TESS Photometry Research Articles

K2, Spitzer, and TESS Transits of Four Sub-Neptune Exoplanets

Abstract We present new Spitzer transit observations of four K2 transiting sub-Neptunes: K2-36 c, K2-79b, K2-167b, and K2-212b. We derive updated orbital ephemerides and radii for these planets based on a joint analysis of the Spitzer, TESS, and K2 photometry. We use the EVEREST pipeline to provide improved K2 photometry, by detrending instrumental noise and K2's pointing jitter. We used a pixel-level decorrelation method on the Spitzer observations to reduce instrumental systematic effects. We modeled the effect of possible blended eclipsing binaries, seeking to validate these planets via the achromaticity of the transits (K2 versus Spitzer). However, we find that Spitzer’s signal-to-noise ratio for these small planets is insufficient to validate them via achromaticity. Nevertheless, by jointly fitting radii between K2 and Spitzer observations, we were able to independently confirm the K2 radius measurements. Due to the long time baseline between the K2 and Spitzer observations, we were also able to increase the precision of the orbital periods compared to K2 observations alone. The improvement is a factor of 3 for K2-36 c, and more than an order of magnitude for the remaining planets. Considering possible JWST observations in 1/2023, previous 1σ uncertainties in transit times for these planets range from 74–434 minutes, but we have reduced them to the range of 8–23 minutes.

Discovery of a young pre-intermediate polar

ABSTRACT We present the discovery of a magnetic field on the white dwarf component in the detached post-common envelope binary (PCEB) CC Cet. Magnetic white dwarfs in detached PCEBs are extremely rare, in contrast to the high incidence of magnetism in single white dwarfs and cataclysmic variables. We find Zeeman-split absorption lines in both ultraviolet Hubble Space Telescope (HST) spectra and archival optical spectra of CC Cet. Model fits to the lines return a mean magnetic field strength of 〈|B|〉 ≈ 600–700 kG. Differences in the best-fitting magnetic field strength between two separate HST observations and the high $v\, \sin \, i$ of the lines indicate that the white dwarf is rotating with a period ∼0.5 h, and that the magnetic field is not axisymmetric about the spin axis. The magnetic field strength and rotation period are consistent with those observed among the intermediate polar class of cataclysmic variable, and we compute stellar evolution models that predict CC Cet will evolve into an intermediate polar in 7–17 Gyr. Among the small number of known PCEBs containing a confirmed magnetic white dwarf, CC Cet is the hottest (and thus youngest), with the weakest field strength, and cannot have formed via the recently proposed crystallization/spin-up scenario. In addition to the magnetic field measurements, we update the atmospheric parameters of the CC Cet white dwarf via model spectra fits to the HST data and provide a refined orbital period and ephemeris from TESS photometry.

An all-sky sample of intermediate- to high-mass OBA-type eclipsing binaries observed by TESS

Context.Intermediate- to high-mass stars are the least numerous types of stars, and they are less well understood than their more numerous low-mass counterparts in terms of their internal physical processes. Modelling the photometric variability of a large sample of main-sequence intermediate- to high-mass stars in eclipsing binary systems will help to improve the models for such stars.Aims.Our goal is to compose a homogeneously compiled sample of main-sequence intermediate- to high-mass OBA-type dwarfs in eclipsing binary systems from TESS photometry. We search for binaries with and without pulsations and determine their approximate ephemerides.Methods.Our selection starts from a catalogue of dwarfs with colours corresponding to those of OBA-type dwarfs in the TESS Input Catalog. We develop a new automated method aimed at detecting eclipsing binaries in the presence of a strong pulsational and/or rotational signal relative to the eclipse depths and apply it to publicly available 30-min cadence TESS light curves.Results.Using targets with TESS magnitudes below 15 and cuts in the 2MASS magnitude bands ofJ − H < 0.045 andJ − K < 0.06 as the most stringent criteria, we arrive at a total of 189 981 intermediate- to high-mass candidates, 91 193 of which have light curves from at least one of two data reduction pipelines. The eclipsing binary detection and subsequent manual check for false positives resulted in 3155 unique OBA-type eclipsing binary candidates.Conclusions.Our sample of eclipsing binary stars in the intermediate- to high-mass regime allows for future binary (and asteroseismic) modelling with the aim to better understand the internal physical processes in this hot part of the main sequence.

