TESS News and Results

As noted in the paper, HD 21749 = GJ 143, which has been previously mentioned. This second paper does have a lot more follow-up information in it.

ExoFOP indicates a total of four planet candidates at HD 23472. In addition to the two confirmed planets with periods of 17.6 and 29.8 days, two more planet candidates at 12.17 and 3.98 days may exist, with radii of 2.01 and 1.01 Earth-radii, respectively.

Possibly there are co-orbital planets at TOI-178 in a 3:2:2 resonance, though a 4:3:2 resonance cannot be ruled out. Somewhat reminiscent of KOI-730...

Leleu et al. "Co-orbital exoplanets from close period candidates: The TOI-178 case"
https://arxiv.org/abs/1901.07250

Near-resonance in a system of sub-Neptunes from TESS
https://arxiv.org/abs/1901.09092

Quote :

We report the Transiting Exoplanet Survey Satellite (TESS) detection of a multi-planet system orbiting the V=10.9 K0 dwarf TOI 125. We find evidence for up to five planets, with varying confidence. Three high signal-to-noise transit signals correspond to sub-Neptune-sized planets (2.76, 2.79, and 2.94 R⊕), and we statistically validate the planetary nature of the two inner planets (Pb=4.65 days, Pc=9.15 days). With only two transits observed, we report the outer object (P.03=19.98 days) as a high signal-to-noise ratio planet candidate. We also detect a candidate transiting super-Earth (1.4 R⊕) with an orbital period of only 12.7 hours and a candidate Neptune-sized planet (4.2 R⊕) with a period of 13.28 days, both at low signal-to-noise. This system is amenable to mass determination via radial velocities and transit timing variations, and provides an opportunity to study planets of similar size while controlling for age and environment. The ratio of orbital periods between TOI 125 b and c (Pc/Pb=1.97) is slightly smaller than an exact 2:1 commensurability and is atypical of multiple planet systems from Kepler, which show a preference for period ratios just wide of first-order period ratios. A dynamical analysis refines the allowed parameter space through stability arguments and suggests that, despite the nearly commensurate periods, the system is unlikely to be in resonance.

TOI-125 = TYC 8856-192-1.
Given that the innermost planet has a low SNR, and is significantly misaligned with the rest of the system, it may be more likely that the planet doesn't exist than that it's that badly misaligned.

An Eccentric Massive Jupiter Orbiting a Sub-Giant on a 9.5 Day Period Discovered in the Transiting Exoplanet Survey Satellite Full Frame Images
https://arxiv.org/abs/1901.09950

Quote :

We report the discovery of TOI-172 b from the Transiting Exoplanet Survey Satellite (TESS) mission, a massive hot Jupiter transiting a slightly evolved G-star with a 9.48-day orbital period. This is the first planet to be confirmed from analysis of only the TESS full frame images, because the host star was not chosen as a two minute cadence target. From a global analysis of the TESS photometry and follow-up observations carried out by the TESS follow-up working group, TOI-172 (TIC 29857954) is a slightly evolved star with an effective temperature of Teff =5644±50~K, a mass of M⋆ = 1.124+0.063−0.060 M⊙, radius of R⋆ = 1.774+0.046−0.043 R⊙, a surface gravity of log g⋆ = 3.993+0.026−0.027, and an age of 7.5+1.6−1.4 Gyr. Its planetary companion (TOI-172 b) has a radius of RP = 0.965+0.033−0.030 RJ, a mass of MP = 5.41+0.21−0.20 MJ, and is on an eccentric orbit (e = 0.3805+0.0092−0.0090). TOI-172 b is one of the few known massive giant planets on a highly eccentric short-period orbit. Future study of the atmosphere of this planet and its system architecture offer opportunities to understand the formation and evolution of similar systems.

