TESS Archives - Page 30 of 33 - Astrobiology

Distribution of injected signals and signals recovered by the UCLA SETI pipeline as a function of frequency. Blue bands indicated the operating bands of GPS and GLONASS satellites, where recovery rates are markedly lower. Frequencies corresponding to a notch filter at the GBT (1.2 – 1.3412 GHz) are excluded. -- astro-ph.IM

Astronomy & Telescopes, SETI & Technosignatures, Status Report

A Search For Technosignatures Around 11,680 Stars With The Green Bank Telescope At 1.15-1.73 GHz

by Keith CowingAugust 9, 2023August 9, 2023

We conducted a search for narrowband radio signals over four observing sessions in 2020-2023 with the L-band receiver (1.15-1.73 GHz) of the 100 m diameter Green Bank Telescope.

Periodogram analysis for Gaussian noise and a smaller planet with injected transit depth 68 ppm. See Figure 1 for a description of the panels -- astro-ph.EP

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

TCF Periodogram’s High Sensitivity: A Method For Optimizing Detection Of Small Transiting Planets

by Keith CowingAugust 9, 2023August 9, 2023

We conduct a methodological study for statistically comparing the sensitivities of two periodograms for weak signal planet detection in transit surveys: the widely used Box-Least Squares (BLS) algorithm following light […]

This artist's illustration shows a planet (dark silhouette) passing in front of the red dwarf star AU Microscopii. The planet is so close to the eruptive star a ferocious blast of stellar wind and blistering ultraviolet radiation is heating the planet's hydrogen atmosphere, causing it to escape into space. Four times Earth's diameter, the planet is slowly evaporating its atmosphere, which stretches out linearly along its orbital path. This process may eventually leave behind a rocky core. The illustration is based on measurements made by the Hubble Space Telescope. Credits: NASA, ESA, and Joseph Olmsted (STScI)

Astronomy & Telescopes, Atmospheres, Climate, Weather, Exoplanets, -moons, -comets, Habitable Zones, Press Release, Space Weather & Heliophysics

A Young Super-Earth Orbiting Red Dwarf AU Microscopii Is Evaporating

by Keith CowingJuly 29, 2023July 29, 2023

A young planet whirling around a petulant red dwarf star is changing in unpredictable ways orbit-by-orbit. It is so close to its parent star that it experiences a consistent, torrential […]

PDCSAP flux extracted from the short (2 minute) cadence data of the 24 sectors (1–13, 27, 29–37, 39) in which TOI-715 was observed. Light grey point show the 120 s exposures and the purple line shows the flux in 3minute bins. The transit events of TOI-715.01 are shown with the dark pink arrows and the locations of possible transits of TIC 271971130.02 are indicated with green arrows; we note that individual transits are not readily apparent by eye. -- astro-ph.EP

Astronomy & Telescopes, Atmospheres, Climate, Weather, Biosignatures & Paleobiology, Exoplanets, -moons, -comets, Habitable Zones, Status Report

A 1.55 R⊕ Habitable-zone Planet Hosted By TOI-715, An M4 Star Near The Ecliptic South Pole

by Keith CowingJuly 8, 2023July 8, 2023

A new generation of observatories is enabling detailed study of exoplanetary atmospheres and the diversity of alien climates, allowing us to seek evidence for extraterrestrial biological and geological processes.

The phased light curve of LTT 1445A, highlighting the transit of planet c. The detrended TESS observations are show in black and our new HST observations in orange. In blue, we show our MAP orbital solution. -- astro-ph.EP

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

HST/WFC3 Light Curve Confirms the Closest Exoplanet to Transit an M Dwarf is Terrestrial

by Keith CowingJuly 7, 2023July 7, 2023

Previous studies of the exoplanet LTT 1445Ac concluded that the light curve from the Transiting Exoplanet Survey Satellite (TESS) was consistent with both grazing and non-grazing geometries. As a result, […]