Recurring Planetary Debris Transits and Circumstellar Gas around White Dwarf ZTF J0328–1219

Abstract We present follow-up photometry and spectroscopy of ZTF J0328−1219, strengthening its status as a white dwarf exhibiting transiting planetary debris. Using TESS and Zwicky Transient Facility photometry, along with follow-up high-speed photometry from various observatories, we find evidence for two significant periods of variability at 9.937 and 11.2 hr. We interpret these as most likely the orbital periods of different debris clumps. Changes in the detailed dip structures within the light curves are observed on nightly, weekly, and monthly timescales, reminiscent of the dynamic behavior observed in the first white dwarf discovered to harbor a disintegrating asteroid, WD 1145+017. We fit previously published spectroscopy along with broadband photometry to obtain new atmospheric parameters for the white dwarf, with M ⋆ = 0.731 ± 0.023 M ⊙, T eff = 7630 ± 140 K, and [Ca/He] = − 9.55 ± 0.12. With new high-resolution spectroscopy, we detect prominent and narrow Na D absorption features likely of circumstellar origin, with velocities 21.4 ± 1.0 km s−1 blueshifted relative to atmospheric lines. We attribute the periodically modulated photometric signal to dusty effluents from small orbiting bodies such as asteroids or comets, but we are unable to identify the most likely material that is being sublimated, or otherwise ejected, as the environmental temperatures range from roughly 400 to 700 K.

Temperature and Distance Dependence of Tidal Circularization in Close Binaries: A Catalog of Eclipsing Binaries in the Southern Hemisphere Observed by the TESS Satellite

Abstract Tidal forces are important for understanding how close binary stars and compact exoplanetary systems form and evolve. However, tides are difficult to model, and significant uncertainties exist about the strength of tides. Here, we investigate tidal circularization in close binaries using a large sample of well-characterized eclipsing systems. We searched TESS photometry from the southern hemisphere for eclipsing binaries. We derive best-fit orbital and stellar parameters by jointly modeling light curves and spectral energy distributions. To determine the eccentricity distribution of eclipsing binaries over a wide range of stellar temperatures (3000–50,000 K) and orbital separations a/R 1 (2–300), we combine our newly obtained TESS sample with eclipsing binaries observed from the ground and by the Kepler mission. We find a clear dependency of stellar temperature and orbital separation in the eccentricities of close binaries. We compare our observations with predictions of the equilibrium and dynamical tides. We find that while cool binaries agree with the predictions of the equilibrium tide, a large fraction of binaries with temperatures between 6250 K and 10,000 K and orbital separations between a/R 1 ∼ 4 and 10 are found on circular orbits, contrary to the predictions of the dynamical tide. This suggests that some binaries with radiative envelopes may be tidally circularized significantly more efficiently than usually assumed. Our findings on orbital circularization have important implications also in the context of hot Jupiters, where tides have been invoked to explain the observed difference in the spin–orbit alignment between hot and cool host stars.

Re-crowning The Queen: Membership, Age, and Rotation Periods for the Open Cluster Coma Berenices

Abstract Coma Berenices (Coma Ber), an open cluster about the same age as Praesepe and the Hyades (700–800 Myr) is, despite being only 85 pc away, less well studied than its famous cousins. This is due principally to its sparseness and low proper motion, which together made Coma Ber’s membership challenging to establish pre-Gaia. We have curated a new list of its members based on Gaia DR2 astrometry, derived its metallicity and interstellar reddening using LAMOST data, and inferred the cluster’s age by fitting PARSEC isochrones to its color–magnitude diagram. We then measured rotation periods for Coma Ber’s low-mass members using TESS and ZTF photometry. Our isochrone fitting and the TESS- and ZTF-derived rotation periods confirm that Coma Ber is coeval with the Hyades and Praesepe. This work is the first step toward re-establishing Coma Ber as another valuable benchmark cluster for age–rotation–activity studies.

