arXiv subjects

H. J. Deeg

Publications and source records attributed to H. J. Deeg.

At least 37 records · Page 2Linked to original sources

arXiv2020

A planetary system with two transiting mini-Neptunes near the radius valley transition around the bright M dwarf TOI-776

We report the discovery and characterization of two transiting planets around the bright M1 V star LP 961-53 (TOI-776, J = 8.5 mag, M = 0.54+-0.03 Msun) detected during Sector 10 observations of the Transiting Exoplanet Survey Satellite (TESS). Combining the TESS photometry with HARPS radial velocities, as well as ground-based follow-up transit observations from MEarth and LCOGT telescopes, we measured for the inner planet, TOI-776 b, a period of 8.25 d, a radius of 1.85+-0.13 Re, and a mass of 4.0+-0.9 Me; and for the outer planet, TOI-776 c, a period of 15.66 d, a radius of 2.02+-0.14 Re, and a mass of 5.3+-1.8 Me. The Doppler data shows one additional signal, with a period of 34 d, associated with the rotational period of the star. The analysis of fifteen years of ground-based photometric monitoring data and the inspection of different spectral line indicators confirm this assumption. The bulk densities of TOI-776 b and c allow for a wide range of possible interior and atmospheric compositions. However, both planets have retained a significant atmosphere, with slightly different envelope mass fractions. Thanks to their location near the radius gap for M dwarfs, we can start to explore the mechanism(s) responsible for the radius valley emergence around low-mass stars as compared to solar-like stars. While a larger sample of well-characterized planets in this parameter space is still needed to draw firm conclusions, we tentatively estimate that the stellar mass below which thermally-driven mass loss is no longer the main formation pathway for sculpting the radius valley is between 0.63 and 0.54 Msun. Due to the brightness of the star, the TOI-776 system is also an excellent target for the James Webb Space Telescope, providing a remarkable laboratory to break the degeneracy in planetary interior models and to test formation and evolution theories of small planets around low-mass stars.

astro-ph.EP↗

arXiv2020

The TOI-763 system: sub-Neptunes orbiting a Sun-like star

We report the discovery of a planetary system orbiting TOI-763 (aka CD-39 7945), a $V=10.2$, high proper motion G-type dwarf star that was photometrically monitored by the TESS space mission in Sector 10. We obtain and model the stellar spectrum and find an object slightly smaller than the Sun, and somewhat older, but with a similar metallicity. Two planet candidates were found in the light curve to be transiting the star. Combining TESS transit photometry with HARPS high-precision radial velocity follow-up measurements confirm the planetary nature of these transit signals. We determine masses, radii, and bulk densities of these two planets. A third planet candidate was discovered serendipitously in the radial velocity data. The inner transiting planet,TOI-763 b, has an orbital period of $P_\mathrm{b}$ = 5.6~days, a mass of $M_\mathrm{b}$ = $9.8\pm0.8$ $M_\oplus$, and a radius of $R_\mathrm{b}$ = $2.37\pm0.10$ $R_\oplus$. The second transiting planet,TOI-763 c, has an orbital period of $P_\mathrm{c}$ = 12.3~days, a mass of $M_\mathrm{c}$ = $9.3\pm1.0$ $M_\oplus$, and a radius of $R_\mathrm{c}$ = $2.87\pm0.11$ $R_\oplus$. We find the outermost planet candidate to orbit the star with a period of $\sim$48~days. If confirmed as a planet it would have a minimum mass of $M_\mathrm{d}$ = $9.5\pm1.6$ $M_\oplus$. We investigated the TESS light curve in order to search for a mono transit by planet~d without success. We discuss the importance and implications of this planetary system in terms of the geometrical arrangements of planets orbiting G-type stars.

astro-ph.EP↗

arXiv2020

Three planets transiting the evolved star EPIC 249893012: a hot 8.8-M$_\oplus$ super-Earth and two warm 14.7 and 10.2-M$_\oplus$ sub-Neptunes