The mass-radius diagram for small planets. Data comes from the NASA Exoplanet Archive’s planetary systems table, as accessed on 2022-Nov-17 (NASA Exoplanet Archive 2022). Planets with mass and radius measurements to better than 50% and 15% fractional precision, respectively, are shown as the circles with 1σ error bars. The opacity of the points is proportional to mass measurement precision (i.e., a less precise mass measurement translates to a more transparent marker). Color corresponds to equilibrium temperature assuming zero Bond albedo and full day-night heat redistribution. Underlying contours come from Gaussian kernel density estimation (KDE) of the confirmed planets described above. The 11 transiting planets from this work are overplotted as the stars. Mass upper limits (98% confidence) are plotted for HD 25463 c (yellow star near the radius valley) and HIP 9618 c (labeled). A handful of composition curves are plotted for reference (Lopez & Fortney 2014; Zeng et al. 2016, 2019). The curves of H/He envelopes atop Earth-like cores come from Lopez & Fortney (2014) and are chosen for a planet receiving 10× Earth’s incident flux (i.e., Teq ≈ 500 K) orbiting a 10 Gyr-old, solar-metallicity star. The 50% water plus 50% Earth-like composition curve from Zeng et al. (2019) is calculated for a fixed temperature of 700 K at 100 bar, which determines the planetary model’s specific entropy. Note that familiar features of the planet radius distribution are now visible as two-dimensional features in the mass-radius plane. These include the radius valley (Fulton et al. 2017; Van Eylen et al. 2018), with center near 6 M⊕ and 1.8 R⊕, and the radius cliff (e.g., Kite et al. 2019), as seen by in the steep drop off in the number of planets around 3 R⊕. -- astro-ph.EP

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

The TESS-Keck Survey. XVI. Mass Measurements for 12 Planets in Eight Systems

by Keith CowingJune 29, 2023June 29, 2023

With JWST’s successful deployment and unexpectedly high fuel reserves, measuring the masses of sub-Neptunes transiting bright, nearby stars will soon become the bottleneck for characterizing the atmospheres of small exoplanets […]

TESS target pixel file images of TOI-2084 observed in Sector 16 (left panel) and TOI-4184 observed in Sector 1 (right panel), made by tpfplotter (Aller et al. 2020). Red dots show the location of Gaia DR3 sources, and the red shaded region shows the photometric apertures used to extract the photometric measurements. -- astro-ph.EP

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

TOI-2084 b and TOI-4184 b: Two New Sub-Neptunes Around M Dwarf Stars

by Keith CowingJune 28, 2023June 28, 2023

We present the discovery and validation of two TESS exoplanets orbiting nearby M dwarfs: TOI-2084b, and TOI-4184b. We characterized the host stars by combining spectra from Shane/Kast and Magellan/FIRE, SED […]

The result of the transit injection-and-recovery test for the planet candidate. Blue to light green represents an increasing detection possibility of its transit signal (assuming it transits). The solid blue histogram in the top panel illustrates the average number of transits within the TESS time baseline. The foreground yellow solid lines mark the six possible orbital solutions of the planet candidate found in Juliet. -- astro-ph.EP

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

A Transiting Super-Earth in the Radius Valley and An Outer Planet Candidate Around HD 307842

by Keith CowingJune 26, 2023June 26, 2023

We report the confirmation of a TESS-discovered transiting super-Earth planet orbiting a mid-G star, HD 307842 (TOI-784). The planet has a period of 2.8 days, and the radial velocity (RV) […]

Target Pixel File (TPF) from TESS sector 1 with TOI-908 marked with a white cross. Other sources from Gaia DR2 are marked with red circles sized by scaled magnitudes relative to the target, ranked by distance. The aperture mask is indicated by the red outline. -- astro-ph.EP

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

TOI-908: A Planet At The Edge Of The Neptune Desert Transiting A G-type Star

by Keith CowingJune 19, 2023June 19, 2023

We present the discovery of an exoplanet transiting TOI-908 (TIC-350153977) using data from TESS sectors 1, 12, 13, 27, 28 and 39. TOI-908 is a T = 10.7 mag G-dwarf […]

Observed and best-fit model light-curves (one transit event) for KELT-2 A b, KELT-3 b, KELT-4 A b and KELT-11 b. For each observed transit, Top: the unprocessed light-curve (cyan), light-curve after wavelet denoising (magenta), the best-fit transit model (blue). Middle: the residual after modeling without GP regression (magenta), the mean (blue) and 1-σ interval (cyan) of the best-fit GP regression model. Bottom: mean residual flux (blue). -- astro-ph.EP

Astronomy & Telescopes, Atmospheres, Climate, Weather, Biosignatures & Paleobiology, Habitable Zones, Imaging & Spectroscopy, Status Report

Precise Transit Photometry Using TESS: Updated Physical Properties for 28 Exoplanets Around Bright Stars

by Keith CowingJune 5, 2023June 5, 2023

The TESS follow-up of a large number of known transiting exoplanets provide unique opportunity to study their physical properties more precisely.