the discovery of TOI-677b,first identified as a candidate in light curves obtained within Sectors 9 and 10 of the Transiting Exoplanet Survey Satellite(TESS)mission and confirmed with ...radial velocities. TOI-677b has a mass of M(p) = 1.236(+0.069,- 0.067) M(J), a radius of R(P)=1.170 ± 0.03 R(J), and orbits its bright host star (V = 9.8 mag) with an orbital period of 11.23660 ± 0.00011 d, on an eccentric orbit with e = 0.435 ± 0.024. The host star has a mass of M(*) = 1.181 ± 0.058 M(ʘ), a radius of R(*)= 1.28(+0.03,-0.03) R(ʘ), an age of 2.92 (+0.80,-0.73) Gyr and solar metallicity, properties consistent with a main-sequence late-F star with T(eff)=6295 ± 77K. We find evidence in the radial velocity measurements of a secondary long-term signal, which could be due to an outer companion. The TOI-677 b system is a well-suited target for Rossiter–Mclaughlin observations that can constrain migration mechanisms of close-in giant planets.
Abstract
TOI-2202 b is a transiting warm Jovian-mass planet with an orbital period of
P
= 11.91 days identified from the Full Frame Images data of five different sectors of the TESS mission. Ten TESS ...transits of TOI-2202 b combined with three follow-up light curves obtained with the CHAT robotic telescope show strong transit timing variations (TTVs) with an amplitude of about 1.2 hr. Radial velocity follow-up with FEROS, HARPS, and PFS confirms the planetary nature of the transiting candidate (
a
b
= 0.096 ± 0.001 au,
m
b
= 0.98 ± 0.06
M
Jup
), and a dynamical analysis of RVs, transit data, and TTVs points to an outer Saturn-mass companion (
a
c
= 0.155 ± 0.002 au,
m
c
= 0.37 ± 0.10
M
Jup
) near the 2:1 mean motion resonance. Our stellar modeling indicates that TOI-2202 is an early K-type star with a mass of 0.82
M
⊙
, a radius of 0.79
R
⊙
, and solar-like metallicity. The TOI-2202 system is very interesting because of the two warm Jovian-mass planets near the 2:1 mean motion resonance, which is a rare configuration, and their formation and dynamical evolution are still not well understood.
Abstract
TOI-216 hosts a pair of warm, large exoplanets discovered by the TESS mission. These planets were found to be in or near the 2:1 resonance, and both of them exhibit transit timing variations ...(TTVs). Precise characterization of the planets’ masses and radii, orbital properties, and resonant behavior can test theories for the origins of planets orbiting close to their stars. Previous characterization of the system using the first six sectors of TESS data suffered from a degeneracy between planet mass and orbital eccentricity. Radial-velocity measurements using HARPS, FEROS, and the Planet Finder Spectrograph break that degeneracy, and an expanded TTV baseline from TESS and an ongoing ground-based transit observing campaign increase the precision of the mass and eccentricity measurements. We determine that TOI-216c is a warm Jupiter, TOI-216b is an eccentric warm Neptune, and that they librate in 2:1 resonance with a moderate libration amplitude of
deg, a small but significant free eccentricity of
for TOI-216b, and a small but significant mutual inclination of 1.°2–3.°9 (95% confidence interval). The libration amplitude, free eccentricity, and mutual inclination imply a disturbance of TOI-216b before or after resonance capture, perhaps by an undetected third planet.
ABSTRACT
HD 21749 is a bright (V = 8.1 mag) K dwarf at 16 pc known to host an inner terrestrial planet HD 21749c as well as an outer sub-Neptune HD 21749b, both delivered by Transiting Exoplanet ...Survey Satellite (TESS). Follow-up spectroscopic observations measured the mass of HD 21749b to be 22.7 ± 2.2 M⊕ with a density of $7.0^{+1.6}_{-1.3}$ g cm−3, making it one of the densest sub-Neptunes. However, the mass measurement was suspected to be influenced by stellar rotation. Here, we present new high-cadence PFS RV data to disentangle the stellar activity signal from the planetary signal. We find that HD 21749 has a similar rotational time-scale as the planet’s orbital period, and the amplitude of the planetary orbital RV signal is estimated to be similar to that of the stellar activity signal. We perform Gaussian process regression on the photometry and RVs from HARPS and PFS to model the stellar activity signal. Our new models reveal that HD 21749b has a radius of 2.86 ± 0.20 R⊕, an orbital period of 35.6133 ± 0.0005 d with a mass of Mb = 20.0 ± 2.7 M⊕ and a density of $4.8^{+2.0}_{-1.4}$ g cm−3 on an eccentric orbit with e = 0.16 ± 0.06, which is consistent with the most recent values published for this system. HD 21749c has an orbital period of 7.7902 ± 0.0006 d, a radius of 1.13 ± 0.10 R⊕, and a 3σ mass upper limit of 3.5 M⊕. Our Monte Carlo simulations confirm that without properly taking stellar activity signals into account, the mass measurement of HD 21749b is likely to arrive at a significantly underestimated error bar.
TESS (Transiting Exoplanet Survey Satellite) was launched in 2018 with the purpose of observing bright stars in the solar neighbourhood to search for transiting exoplanets. After the completion of ...the two year nominal mission, TESS has provided 2\,minute cadence photometry of over 200\,000 stars. This large collection of light curves opens the possibility to study the statistical and temporal properties of this ensemble of stars. Most of the currently available data pipelines are designed to work on single sector at a time. We present a new TESS data pipeline called {\tt Taranga}, with the purpose of merging multi-sector light curves, whilst performing a period search for all the observed stars, and stores the statistical results in a database. {\tt Taranga} pipeline has three components which 1) processes the PDCSAP fluxes of each sector and creates merged PDCSAP light curve, 2) performs a similar operation on the SAP fluxes, and 3) generates the periodograms of the merged SAP and PDCSAP light curves while performing peak identification. For all the 232\,122 stars observed in short cadence in the nominal TESS mission, we provide the merged PDCSAP and SAP light-curves along with their periodograms. We provide a database that has the statistics of all the results produced from {\tt Taranga} of these stars.
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