TOI-172 = TYC 6932-301-1

A resonant pair of warm giant planets revealed by TESS
https://arxiv.org/abs/1902.03900

Quote :

We present the discovery of a pair of transiting giant planets, TOI-216b and c, using four sectors of TESS photometry. TOI-216 is a 0.87M⊙ dwarf orbited by two transiters with radii of 8.2R⊕ and 11.3R⊕, and periods of 17.01d and 34.57d, respectively. Anti-correlated TTVs are clearly evident indicating that the transiters orbit the same star and interact via a near 2:1 mean motion resonance. By fitting the TTVs with a dynamical model, we infer masses of 26+24−11M⊕ and 190+220−80M⊕, establishing that the objects are planetary in nature and have sub-Kronian and Kronian densities. TOI-216 lies close to the southern ecliptic pole and thus will be observed by TESS throughout the first year, providing an opportunity for continuous dynamical monitoring and considerable refinement of the dynamical masses presented here. TOI-216 closely resembles Kepler-9 in architecture, and we hypothesize that in such systems these Saturn-analogs failed to fully open a gap and thus migrated far deeper into the system before becoming trapped into resonance, which would imply that future detections of new analogs may also have sub-Jupiter masses.

abstract : "sub-Kronian and Kronian densities" : what does it mean ? it's about Saturn satellites ?

Kronos is the Greek god equivalent of Saturn. "sub-Kronian" can be read as "sub-Saturnian."
Not sure why they were trying to be clever with it.

TOI-150: A transiting hot Jupiter in the TESS southern CVZ
https://arxiv.org/abs/1902.09710

Quote :

We report the detection of a hot Jupiter (Mp=1.72±0.09 MJ, Rp=1.38±0.04 RJ) orbiting a middle-aged star (logg=4.152+0.030−0.043) in the TESS southern continuous viewing zone (β=−79.59∘). We confirm the planetary nature of the candidate TOI-150.01 using radial velocity observations from the APOGEE-2 South spectrograph and the Carnegie Planet Finder Spectrograph, ground-based photometric observations from the robotic Three-hundred MilliMeter Telescope at Las Campanas Observatory, and Gaia distance estimates. Large scale spectroscopic surveys, such as APOGEE/APOGEE-2, now have sufficient radial velocity precision to directly confirm the signature of giant exoplanets, making such data sets valuable tools in the TESS-era. Continual monitoring of TOI-150 by TESS can reveal additional planets and subsequent observations can provide insights into planetary system architectures involving a hot Jupiter around a star about halfway through its main-sequence life.

TOI-150 = TYC 9191-519-1.

A hot rocky and a warm puffy super-Earth orbiting TOI-402 (HD 15337)
https://arxiv.org/abs/1903.05419

The HD 15337 transiting system: a pair of sub-Neptune-mass planets on the opposite sides of the radius gap
https://arxiv.org/abs/1903.05623

A Super-Earth and two sub-Neptunes transiting the bright, nearby, and quiet M-dwarf TOI-270
https://arxiv.org/abs/1903.06107

Quote :

We report the Transiting Exoplanet Survey Satellite (TESS) discovery of three small planets transiting one of the brightest (K-mag 8.3) and nearest (22.5 parsec) M-dwarf hosts to date, TOI-270 (TIC 259377017). The system is observationally favourable, and can be exceptionally well characterised over the next few years. The M3V-type star is transited by the Super-Earth-sized TOI-270b (1.25 Rearth) and the sub-Neptune-sized exoplanets TOI-270 c (2.42 Rearth) and TOI-270 d (2.13 Rearth). The planet configuration is close to a mean-motion resonant chain, with the orbital periods (3.36, 5.66, and 11.38 days) near ratios of small integers (5:3 and 2:1). Notably, the equilibrium temperature of the outer planet (340 K) lies within the survivable range for extremophile organisms. TOI-270 will be a prime target for future studies since: 1) its near-resonance allows the detection of transit timing variations (TTVs) for precise mass measurements and detailed dynamical studies; 2) its brightness enables independent radial velocity (RV) mass measurements; 3) the outer planets are ideal for atmospheric characterisation via transmission spectroscopy with the James Webb Space Telescope (JWST); and 4) the quiet host star is well suited for future searches of terrestrial planets within the habitable zone. Altogether, very few systems with temperate small exoplanets are as suitable for complementary characterisation by TTVs, RVs and transmission spectroscopy as TOI-270.

