TESS Archives

Relations between Hα, X-ray, and white-light energies for solar and stellar flares. (left) The relation between Hα and Bolometric X-ray energies (0.1–100 keV = 0.124–124 ˚A). Data of superflares on the G-dwarf EK Dra detected in this study are represented by red squares. Other solar and stellar data are taken from Kawai et al. (2022). The function fitted to the observational data with a power-law is shown by the cyan line. (right) The relation between bolometric white-light and Hα energies. Data of superflares on the G-dwarf EK Dra, which are associated with filament/prominence eruptions, are represented by filled red squares, whereas those without eruptions are represented by open red squares (this study, Namekata et al. 2022d, Namekata et al. 2022c). For E1, the total energy including the blueshift component is plotted as the upper limit, with the radiative energy of the central component from the two-component fit being plotted as the lower limit. Data of M-dwarf flares are taken from Maehara et al. (2021), Namizaki et al. (2023), and (Notsu et al. 2023). Solar flare data are taken from Namekata et al. (2022a). The function fitted to the observational data, excluding flare E1, with a power-law is shown by the cyan line. -- astro-ph.SR

Astronomy & Telescopes, Exoplanets, -moons, -comets, Habitable Zones, Radiation, Space Weather & Heliophysics, Status Report

Multi-wavelength Campaign Observations of a Young Solar-type Star, EK Draconis I. Discovery of Prominence Eruptions Associated with Superflares

by Keith CowingNovember 15, 2023

Young solar-type stars frequently produce superflares, serving as a unique window into the young Sun-Earth environments. Large solar flares are closely linked to coronal mass ejections (CMEs) associated with filament/prominence […]

Mass-radius diagram. The green circles show the exoplanet data from exoplanets.eu, the black stars show the Solar System planets and the blue and orange points show the measured values for TOI-1736 b and TOI-2141 b, respectively. Several models from Zeng et al. (2019) are also plotted for comparison. -- astro-ph.EP

Astronomy & Telescopes, Exoplanets, -moons, -comets, Habitable Zones, Imaging & Spectroscopy, Status Report

TOI-1736 and TOI-2141: Two Systems Including Sub-Neptunes Around Solar Analogs Revealed By TESS And SOPHIE

by Keith CowingNovember 15, 2023November 15, 2023

Planetary systems around solar analogs inform us about how planets form and evolve in Solar System-like environments. We report the detection and characterization of two planetary systems around the solar […]

Best-fit occultation depths of individual CHEOPS visits (blue) along with their posteriors on the right. The horizontal solid and dashed lines represent the mean occultation depth of 82.4 ± 5.6 ppm. The panel on the right-side displays the best-fit posterior distribution. The green shaded regions indicate the span of the TESS Sectors 40, 41 and 54 while the brown points indicate sector-wise occultation depth. -- astro-ph.EP

Astronomy & Telescopes, Exoplanets, -moons, -comets, Imaging & Spectroscopy, Status Report

CHEOPS Observations Of KELT-20 b/MASCARA-2 b: An Aligned Orbit And Signs Of Variability From A Reflective Dayside

by Keith CowingNovember 8, 2023November 8, 2023

Occultations are windows of opportunity to indirectly peek into the dayside atmosphere of exoplanets. High-precision transit events provide information on the spin-orbit alignment of exoplanets around fast-rotating hosts.

Phase-folded light curves of newly validated planetary systems. Dark blue line shows the best-fit model, red dots are binned observations. Gray error bars in the background are data taken from TESS. -- astro-ph.EP

Astronomy & Telescopes, Exoplanets, -moons, -comets, Imaging & Spectroscopy, Status Report

VaTEST III: Validation Of 8 Potential Super-Earths From TESS Data

by Keith CowingNovember 2, 2023November 2, 2023

NASA’s all-sky survey mission, the Transiting Exoplanet Survey Satellite (TESS) is specifically designed to detect transiting exoplanets orbiting bright stars.