A sub-Neptune and a non-transiting Neptune-mass companion unveiled by ESPRESSO around the bright late-F dwarf HD 5278 (TOI-130)

Context. Transiting sub-Neptune-type planets, with radii approximately between 2 and 4 R⊕, are of particular interest as their study allows us to gain insight into the formation and evolution of a class of planets that are not found in our Solar System. Aims. We exploit the extreme radial velocity (RV) precision of the ultra-stable echelle spectrograph ESPRESSO on the VLT to unveil the physical properties of the transiting sub-Neptune TOI-130 b, uncovered by the TESS mission orbiting the nearby, bright, late F-type star HD 5278 (TOI-130) with a period of Pb = 14.3 days. Methods. We used 43 ESPRESSO high-resolution spectra and broad-band photometry information to derive accurate stellar atmospheric and physical parameters of HD 5278. We exploited the TESS light curve and spectroscopic diagnostics to gauge the impact of stellar activity on the ESPRESSO RVs. We performed separate as well as joint analyses of the TESS photometry and the ESPRESSO RVs using fully Bayesian frameworks to determine the system parameters. Results. Based on the ESPRESSO spectra, the updated stellar parameters of HD 5278 are Teff = 6203 ± 64 K, log g = 4.50 ± 0.11 dex, [Fe/H] = −0.12 ± 0.04 dex, M⋆ = 1.126−0.035+0.036 M⊙, and R⋆ = 1.194−0.016+0.017 R⊙. We determine HD 5278 b’s mass and radius to be Mb = 7.8−1.4+1.5 M⊕ and Rb = 2.45 ± 0.05R⊕. The derived mean density, ϱb = 2.9−0.5+0.6 g cm−3, is consistent with the bulk composition of a sub-Neptune with a substantial (~ 30%) water mass fraction and with a gas envelope comprising ~17% of the measured radius. Given the host brightness and irradiation levels, HD 5278 b is one of the best targetsorbiting G-F primaries for follow-up atmospheric characterization measurements with HST and JWST. We discover a second, non-transiting companion in the system, with a period of Pc = 40.87−0.17+0.18 days and a minimum mass of Mc sin ic = 18.4−1.9+1.8 M⊕. We study emerging trends in parameters space (e.g., mass, radius, stellar insolation, and mean density) of the growing population of transiting sub-Neptunes, and provide statistical evidence for a low occurrence of close-in, 10 − 15M⊕ companions around G-F primaries with Teff ≳ 5500 K.

Phase curve and variability analysis of WASP-12b using TESS photometry

ABSTRACT We analyse Sector 20 TESS photometry of the ultra-hot Jupiter WASP-12b, and extract its phase curve to study the planet’s atmospheric properties. We successfully recover the phase curve with an amplitude of 549 ± 62 ppm, and a secondary eclipse depth of 609$^{+74}_{-73}$ ppm. The peak of the phase curve is shifted by 0.049 ± 0.015 in phase, implying that the brightest spot in the atmosphere is shifted from the substellar point towards the planet’s evening terminator. Assuming zero albedo, the eclipse depth infers a day-side brightness temperature of 3128$^{+64}_{-68}$ K. No significant detection of flux from the night-side is found at 60 ± 97 ppm, implying a night-side brightness temperature of <2529 K (1-σ). We do not detect any significant variability in the light from the planet over the ∼27 d of the TESS observations. Finally, we note that an ephemeris model taking orbital decay into account provides a significantly better fit than a constant-period model.