HD 213885b: A transiting 1-day-period super-Earth with an Earth-like composition around a bright (V=7.9) star unveiled by TESS
https://arxiv.org/abs/1903.07694

The L 98-59 System: Three Transiting, Terrestrial-Sized Planets Orbiting a Nearby M-dwarf
https://arxiv.org/abs/1903.08017

A transiting exocomet detected in broadband light by TESS in the β Pictoris system
https://arxiv.org/abs/1903.11071

TESS Delivers Its First Earth-sized Planet and a Warm Sub-Neptune
https://iopscience.iop.org/article/10.3847/2041-8213/ab12ed/meta

Quote :

The future of exoplanet science is bright, as Transiting Exoplanet Survey Satellite (TESS) once again demonstrates with the discovery of its longest-period confirmed planet to date. We hereby present HD 21749b (TOI 186.01), a sub-Neptune in a 36 day orbit around a bright (V = 8.1) nearby (16 pc) K4.5 dwarf. TESS measures HD 21749b to be ${2.61}_{-0.16}^{+0.17}$ R ⊕, and combined archival and follow-up precision radial velocity data put the mass of the planet at ${22.7}_{-1.9}^{+2.2}$ M ⊕. HD 21749b contributes to the TESS Level 1 Science Requirement of providing 50 transiting planets smaller than 4 R ⊕ with measured masses. Furthermore, we report the discovery of HD 21749c (TOI 186.02), the first Earth-sized (${R}_{p}={0.892}_{-0.058}^{+0.064}{R}_{\oplus }$) planet from TESS. The HD 21749 system is a prime target for comparative studies of planetary composition and architecture in multi-planet systems.

This is the same system reported as GJ 143 by Trifonov et al.

TOI-216b and TOI-216c: Two warm, large exoplanets in or slightly wide of the 2:1 orbital resonance
https://arxiv.org/abs/1904.11852

Quote :

Warm, large exoplanets with 10-100 day orbital periods pose a major challenge to our understanding of how planetary systems form and evolve. Although high eccentricity tidal migration has been invoked to explain their proximity to their host stars, a handful reside in or near orbital resonance with nearby planets, suggesting a gentler history of in situ formation or disk migration. Here we confirm and characterize a pair of warm, large exoplanets discovered by the TESS Mission orbiting K-dwarf TOI-216. Our analysis includes additional transits and transit exclusion windows observed via ground-based follow-up. We find two families of solutions, one corresponding to a sub-Saturn-mass planet accompanied by a Neptune-mass planet and the other to a Jupiter in resonance with a sub-Saturn-mass planet. We prefer the second solution based on the orbital period ratio, the planet radii, the lower free eccentricities, and libration of the 2:1 resonant argument, but cannot rule out the first. The free eccentricities and mutual inclination are compatible with stirring by other, undetected planets in the system, particularly for the second solution. We discuss prospects for better constraints on the planets' properties and orbits through follow-up, including transits observed from the ground.

TESS Spots a Compact System of Super-Earths around the Naked-Eye Star HR 858
https://arxiv.org/abs/1905.05193

Quote :

Transiting Exoplanet Survey Satellite (TESS) observations have revealed a compact multi-planet system around the sixth-magnitude star HR 858 (TIC 178155732), located 32 parsecs away. Three planets, each about twice the size of Earth, transit this slightly-evolved, late F-type star, which is also a member of a visual binary. Two of the planets may be in mean motion resonance. We analyze the TESS observations, using novel methods to model and remove instrumental systematic errors, and combine these data with follow-up observations taken from a suite of ground-based telescopes to characterize the planetary system. The HR 858 planets are enticing targets for precise radial velocity observations, secondary eclipse spectroscopy, and measurements of the Rossiter-McLaughlin effect.