We report the discovery of a new planetary system with three transiting planets, one super-Earth and two sub-Neptunes, that orbit EPIC\,249893012, a G8\,IV-V evolved star ($M_\star$\,=\,1.05\,$\pm$\,0.05\,$M_\odot$, $R_\star$\,=\,1.71\,$\pm$\,0.04\,$R_\odot$, $T_\mathrm{eff}$\,=5430\,$\pm$\,85\,K). The star is just leaving the main sequence. We combined \ktwo \ photometry with IRCS adaptive-optics imaging and HARPS, HARPS-N, and CARMENES high-precision radial velocity measurements to confirm the planetary system, determine the stellar parameters, and measure radii, masses, and densities of the three planets. With an orbital period of $3.5949^{+0.0007}_{-0.0007}$ days, a mass of $8.75^{+1.09}_{-1.08}\ M_{\oplus}$ , and a radius of $1.95^{+0.09}_{-0.08}\ R_{\oplus}$, the inner planet b is compatible with nickel-iron core and a silicate mantle ($ρ_b= 6.39^{+1.19}_{-1.04}$ g cm$^{-3}$). Planets c and d with orbital periods of $15.624^{+0.001}_{-0.001}$ and $35.747^{+0.005}_{-0.005}$ days, respectively, have masses and radii of $14.67^{+1,84}_{-1.89}\ M_{\oplus}$ and $3.67^{+0.17}_{-0.14}\ R_{\oplus}$ and $10.18^{+2.46}_{-2.42}\ M_{\oplus}$ and $3.94^{+0.13}_{-0.12}\ R_{\oplus}$, respectively, yielding a mean density of $1.62^{+0.30}_{-0.29}$ and $0.91^{+0.25}_{-0.23}$ g cm$^{-3}$, respectively. The radius of planet b lies in the transition region between rocky and gaseous planets, but its density is consistent with a rocky composition. Its semimajor axis and the corresponding photoevaporation levels to which the planet has been exposed might explain its measured density today. In contrast, the densities and semimajor axes of planets c and d suggest a very thick atmosphere. The singularity of this system, which orbits a slightly evolved star that is just leaving the main sequence, makes it a good candidate for a deeper study from a dynamical point of view.

astro-ph.EP↗

arXiv2020

The BRITE-SONG of Aldebaran -- Stellar Music in three voices

Solar-like oscillations in red-giant stars are now commonly detected in thousands of stars with space telescopes such as the NASA Kepler mission. Parallel radial velocity and photometric measurements would help to better understand the physics governing the amplitudes of solar-like oscillators. Yet, most target stars for space photometry are too faint for light-demanding ground-based spectroscopy. The BRITE Constellation satellites provide a unique opportunity of two-color monitoring of the flux variations of bright luminous red giants. Those targets are also bright enough to be monitored with high-resolution spectrographs on small telescopes, such as the SONG Network. In these proceedings, we provide a first overview of our comprehensive, multi-year campaign utilizing both BRITE and SONG to seismically characterize Aldebaran, one of the brightest red giants in the sky. Because luminous red giants can be seen at large distances, such well-characterized objects will serve as benchmark stars for galactic archeology.

astro-ph.SR↗

arXiv2019

Radial velocity confirmation of K2-100b: a young, highly irradiated, and low density transiting hot Neptune

We present a detailed analysis of HARPS-N radial velocity observations of K2-100, a young and active star in the Praesepe cluster, which hosts a transiting planet with a period of 1.7 days. We model the activity-induced radial velocity variations of the host star with a multi-dimensional Gaussian Process framework and detect a planetary signal of $10.6 \pm 3.0 {\rm m\,s^{-1}}$, which matches the transit ephemeris, and translates to a planet mass of $21.8 \pm 6.2 M_\oplus$. We perform a suite of validation tests to confirm that our detected signal is genuine. This is the first mass measurement for a transiting planet in a young open cluster. The relatively low density of the planet, $2.04^{+0.66}_{-0.61} {\rm g\,cm^{-3}}$, implies that K2-100b retains a significant volatile envelope. We estimate that the planet is losing its atmosphere at a rate of $10^{11}-10^{12}\,{\rm g\,s^{-1}}$ due to the high level of radiation it receives from its host star.

astro-ph.EP↗

arXiv2019

Kepler Object of Interest Network III. Kepler-82f: A new non-transiting $21 M_\bigoplus$ planet from photodynamical modelling