A hot mini-Neptune in the radius valley orbiting solar analogue HD 110113

ABSTRACT We report the discovery of HD 110113 b (TESS object of interest-755.01), a transiting mini-Neptune exoplanet on a 2.5-d orbit around the solar-analogue HD 110113 (Teff = 5730 K). Using TESS photometry and High Accuracy Radial velocity Planet Searcher (HARPS) radial velocities gathered by the NCORES program, we find that HD 110113 b has a radius of 2.05 ± 0.12 R⊕ and a mass of 4.55 ± 0.62 M⊕. The resulting density of $2.90^{+0.75}_{-0.59}$ g cm−3 is significantly lower than would be expected from a pure-rock world; therefore HD 110113 b must be a mini-Neptune with a significant volatile atmosphere. The high incident flux places it within the so-called radius valley; however, HD 110113 b was able to hold on to a substantial (0.1–1 per cent) H–He atmosphere over its ∼4 Gyr lifetime. Through a novel simultaneous Gaussian process fit to multiple activity indicators, we were also able to fit for the strong stellar rotation signal with period 20.8 ± 1.2 d from the RVs and confirm an additional non-transiting planet, HD 110113 c, which has a mass of 10.5 ± 1.2 M⊕ and a period of $6.744^{+0.008}_{-0.009}$ d.

HD 76920 b pinned down: A detailed analysis of the most eccentric planetary system around an evolved star

Abstract We present 63 new multi-site radial velocity (RV) measurements of the K1III giant HD 76920, which was recently reported to host the most eccentric planet known to orbit an evolved star. We focused our observational efforts on the time around the predicted periastron passage and achieved near-continuous phase coverage of the corresponding RV peak. By combining our RV measurements from four different instruments with previously published ones, we confirm the highly eccentric nature of the system and find an even higher eccentricity of $e=0.8782 \pm 0.0025$ , an orbital period of $415.891^{+0.043}_{-0.039}\,\textrm{d}$ , and a minimum mass of $3.13^{+0.41}_{-0.43}\,\textrm{M}_{\textrm{J}}$ for the planet. The uncertainties in the orbital elements are greatly reduced, especially for the period and eccentricity. We also performed a detailed spectroscopic analysis to derive atmospheric stellar parameters, and thus the fundamental stellar parameters ( $M_*, R_*, L_*$ ), taking into account the parallax from Gaia DR2, and independently determined the stellar mass and radius using asteroseismology. Intriguingly, at periastron, the planet comes to within 2.4 stellar radii of its host star’s surface. However, we find that the planet is not currently experiencing any significant orbital decay and will not be engulfed by the stellar envelope for at least another 50–80 Myr. Finally, while we calculate a relatively high transit probability of 16%, we did not detect a transit in the TESS photometry.

An unusually low density ultra-short period super-Earth and three mini-Neptunes around the old star TOI-561

ABSTRACT Based on HARPS-N radial velocities (RVs) and TESS photometry, we present a full characterization of the planetary system orbiting the late G dwarf TOI-561. After the identification of three transiting candidates by TESS, we discovered two additional external planets from RV analysis. RVs cannot confirm the outer TESS transiting candidate, which would also make the system dynamically unstable. We demonstrate that the two transits initially associated with this candidate are instead due to single transits of the two planets discovered using RVs. The four planets orbiting TOI-561 include an ultra-short period (USP) super-Earth (TOI-561 b) with period Pb = 0.45 d, mass Mb = 1.59 ± 0.36 M⊕ and radius Rb = 1.42 ± 0.07 R⊕, and three mini-Neptunes: TOI-561 c, with Pc = 10.78 d, Mc = 5.40 ± 0.98 M⊕, Rc = 2.88 ± 0.09 R⊕; TOI-561 d, with Pd = 25.6 d, Md = 11.9 ± 1.3 M⊕, Rd = 2.53 ± 0.13 R⊕; and TOI-561 e, with Pe = 77.2 d, Me = 16.0 ± 2.3 M⊕, Re = 2.67 ± 0.11 R⊕. Having a density of 3.0 ± 0.8 g cm−3, TOI-561 b is the lowest density USP planet known to date. Our N-body simulations confirm the stability of the system and predict a strong, anti-correlated, long-term transit time variation signal between planets d and e. The unusual density of the inner super-Earth and the dynamical interactions between the outer planets make TOI-561 an interesting follow-up target.