Prot vs Porb per spectral type (K-, G-, and F-type stars from top to bottom, left panels). The coloured regions depict the distribution of star-planet occurrences computed with ESPEM, while the blue dots are the CSPHMSS. The grey shaded region indicates the parameter space not covered by the simulation. The dotted and dashed lines are the same as in Fig. 1. The middle and right panels correspond to the Prot histograms and CDFs, respectively, for the three distribution of stars: CSPHMSS (black), ESPEM (red), and RKS (grey). -- astro-ph.EP

Astronomy & Telescopes, Exoplanets, -moons, -comets, Status Report

Stellar Spectral-type (Mass) Dependence Of The Dearth Of Close-in Planets Around Fast-rotating Stars.

by Keith CowingNovember 2, 2023November 2, 2023

In 2013 a dearth of close-in planets around fast-rotating host stars was found using statistical tests on Kepler data. The addition of more Kepler and Transiting Exoplanet Survey Satellite (TESS) […]

Results of Global Climate Model (GCM) simulations of LHS 1140 b assuming an Earth-like atmosphere (1 bar N2, 400 ppm CO2; panels a, c, d, e) and a thick CO2-dominated atmosphere (5 bar CO2; panels b, f, g, h). Panels a, b: Surface temperature maps of LHS 1140 b. The black line indicates the line of stability between liquid water and sea ice. The extent of the ice-free ocean strongly depends on the amount of CO2 in the atmosphere. Panels c, d, e, f, g, and h: Vertical profiles of the atmospheric temperatures, water vapor, and cloud mixing ratios (both H2O and CO2 ice clouds). The solid bold lines indicate the global mean vertical profiles and the dotted lines indicate terminator vertical profiles (impacting transit spectra). -- astro-ph.EP

Astronomy & Telescopes, Exoplanets, -moons, -comets, Imaging & Spectroscopy, Status Report, Water/Hycean Worlds & Oceanography

New Mass and Radius Constraints On The LHS 1140 Planets — LHS 1140 b Is Either A Temperate Mini-Neptune Or A Water World

by Keith CowingOctober 30, 2023October 30, 2023

LHS 1140 b and c are two small temperate exoplanets transiting a nearby M4.5 dwarf. The planetary system was observed with multiple facilities since its discovery in 2017, including MEarth, […]

Mass-radius diagram showing confirmed planets with mass uncertainties < 20% in grey circles, with TOI-544 b shown as the black circle. Left: the coloured tracks show different potential planet compositions from Zeng et al. (2019), assuming a planetary equilibrium temperature of 1000 K. The dashed lines show compositions of an Earth-like rocky core surrounded by a layer of H-He in varying percentages by mass, the solid lines show water world compositions with varying water mass fractions, the dotted lines show rocky and Earth-like rocky compositions. TOI-544 b is closest to the tracks with 100% H2O and 50% H2O with 50% rock. Right: the same as the left panel but the the dashed lines show compositions of an Earth-like rocky core surrounded by a layer of H-He in varying percentages by mass from Lopez & Fortney (2014) using the models for a 10Gyr planet, with solar metalicity and flux of 10F⊕, the solid lines show compositions from Aguichine et al. (2021) of irradiated ocean worlds with varying water mass fractions, and the dotted lines show the same rocky and Earth-like rocky compositions from Zeng et al. (2019). TOI-544 b is closest to models with either 30% water mass fraction, or a rocky core with a Hydrogen envelope of between 0.5 - 1%. The data is downloaded from the NASA Exoplanet Archive. -- astro-ph.EP

Astronomy & Telescopes, Atmospheres, Climate, Weather, Biosignatures & Paleobiology, Exploration Gear & Tech, Habitable Zones, Icy Worlds, Imaging & Spectroscopy, Status Report, Water/Hycean Worlds & Oceanography

TOI-544 b: A Potential Water-world Inside The Radius Valley In A Two-planet System

by Keith CowingOctober 24, 2023October 24, 2023

We report on the precise radial velocity follow-up of TOI-544 (HD 290498), a bright K star (V=10.8), which hosts a small transiting planet recently discovered by the Transiting Exoplanet Survey […]

TESS observations of TOI-904. Panel (a): Raw observations of each TESS sector, with 2-minute data shown in light grey and 10-minute binned data shown in dark grey. We show the Tukey biweight trend calculated with the wotan (Hippke et al. 2019) library of the variability is shown in dark blue. Each planet transit is denoted by an arrow at the bottom of the graph, with blue denoting transits of TOI-904 b and gold denoting transits TOI-904 c. Panel (b): TESS data detrended by the same fit, with each transit high-lighted in the same color as the arrows in the previous figure. Panel (c): The phase folded light curves of transits of TOI-904 b with the transit fit including a shaded region denoting 1σ uncertainty. Panel (d): The phase-folded light curves of TOI-904 c with the transit fit including a shaded region denoting 1σ uncertainty. -- astro-ph.EP

Astronomy & Telescopes, Exoplanets, -moons, -comets, Imaging & Spectroscopy, Status Report