Context. The Kepler Object of Interest Network (KOINet) is a multi-site network of telescopes around the globe organised for follow-up observations of transiting planet candidate Kepler objects of interest (KOIs) with large transit timing variations (TTVs). The main goal of KOINet is the completion of their TTV curves as the Kepler telescope stopped observing the original Kepler field in 2013. Aims. We ensure a comprehensive characterisation of the investigated systems by analysing Kepler data combined with new ground-based transit data using a photodynamical model. This method is applied to the Kepler-82 system leading to its first dynamic analysis. Methods. In order to provide a coherent description of all observations simultaneously, we combine the numerical integration of the gravitational dynamics of a system over the time span of observations with a transit light curve model. To explore the model parameter space, this photodynamical model is coupled with a Markov chain Monte Carlo algorithm. Results. The Kepler-82b/c system shows sinusoidal TTVs due to their near 2:1 resonance dynamical interaction. An additional chopping effect in the TTVs of Kepler-82c hints to a further planet near the 3:2 or 3:1 resonance. We photodynamically analysed Kepler long- and short-cadence data and three new transit observations obtained by KOINet between 2014 and 2018. Our result reveals a non-transiting outer planet with a mass of $m_f=20.9\pm1.0\;M_\bigoplus$ near the 3:2 resonance to the outermost known planet, Kepler-82c. Furthermore, we determined the densities of planets b and c to the significantly more precise values $ρ_b=0.98_{-0.14}^{+0.10}\;\text{g cm}^{-3}$ and $ρ_c=0.494_{-0.077}^{+0.066}\;\text{g cm}^{-3}$.

astro-ph.EP↗

arXiv2018

K2-140b and K2-180b - Characterization of a hot Jupiter and a mini-Neptune from the K2 mission

We report the independent discovery and characterization of two K2 planets: K2-180b, a mini-Neptune-size planet in an 8.9-day orbit transiting a V = 12.6 mag, metal-poor ([Fe/H] =$-0.65\pm0.10$) K2V star in K2 campaign 5; K2-140b, a transiting hot Jupiter in a 6.6-day orbit around a V = 12.6 mag G6V ([Fe/H] = $+0.10\pm0.10$) star in K2 campaign 10. Our results are based on K2 time-series photometry combined with high-spatial resolution imaging and high-precision radial velocity measurements. We present the first mass measurement of K2-180b. K2-180b has a mass of $M_\mathrm{p}=11.3\pm1.9$ ${M_{\oplus}}$ and a radius of $R_\mathrm{p}=2.2\pm0.1$ ${R_{\oplus}}$ , yielding a mean density of $ρ_\mathrm{p}=5.6\pm1.9\,g\,cm^{-3}$, suggesting a rock composition. Given its radius, K2-180b is above the region of the so-called `planetary radius gap'. K2-180b is in addition not only one of the densest mini-Neptune-size planets, but also one of the few mini-Neptune-size planets known to transit a metal-poor star. We also constrain the planetary and orbital parameters of K2-140b and show that, given the currently available Doppler measurements, the eccentricity is consistent with zero, contrary to the results of a previous study.

astro-ph.EP↗

arXiv2018

Super-Earth of 8 Mearth in a 2.2-day orbit around the K5V star K2-216

The KESPRINT consortium identified K2-216 as a planetary candidate host star in the K2 space mission Campaign 8 field with a transiting super-Earth. The planet has recently been validated as well. Our aim was to confirm the detection and derive the main physical characteristics of K2-216b, including the mass. We performed a series of follow-up observations: high resolution imaging with the FastCam camera at the TCS, the Infrared Camera and Spectrograph at Subaru, and high resolution spectroscopy with HARPS (ESO, La Silla), HARPS-N (TNG), and FIES (NOT). The stellar spectra were analyzed with the SpecMatch-Emp and SME codes to derive the stellar fundamental properties. We analyzed the K2 light curve with the Pyaneti software. The radial-velocity measurements were modelled with both a Gaussian process (GP) regression and the floating chunk offset (FCO) technique to simultaneously model the planetary signal and correlated noise associated with stellar activity. Imaging confirms that K2-216 is a single star. Our analysis discloses that the star is a moderately active K5V star of mass 0.70+/-0.03 Msun and radius 0.72+/-0.03 Rsun. Planet b is found to have a radius of 1.75+0.17-0.10 Rearth and a 2.17-day orbit in agreement with previous results. We find consistent results for the planet mass from both models: 7.4+/-2.2 Mearth from the GP regression, and 8.0+/-1.6 Mearth from the FCO technique, which implies that this planet is a super-Earth. The planet parameters put planet b in the middle of, or just below, the gap of the radius distribution of small planets. The density is consistent with a rocky composition of primarily iron and magnesium silicate. In agreement with theoretical predictions, we find that the planet is a remnant core, stripped of its atmosphere, and is one of the largest planets found that has lost its atmosphere.

