- ID:
- ivo://CDS.VizieR/J/A+A/618/A41
- Title:
- Photometry of Kepler-9b and c transits
- Short Name:
- J/A+A/618/A41
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The Kepler-9b/c system is a prime example of anti-correlated transit timing variations (TTVs). These TTVs results from the dynamical interaction amplified by the near 2:1 period resonance of the planets. The dynamical cycle was only almost finished when the Kepler telescope stopped the observations on that field. To complement the dynamical cycle of this and other Kepler Objects of Interest (KOIs) showing TTVs, the KOINet was build to organize follow-up observations with ground-based telescopes. These follow-up observations of Kepler-9b/c transits were used in a detailed photodynamical modelling of the system and increased the accuracy of the derivable system parameters.
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- ID:
- ivo://CDS.VizieR/J/AJ/162/203
- Title:
- Photometry of OGLE-2019-BLG-0304 with OGLE & KMTNet
- Short Name:
- J/AJ/162/203
- Date:
- 01 Feb 2022 07:08:03
- Publisher:
- CDS
- Description:
- We analyze the microlensing event OGLE-2019-BLG-0304, whose light curve exhibits two distinctive features: a deviation in the peak region and a second bump appearing ~61days after the main peak. Although a binary-lens model can explain the overall features, it leaves subtle but noticeable residuals in the peak region. We find that the residuals can be explained by the presence of either a planetary companion located close to the primary of the binary lens (3L1S model) or an additional close companion to the source (2L2S model). Although the 3L1S model is favored over the 2L2S model, with {Delta}{chi}2~8, securely resolving the degeneracy between the two models is difficult with the currently available photometric data. According to the 3L1S interpretation, the lens is a planetary system, in which a planet with a mass 0.51_-0.23_^+0.51^M_J_ is in an S-type orbit around a binary composed of stars with masses 0.27_-0.12_^+0.27^M{odot} and 0.10_-0.04_^+0.10^M{odot}. According to the 2L2S interpretation, however, the source is composed of G- and K-type giant stars and the lens is composed of a low-mass M dwarf and a brown dwarf with masses 0.12_-0.05_^+0.12^M{odot} and 0.045_-.019_^+0.045^M{odot}, respectively. The event illustrates the need for thorough model testing in the interpretation of lensing events with complex features in light curves.
- ID:
- ivo://CDS.VizieR/J/AJ/155/12
- Title:
- Photometry of Proxima Centauri observed by BSST
- Short Name:
- J/AJ/155/12
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Proxima Centauri is known as the closest star to the Sun. Recently, radial velocity (RV) observations revealed the existence of an Earth-mass planet around it. With an orbital period of ~11 days, Proxima Centauri b is probably in the habitable zone of its host star. We undertook a photometric monitoring campaign to search for its transit, using the Bright Star Survey Telescope at the Zhongshan Station in Antarctica. A transit-like signal appearing on 2016 September 8 has been tentatively identified. Its midtime, T_C_=2457640.1990+/-0.0017 HJD, is consistent with the predicted ephemeris based on the RV orbit in a 1{sigma} confidence interval. Time-correlated noise is pronounced in the light curve of Proxima Centauri, affecting the detection of transits. We develop a technique, in a Gaussian process framework, to gauge the statistical significance of a potential transit detection. The tentative transit signal reported here has a confidence level of 2.5{sigma}. Further detection of its periodic signals is necessary to confirm the planetary transit of Proxima Centauri b. We plan to monitor Proxima Centauri in the next polar night at Dome A in Antarctica, taking advantage of continuous darkness. Kipping et al. (2017, J/AJ/153/93) reported two tentative transit-like signals of Proxima Centauri b observed by the Microvariability and Oscillation of Stars space telescope in 2014 and 2015. The midtransit time of our detection is 138 minutes later than that predicted by their transit ephemeris. If all of the signals are real transits, the misalignment of the epochs plausibly suggests transit timing variations of Proxima Centauri b induced by an outer planet in this system.