Sirius_Alpha wrote:

A transiting exocomet detected in broadband light by TESS in the β Pictoris system
https://arxiv.org/abs/1903.11071

https://www.uibk.ac.at/public-relations/presse/archiv/2019/1149/

Three exocomets discovered around the star Beta Pictoris

Three extrasolar comets have been discovered around the star Beta Pictoris, 63 light years away, by the University of Innsbruck. Analysis of data from the current NASA mission TESS by Sebastian Zieba and Konstanze Zwintz from the Institute for Astro- and Particle Physics, together with colleagues from Leiden University (Netherlands) and the University of Warwick (UK) has revealed the objects for the first time using TESS data.

A super-Earth and sub-Neptune transiting the late-type M dwarf LP 791-18
https://arxiv.org/abs/1906.09267

TOI-150b and TOI-163b: two transiting hot Jupiters, one eccentric and one inflated, revealed by TESS near and at the edge of the JWST CVZ
https://arxiv.org/abs/1906.09866

Evidence for additional planets from TTVs at WASP-18, WASP-126 and TOI-193.

Evidence for 3 new multi-planet systems from TESS using a Bayesian N-body retrieval and machine learning
https://arxiv.org/abs/1907.03377

TESS gets a mission extension through 2022.

https://science.nasa.gov/astrophysics/2019-senior-review-operating-missions

Transit timing variations for WASP-4

Southworth et al. "Transit timing variations in the WASP-4 planetary system"
https://arxiv.org/abs/1907.08269

This may be due to apsidal motion. Orbital decay, the Applegate mechanism and light travel time effects do not appear to be consistent with the observations.

Sirius_Alpha wrote:

A Super-Earth and two sub-Neptunes transiting the bright, nearby, and quiet M-dwarf TOI-270
https://arxiv.org/abs/1903.06107

NASA press release :

https://www.nasa.gov/feature/goddard/2019/nasa-s-tess-mission-scores-hat-trick-with-3-new-worlds

NASA’s TESS Mission Scores ‘Hat Trick’ With 3 New Worlds
NASA’s newest planet hunter, the Transiting Exoplanet Survey Satellite (TESS), has discovered three new worlds — one slightly larger than Earth and two of a type not found in our solar system — orbiting a nearby star. The planets straddle an observed gap in the sizes of known planets and promise to be among the most curious targets for future studies.
TESS Object of Interest (TOI) 270 is a faint, cool star more commonly identified by its catalog name: UCAC4 191-004642. The M-type dwarf star is about 40% smaller than the Sun in both size and mass, and it has a surface temperature about one-third cooler than the Sun’s. The planetary system lies about 73 light-years away in the southern constellation of Pictor.

TESS has found the first-ever ‘ultrahot Neptune’
https://www.sciencenews.org/article/nasa-tess-first-ultrahot-neptune-exoplanet

Quote :

Astronomers have spotted a new kind of planet: a Neptune-sized world sitting scorchingly close to its star. It could be in the midst of transforming from a hot, puffy gas giant to a naked rocky core, astronomer James Jenkins reported July 29 at the TESS Science Conference at MIT.

Quote :

Most other planets with such close orbits are either Earth-sized or Jupiter-sized and larger, said Jenkins, of the University of Chile in Santiago. But LTT 9779b is 4.6 times Earth’s size and 29.3 times Earth’s mass, placing it right in the middle of those extremes. Its proximity to its star should heat it to about 2000 kelvins (about 1725° Celsius), making it the first known ultrahot Neptune, Jenkins said.

Listed in EPE also as TOI-193 b:

http://exoplanet.eu/catalog/ltt_9779_b/

GJ 357, a nearby M dwarf with three planets.

PR YouTube video
https://www.youtube.com/watch?v=6bWra2Wvudk

Press Release
"TESS Mission Helps Uncover Trio Of Planets With One Possibly Habitable World"
https://carnegiescience.edu/news/tess-mission-helps-uncover-trio-planets-one-possibly-habitable-world?fbclid=IwAR1kOrD2_ZhdaNL7i7dbY0ERvxY1UayfbOAX2MP4TwR1kxEuODv-CwqmTdc

Of course the planet near the HZ has a minimum mass of ~6 earth-masses. So the "possibly habitable" line is used ... a bit loosely.