astro-ph.EP↗

arXiv2018

Kepler Object of Interest Network II. Photodynamical modelling of Kepler-9 over 8 years of transit observations

The Kepler Object of Interest Network (KOINet) is a multi-site network of telescopes around the globe organised to follow up transiting planet candidate KOIs with large transit timing variations (TTVs). Its main goal is to complete their TTV curves, as the Kepler telescope no longer observes the original Kepler field. Combining Kepler and new ground-based transit data we improve the modelling of these systems. To this end, we have developed a photodynamical model, and we demonstrate its performance using the Kepler-9 system as an example. Our comprehensive analysis combines the numerical integration of the system's dynamics over the time span of the observations along with the transit light curve model. This model is coupled with a Markov chain Monte Carlo algorithm, allowing the exploration of the model parameter space. Applied to the Kepler-9 long cadence data, short cadence data and 13 new transit observations collected by KOINet between the years 2014 to 2017, our modelling provides well constrained predictions for the next transits and the system's parameters. We have determined the densities of the planets Kepler-9b and 9c to the very precise values of rho_b = 0.439 +/-0.023 g/cm3 and rho_c = 0.322 +/- 0.017 g/cm3. Our analysis reveals that Kepler-9c will stop transiting in about 30 years. This results from strong dynamical interactions between Kepler-9b and 9c, near 2:1 resonance, that leads to a periodic change in inclination. Over the next 30 years the inclination of Kepler-9c (-9b) will decrease (increase) slowly. This should be measurable by a substantial decrease (increase) in the transit duration, in as soon as a few years' time. Observations that contradict this prediction might indicate the presence of additional objects. If this prediction proves true, this behaviour opens up a unique chance to scan the different latitudes of a star.

astro-ph.EP↗

arXiv2018

Planets, candidates, and binaries from the CoRoT/Exoplanet programme: the CoRoT transit catalogue

We provide the catalogue of all transit-like features, including false alarms, detected by the CoRoT exoplanet teams in the 177 454 light curves of the mission. All these detections have been re-analysed with the same softwares so that to ensure their homogeneous analysis. Although the vetting process involves some human evaluation, it also involves a simple binary flag system over basic tests: detection significance, presence of a secondary, difference between odd and even depths, colour dependence, V-shape transit, and duration of the transit. We also gathered the information from the large accompanying ground-based programme carried out on the planet candidates and checked how useful the flag system could have been at the vetting stage of the candidates. In total, we identified and separated 824 false alarms of various kind, 2269 eclipsing binaries among which 616 are contact binaries and 1653 are detached ones, 37 planets and brown dwarfs, and 557 planet candidates. For the planet candidates, the catalogue gives not only their transit parameters but also the products of their light curve modelling, together with a summary of the outcome of follow-up observations when carried out and their current status. Among the planet candidates whose nature remains unresolved, we estimate that 8 +/- 3 planets are still to be identified. We derived planet and brown dwarf occurrences and confirm disagreements with Kepler estimates: small-size planets with orbital period less than ten days are underabundant by a factor of three in the CoRoT fields whereas giant planets are overabundant by a factor of two. These preliminary results would however deserve further investigations using the recently released CoRoT light curves that are corrected of the various instrumental effects and a homogeneous analysis of the stellar populations observed by the two missions.

astro-ph.EP↗

arXiv2018

Kepler Object of Interest Network I. First results combining ground and space-based observations of Kepler systems with transit timing variations