Separated Twins Or Just Siblings? A Multi-planet System Around An M Dwarf Including A Cool sub-Neptune

by Keith CowingOctober 24, 2023October 24, 2023

We report the discovery of two TESS sub-Neptunes orbiting the early M dwarf TOI-904 (TIC 261257684). Both exoplanets, TOI-904 b and c, were initially observed in TESS sector 12 with […]

Individual components of our 3-planet RV model of TOI-1266 and corresponding GLS periodograms. From top to bottom: the raw LBL RVs, stellar RV activity, TOI-1266 b, TOI-1266 c, the planet candidate TOI-1266 d, and the residuals. The residuals do not show any evidence for unaccounted periodicities in the GLS. The vertical shaded regions in the left column highlight each TESS sector’s observing window (annotated at the top) and reveals where we have contemporaneous TESS and spectroscopic observations. Similarly, the vertical dashed lines highlight the epochs of our ground-based transit observations of either TOI-1266 b or c, using the ARCTIC and WIRC cameras. The vertical dashed lines in the right column depict the orbital periods of the transiting TOI-1266 planets, the candidate planet d, and the stellar rotation period inferred from our 𝐻 𝛼 time series. -- astro-ph.EP

Atmospheres, Climate, Weather, Exoplanets, -moons, -comets, Status Report

Masses, Revised Radii, and a Third Planet Candidate in the “Inverted” Planetary System Around TOI-1266

by Keith CowingOctober 24, 2023October 24, 2023

Is the population of close-in planets orbiting M dwarfs sculpted by thermally driven escape or is it a direct outcome of the planet formation process? A number of recent empirical […]

Mass-radius diagram for TOI-1801 b, together with all known exoplanets (grey dots) with a precision better than 8% in radius (through transit) and 20% in mass (from RV). The population of young transiting exoplanets (< 900 Myr) with measured masses is plotted as coloured dots, according to their ages. The uncertainties on TOI-1801 b are shown as coloured shaded regions with 1, 2, and 3σ levels of confidence. In the left panel, the iso-density lines are displayed as dashed grey lines. In the remaining panels where the population of exoplanets is plotted along with TOI-1801 b, coloured lines indicate different composition models without gas (middle panel) and with a gas envelope (right panel) from Zeng et al. (2019). In the right panel, the solid and dotted lines show the models with temperatures of 300 K and 500 K, respectively, of the corresponding specific entropy at 100 bar level in the gas envelope. The Earth and Neptune are also depicted as reference. We include B22 and M22 as references because different results have been published for the same planet, and this refers to Barragán et al. (2022) and El Mufti et al. (2023), respectively. -- astro-ph.EP

Exoplanets, -moons, -comets, Habitable Zones, Status Report

TOI-1801 b: A Temperate Mini-Neptune Around A Young M0.5 Dwarf

by Keith CowingOctober 17, 2023October 17, 2023

We report the discovery, mass, and radius determination of TOI-1801 b, a temperate mini-Neptune around a young M dwarf. TOI-1801 b was observed in TESS sectors 22 and 49, and […]

TESS

Multi-wavelength Campaign Observations of a Young Solar-type Star, EK Draconis I. Discovery of Prominence Eruptions Associated with Superflares

TOI-1736 and TOI-2141: Two Systems Including Sub-Neptunes Around Solar Analogs Revealed By TESS And SOPHIE

CHEOPS Observations Of KELT-20 b/MASCARA-2 b: An Aligned Orbit And Signs Of Variability From A Reflective Dayside

VaTEST III: Validation Of 8 Potential Super-Earths From TESS Data

Stellar Spectral-type (Mass) Dependence Of The Dearth Of Close-in Planets Around Fast-rotating Stars.

New Mass and Radius Constraints On The LHS 1140 Planets — LHS 1140 b Is Either A Temperate Mini-Neptune Or A Water World

TOI-544 b: A Potential Water-world Inside The Radius Valley In A Two-planet System

Separated Twins Or Just Siblings? A Multi-planet System Around An M Dwarf Including A Cool sub-Neptune

Masses, Revised Radii, and a Third Planet Candidate in the “Inverted” Planetary System Around TOI-1266

TOI-1801 b: A Temperate Mini-Neptune Around A Young M0.5 Dwarf

Relevance of the Avalon Assemblage as an Astrobiological Analog for Icy Ocean Worlds

The Climate and Potential Habitability of a Warm and Oxygenated Mars

Variable X-ray flux May Explain Variable Helium Escape From The Habitable-zone Exoplanet LHS 1140b

Spacetime Contactability in Galactic Civilization Networks: Contact Counts and Percolation

Surprisingly Enriched CO and CH4 in Halley-type Comet 13P/Olbers: Clues to Its Interstellar Heritage