Flare Rates, Rotation Periods, and Spectroscopic Activity Indicators of a Volume-complete Sample of Mid- to Late-M Dwarfs within 15 pc

Abstract We present a study of flare rates, rotation periods, and spectroscopic activity indicators of 125 single stars within 15 parsecs and with masses between 0.1 and 0.3 M ⊙ observed during the first year of the TESS mission, with the goal of elucidating the relationship between these various magnetically connected phenomena. We gathered multiepoch high-resolution spectra of each target, and we measured equivalent widths of the activity indicators helium I D3, Hα, and the calcium infrared triplet line at 8542.09 Å. We present 18 new rotation periods from MEarth photometry and 19 new rotation periods from TESS photometry. We present a catalog of 1392 flares. After correcting for sensitivity, we find the slope of the flare frequency distribution for all stars to have a standard value of α = 1.98 ± 0.02. We determine R 31.5, the rate of flares per day with energies above E = 3.16 × 1031 ergs in the TESS bandpass. We find that below a critical value of Hα EW = −0.71 Å, log R 31.5 increases linearly with increasing Hα emission; above this value, log R 31.5 declines rapidly. The stars divide into two groups: 26% have Hα in emission, high flare rates with typical values of log R 31.5 = −1.30 ± 0.08, and have Rossby numbers <0.50. The remaining 74% show little to no Hα in emission and exhibit log R 31.5 < −3.86, with the majority of these stars not showing a single flare during the TESS observations.

The CARMENES search for exoplanets around M dwarfs

We report the discovery of a Neptune-like planet (LP 714-47 b, P = 4.05204 d, mb = 30.8 ± 1.5M⊕, Rb = 4.7 ± 0.3 R⊕) located in the “hot Neptune desert”. Confirmation of the TESS Object of Interest (TOI 442.01) was achieved with radial-velocity follow-up using CARMENES, ESPRESSO, HIRES, iSHELL, and PFS, as well as from photometric data using TESS, Spitzer, and ground-based photometry from MuSCAT2, TRAPPIST-South, MONET-South, the George Mason University telescope, the Las Cumbres Observatory Global Telescope network, the El Sauce telescope, the TÜBİTAK National Observatory, the University of Louisville Manner Telescope, and WASP-South. We also present high-spatial resolution adaptive optics imaging with the Gemini Near-Infrared Imager. The low uncertainties in the mass and radius determination place LP 714-47 b among physically well-characterised planets, allowing for a meaningful comparison with planet structure models. The host star LP 714-47 is a slowly rotating early M dwarf (Teff = 3950 ± 51 K) with a mass of 0.59 ± 0.02M⊙ and a radius of 0.58 ± 0.02R⊙. From long-term photometric monitoring and spectroscopic activity indicators, we determine a stellar rotation period of about 33 d. The stellar activity is also manifested as correlated noise in the radial-velocity data. In the power spectrum of the radial-velocity data, we detect a second signal with a period of 16 days in addition to the four-day signal of the planet. This could be shown to be a harmonic of the stellar rotation period or the signal of a second planet. It may be possible to tell the difference once more TESS data and radial-velocity data are obtained.

Disc light variability in the FUor star V646 Puppis as observed by TESS and from the ground

Context. We investigate small-scale light variations in V646 Pup occurring on timescales of days, weeks, and years. Aims. We aim to investigate whether this variability is similar to that observed in FU Ori. Methods. We observed V646 Pup on six occasions at the SAAO and CTIO between 2013 and 2018 with Johnson and Sloan filters, typically using a one-day cadence maintained for two to four weeks. We also utilised the public-domain 1512-day-long ASAS-SN light curve and TESS photometry obtained in 2019 over 24.1 days with a 30 min cadence. New SAAO low-resolution spectra assist in updating major disc parameters, while the archival high-resolution Keck spectra are used to search for temporal changes in the disc rotational profiles. Results. The ground-based observations confirm the constantly decreasing brightness of V646 Pup at the rate of 0.018 mag yr−1. Precise i-band sensitive TESS data show that the slight, 0.005−0.01 mag, light variations imposed on this general trend do consist of a few independent wave trains of an apparently time-coherent nature. Assuming that this is typical situation, based on an analysis of colour–magnitude diagrams obtained for earlier epochs, we were able to make a preliminarily inference that the bulk of the light changes observed could be due to the rotation of disc photosphere inhomogeneities, arising between 10–12 R⊙ from the star. We do not exclude the possibility that these inhomogeneities could also manifest themselves in the rotational profiles of the disc, as obtained from the high-resolution spectra. Assuming Keplerian rotation of these inhomogeneities, we give a preliminary determination of the stellar mass at 0.7–0.9 M⊙. Conclusions. Over certain weeks, at least, V646 Pup has shown time-coherent light variability pattern(s) that could be explained by the rotation of an inhomogeneous disc photosphere. These preliminary results are similar to those better established for FU Ori, which suggests a common driving mechanism(s).