During its four years of photometric observations, the Kepler space telescope detected thousands of exoplanets and exoplanet candidates. One of Kepler's greatest heritages has been the confirmation and characterization of hundreds of multi-planet systems via Transit Timing Variations (TTVs). However, there are many interesting candidate systems displaying TTVs on such long time scales that the existing Kepler observations are of insufficient length to confirm and characterize them by means of this technique. To continue with Kepler's unique work we have organized the "Kepler Object of Interest Network" (KOINet). The goals of KOINet are, among others, to complete the TTV curves of systems where Kepler did not cover the interaction timescales well. KOINet has been operational since March, 2014. Here we show some promising first results obtained from analyzing seven primary transits of KOI-0410.01, KOI-0525.01, KOI-0760.01, and KOI-0902.01 in addition to Kepler data, acquired during the first and second observing seasons of KOINet. While carefully choosing the targets we set demanding constraints about timing precision (at least 1 minute) and photometric precision (as good as 1 part per thousand) that were achieved by means of our observing strategies and data analysis techniques. For KOI-0410.01, new transit data revealed a turn-over of its TTVs. We carried out an in-depth study of the system, that is identified in the NASA's Data Validation Report as false positive. Among others, we investigated a gravitationally-bound hierarchical triple star system, and a planet-star system. While the simultaneous transit fitting of ground and space-based data allowed for a planet solution, we could not fully reject the three-star scenario. New data, already scheduled in the upcoming 2018 observing season, will set tighter constraints on the nature of the system.

astro-ph.EP↗

arXiv2018

Non-grey dimming events of KIC 8462852 from GTC spectrophotometry

We report ground-based spectrophotometry of KIC 8462852, during its first dimming events since the end of the Kepler mission. The dimmings show a clear colour-signature, and are deeper in visual blue wavelengths than in red ones. The flux loss' wavelength dependency can be described with an Ångström absorption coefficient of $2.19\pm0.45$, which is compatible with absorption by optically thin dust with particle sizes on the order of 0.0015 to 0.15 $μ$m. These particles would be smaller than is required to be resistant against blow-out by radiation pressure when close to the star. During occultation events, these particles must be replenished on time-scales of days. If dust is indeed the source of KIC 8462852's dimming events, deeper dimming events should show more neutral colours, as is expected from optically thick absorbers.

astro-ph.SR↗

arXiv2017

K2-139 b: a low-mass warm Jupiter on a 29-day orbit transiting an active K0 V star

We announce the discovery of K2-139 b (EPIC 218916923 b), a transiting warm-Jupiter ($T_\mathrm{eq}$=547$\pm$25 K) on a 29-day orbit around an active (log $R^\prime_\mathrm{HK}$ = $-$4.46 $\pm$ 0.06) K0 V star in K2 Campaign 7. We derive the system's parameters by combining the K2 photometry with ground-based follow-up observations. With a mass of~$0.387 _{ - 0.075 } ^ {+ 0.083 } M_{\rm J}$ and radius of $0.808 _{ - 0.033 } ^ {+ 0.034 } R_{\rm J}$, K2-139 b is one of the transiting warm Jupiters with the lowest mass known to date. The planetary mean density of $0.91 _{ - 0.20} ^ { + 0.24 }$ $\mathrm{g cm^{-3}}$ can be explained with a core of $\sim$50 $M_\oplus$. Given the brightness of the host star ($V$ = 11.653 mag), the relatively short transit duration ($\sim$5 hours), and the expected amplitude of the Rossiter-McLaughlin effect ($\sim25 {\rm m s^{-1}}$ ), K2-139 is an ideal target to measure the spin-orbit angle of a planetary system hosting a warm Jupiter.

astro-ph.EP↗

arXiv2017

Search for rings and satellites around the exoplanet CoRoT-9b using Spitzer photometry

Using Spitzer photometry at 4.5 microns, we search for rings and satellites around the long period transiting planet CoRoT-9b. We observed two transits in 2010 and 2011. From their non-detection, we derive upper limits on the plausible physical characteristics of these objects in the planet environment. We show that a satellite larger than about 2.5 Earth radii is excluded at 3-$σ$ for a wide range of elongations at the two epochs of observations. Combining the two observations, we conclude that rings are excluded for a wide variety of sizes and inclination. We find that for a ring extending up to the Roche limit, its inclination angle from the edge-on configuration as seen from the Earth must be lower than 13° in the case of silicate composition and lower than 3° in the case of material with water ice density.

astro-ph.EP↗

arXiv2017

A deeper view of the CoRoT-9 planetary system. A small non-zero eccentricity for CoRoT-9b likely generated by planet-planet scattering

CoRoT-9b is one of the rare long-period (P=95.3 days) transiting giant planets with a measured mass known to date. We present a new analysis of the CoRoT-9 system based on five years of radial-velocity (RV) monitoring with HARPS and three new space-based transits observed with CoRoT and Spitzer. Combining our new data with already published measurements we redetermine the CoRoT-9 system parameters and find good agreement with the published values. We uncover a higher significance for the small but non-zero eccentricity of CoRoT-9b ($e=0.133^{+0.042}_{-0.037}$) and find no evidence for additional planets in the system. We use simulations of planet-planet scattering to show that the eccentricity of CoRoT-9b may have been generated by an instability in which a $\sim 50~M_\oplus$ planet was ejected from the system. This scattering would not have produced a spin-orbit misalignment, so we predict that CoRoT-9b orbit should lie within a few degrees of the initial plane of the protoplanetary disk. As a consequence, any significant stellar obliquity would indicate that the disk was primordially tilted.

astro-ph.EP↗

arXiv2017

Mass determination of K2-19b and K2-19c from radial velocities and transit timing variations

We present FIES@NOT, HARPS-N@TNG, and HARPS@ESO-3.6m radial velocity follow-up observations of K2-19, a compact planetary system hosting three planets, of which the two larger ones, namely K2-19b and K2-19c, are close to the 3:2 mean motion resonance. An analysis considering only the radial velocity measurements detects K2-19b, the largest and most massive planet in the system, with a mass of $54.8\pm7.5$~M${_\oplus}$ and provides a marginal detection of K2-19c, with a mass of M$_\mathrm{c}$=$5.9^{+7.6}_{-4.3}$ M$_\oplus$. We also used the TRADES code to simultaneously model both our RV measurements and the existing transit-timing measurements. We derived a mass of $54.4\pm8.9$~M${_\oplus}$ for K2-19b and of $7.5^{+3.0}_{-1.4}$~M${_\oplus}$ for K2-19c. A prior K2-19b mass estimated by Barros et al. 2015, based principally on a photodynamical analysis of K2-19's light-curve, is consistent with both analysis, our combined TTV and RV analysis, and with our analysis based purely on RV measurements. Differences remain mainly in the errors of the more lightweight planet, driven likely by the limited precision of the RV measurements and possibly some yet unrecognized systematics.

astro-ph.EP↗

arXiv2016

Limits to the presence of transiting circumbinary planets in CoRoT data

The CoRoT mission during its flight-phase 2007-2012 delivered the light-curves for over 2000 eclipsing binaries. Data from the Kepler mission have proven the existence of several transiting circumbinary planets. Albeit light-curves from CoRoT have typically lower precision and shorter coverage, CoRoT's number of targets is similar to Kepler, and some of the known circumbinary planets could potentially be detected in CoRoT data as well. The aim of this work has been a revision of the entire CoRoT data-set for the presence of circumbinary planets, and the derivation of limits to the abundances of such planets. We developed a code which removes the light curve of the eclipsing binaries and searches for quasi-periodic transit-like features in a light curve after removal of binary eclipses and instrumental features. The code needs little information on the sample systems and can be used for other space missions as well, like Kepler, K2, TESS and PLATO. The code is broad in the requirements leading to detections, but was tuned to deliver an amount of detections that is manageable in a subsequent, mainly visual, revision about their nature. In the CoRoT sample we identified three planet candidates whose transits would have arisen from a single pass across the central binary. No candidates remained however with transit events from multiple planetary orbits. We calculated the upper limits for the number of Jupiter, Saturn and Neptune sized planets in co-planar orbits for different orbital period ranges. We found that there are much less giant planets in short-periodic orbits around close binary systems than around single stars.

astro-ph.EP↗

arXiv2016

K2-99: a subgiant hosting a transiting warm Jupiter in an eccentric orbit and a long-period companion

We report the discovery from K2 of a transiting planet in an 18.25-d, eccentric (0.19$\pm$ 0.04) orbit around K2-99, an 11th magnitude subgiant in Virgo. We confirm the planetary nature of the companion with radial velocities, and determine that the star is a metal-rich ([Fe/H] = 0.20$\pm$0.05) subgiant, with mass $1.60^{+0.14}_{-0.10}~M_\odot$ and radius $3.1\pm 0.1~R_\odot$. The planet has a mass of $0.97\pm0.09~M_{\rm Jup}$ and a radius $1.29\pm0.05~R_{\rm Jup}$. A measured systemic radial acceleration of $-2.12\pm0.04~{\rm m s^{-1} d^{-1}}$ offers compelling evidence for the existence of a third body in the system, perhaps a brown dwarf orbiting with a period of several hundred days.

astro-ph.EP↗