Orbital and physical parameters of eclipsing binaries from the ASAS catalogue – XI. CHIRON investigation of long-period binaries

ABSTRACT We present the results of a spectroscopic campaign on eclipsing binaries with long orbital period (P = 20–75 d) carried out with the CHIRON spectrograph. Physical and orbital solutions for seven systems were derived from the V band, and I band ASAS, WASP, and TESS photometry, while radial velocities were calculated from high-quality optical spectra using a two-dimensional cross-correlation technique. The atmospheric parameters of the stars have been determined from the separated spectra. Most of our targets are composed of evolved stars (subgiants or red giants) but two systems show components in different phases of evolution and one possible merger. For four binaries, the masses and radii of the components were obtained with precision better than $3{{\ \rm per\ cent}}$. These objects provide very valuable information on stellar evolution.

TESS Photometry of the Precataclysmic Variable Wolf 1130AB

Abstract Wolf 1130 is a triple system containing an ultramassive white dwarf (Wolf 1130B), an M subdwarf (Wolf 1130A) and a T8 subdwarf (Wolf 1130C). We set out to determine a precise mass for Wolf 1130B by phase-folding TESS photometry to the previously reported orbital period. Each orbit was fit for ellipsoidal, Doppler beaming, and thermal photometric variability. We found that the measured beaming amplitude of Wolf 1130AB is nearly triple the theoretical expectation, which we assign to the short-wavelength filter cutoff of TESS and features in the M subdwarf spectrum. The photometric amplitudes suggest inflation of Wolf 1130A by as much as 20%, possibly due to its rapid rotation under tidal locking. TESS photometry can be used to obtain masses for short-period binary systems, but photometric precision limits the utility in the case of Wolf 1130AB.

Photometry of 10 Million Stars from the First Two Years of TESS Full Frame Images: Part II

Abstract We present light curves from a magnitude limited set of stars and other stationary luminous objects from the TESS Full Frame Images, as reduced by the MIT Quick Look Pipeline (QLP). Our light curves cover the full two-year TESS Primary Mission and include ∼14,770,000 and ∼9,600,000 individual light curve segments in the Southern and Northern ecliptic hemispheres, respectively. We describe the detrending techniques we used to create the light curves, and compare the noise properties with theoretical expectations. All of the QLP light curves are available at MAST as a High Level Science Product (HLSP) via doi:10.17909/t9-r086-e880 (https://archive.stsci.edu/hlsp/qlp). This is the largest collection of TESS photometry available to the public to date.

Planetary system LHS 1140 revisited with ESPRESSO and TESS

Context. LHS 1140 is an M dwarf known to host two transiting planets at orbital periods of 3.77 and 24.7 days. They were detected with HARPS and Spitzer. The external planet (LHS 1140 b) is a rocky super-Earth that is located in the middle of the habitable zone of this low-mass star. All these properties place this system at the forefront of the habitable exoplanet exploration, and it therefore constitutes a relevant case for further astrobiological studies, including atmospheric observations. Aims. We further characterize this system by improving the physical and orbital properties of the known planets, search for additional planetary-mass components in the system, and explore the possibility of co-orbitals. Methods. We collected 113 new high-precision radial velocity observations with ESPRESSO over a 1.5-yr time span with an average photon-noise precision of 1.07 m s−1. We performed an extensive analysis of the HARPS and ESPRESSO datasets and also analyzed them together with the new TESS photometry. We analyzed the Bayesian evidence of several models with different numbers of planets and orbital configurations. Results. We significantly improve our knowledge of the properties of the known planets LHS 1140 b (Pb ~ 24.7 days) and LHS 1140 c (Pc ~ 3.77 days). We determine new masses with a precision of 6% for LHS 1140 b (6.48 ± 0.46 M⊕) and 9% for LHS 1140 c (mc = 1.78 ± 0.17 M⊕). This reduces the uncertainties relative to previously published values by half. Although both planets have Earth-like bulk compositions, the internal structure analysis suggests that LHS 1140 b might be iron-enriched and LHS 1140 c might be a true Earth twin. In both cases, the water content is compatible to a maximum fraction of 10–12% in mass, which is equivalent to a deep ocean layer of 779 ± 650 km for the habitable-zone planet LHS 1140 b. Our results also provide evidence for a new planet candidate in the system (md = 4.8 ± 1.1M⊕) on a 78.9-day orbital period, which is detected through three independent methods. The analysis also allows us to discard other planets above 0.5 M⊕ for periods shorter than 10 days and above 2 M⊕ for periods up to one year. Finally, our co-orbital analysis discards co-orbital planets in the tadpole and horseshoe configurations of LHS 1140 b down to 1 M⊕ with a 95% confidence level (twice better than with the previous HARPS dataset). Indications for a possible co-orbital signal in LHS 1140 c are detected in both radial velocity (alternatively explained by a high eccentricity) and photometric data (alternatively explained by systematics), however. Conclusions. The new precise measurements of the planet properties of the two transiting planets in LHS 1140 as well as the detection of the planet candidate LHS 1140 d make this system a key target for atmospheric studies of rocky worlds at different stellar irradiations.

Doppler Beaming of M Dwarfs in TESS, Kepler/K2, and Gaia Photometry

Abstract The Doppler beaming amplitude of a M dwarf is amplified relative to a blackbody of the same temperature because of deep TiO absorption features in M dwarf spectra. A strong Na feature at 5890 Å coincides with the short wavelength cutoff of the Transiting Exoplanet Survey Satellite response function, which also increases the beaming amplitude. As a result, the Doppler beaming effect for a 3000 K object is a factor of 1.4–2.0 times greater than predicted for a blackbody. Underestimating the Doppler beaming coefficient could result in mass overestimates when using the photometric beaming amplitude to determine stellar properties. This is especially important for M dwarfs in short period binary systems with massive white dwarf, neutron star or black hole companions.

A super-Earth and a sub-Neptune orbiting the bright, quiet M3 dwarf TOI-1266

We report the discovery and characterisation of a super-Earth and a sub-Neptune transiting the bright (K = 8.8), quiet, and nearby (37 pc) M3V dwarf TOI-1266. We validate the planetary nature of TOI-1266 b and c using four sectors of TESS photometry and data from the newly-commissioned 1-m SAINT-EX telescope located in San Pedro Mártir (México). We also include additional ground-based follow-up photometry as well as high-resolution spectroscopy and high-angular imaging observations. The inner, larger planet has a radius of R = 2.37−0.12+0.16 R⊕ and an orbital period of 10.9 days. The outer, smaller planet has a radius of R = 1.56−0.13+0.15 R⊕ on an 18.8-day orbit. The data are found to be consistent with circular, co-planar and stable orbits that are weakly influenced by the 2:1 mean motion resonance. Our TTV analysis of the combined dataset enables model-independent constraints on the masses and eccentricities of the planets. We find planetary masses of Mp = 13.5−9.0+11.0 M⊕ (<36.8 M⊕ at 2-σ) for TOI-1266 b and 2.2−1.5+2.0 M⊕ (<5.7 M⊕ at 2-σ) for TOI-1266 c. We find small but non-zero orbital eccentricities of 0.09−0.05+0.06 (<0.21 at 2-σ) for TOI-1266 b and 0.04 ± 0.03 (< 0.10 at 2-σ) for TOI-1266 c. The equilibrium temperatures of both planets are of 413 ± 20 and 344 ± 16 K, respectively, assuming a null Bond albedo and uniform heat redistribution from the day-side to the night-side hemisphere. The host brightness and negligible activity combined with the planetary system architecture and favourable planet-to-star radii ratios makes TOI-1266 an exquisite system for a detailed characterisation.