- ID:
- ivo://CDS.VizieR/J/AJ/155/257
- Title:
- Photometry & RV follow-up observations of K2-18
- Short Name:
- J/AJ/155/257
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- K2-18 is a nearby M2.5 dwarf, located at 34 pc and hosting a transiting planet that was first discovered by the K2 mission and later confirmed with Spitzer Space Telescope observations. With a radius of ~2 R_{Earth}_ and an orbital period of ~33 days, the planet lies in the temperate zone of its host star and receives stellar irradiation similar to that of Earth. Here we perform radial velocity follow-up observations with the visual channel of CARMENES with the goal of determining the mass and density of the planet. We measure a planetary semi-amplitude of K_b_~3.5 m/s and a mass of M_b_~9 M_{Earth}_, yielding a bulk density around {rho}_b_~4 g/cm^3^. This indicates a low-mass planet with a composition consistent with a solid core and a volatile-rich envelope. A signal at 9 days was recently reported using radial velocity measurements taken with the HARPS spectrograph. This was interpreted as being due to a second planet. We see a weaker, time- and wavelength-dependent signal in the CARMENES data set and thus favor stellar activity for its origin. K2-18 b joins the growing group of low-mass planets detected in the temperate zone of M dwarfs. The brightness of the host star in the near-infrared makes the system a good target for detailed atmospheric studies with the James Webb Space Telescope.
- ID:
- ivo://CDS.VizieR/J/AJ/159/173
- Title:
- Photometry & RVs of 4 dwarfs hosting giant planets
- Short Name:
- J/AJ/159/173
- Date:
- 09 Dec 2021
- Publisher:
- CDS
- Description:
- We report the discovery of four transiting giant planets around K-dwarfs. The planets HATS-47b, HATS-48Ab, HATS-49b, and HATS-72b have masses of 0.369_-0.021_^+0.031^M_J_, 0.243_-0.030_^+0.022^M_J_, 0.353_-0.027_^+0.038^M_J_, and 0.1254{+/-}0.0039M_J_, respectively, and radii of 1.117{+/-}0.014R_J_, 0.800{+/-}0.015R_J_, 0.765{+/-}0.013R_J_, and 0.7224{+/-}0.0032R_J_, respectively. The planets orbit close to their host stars with orbital periods of 3.9228days, 3.1317days, 4.1480days, and 7.3279days, respectively. The hosts are main-sequence K-dwarfs with masses of 0.674_-0.012_^+0.016^M_{odot}_, 0.7279{+/-}0.0066M_{odot}_, 0.7133{+/-}0.0075M_{odot}_, and 0.7311{+/-}0.0028, and with V-band magnitudes of V=14.829{+/-}0.010, 14.35{+/-}0.11, 14.998{+/-}0.040 and 12.469{+/-}0.010. The super-Neptune HATS-72b (a.k.a. WASP-191b and TOI294.01) was independently identified as a transiting planet candidate by the HATSouth, WASP, and TESS surveys, and we present a combined analysis of all of the data gathered by each of these projects (and their follow-up programs). An exceptionally precise mass is measured for HATS-72b thanks to high-precision radial velocity (RV) measurements obtained with VLT/ESPRESSO, FEROS, HARPS, and Magellan/PFS. We also incorporate TESS observations of the warm Saturn-hosting systems HATS-47 (a.k.a. TOI1073.01), HATS-48A, and HATS-49. HATS-47 was independently identified as a candidate by the TESS team, while the other two systems were not previously identified from the TESS data. The RV orbital variations are measured for these systems using Magellan/PFS. HATS-48A has a resolved 5.4" neighbor in Gaia DR2, which is a common-proper-motion binary star companion to HATS-48A with a mass of 0.22M_{odot}_ and a current projected physical separation of ~1400au.
- ID:
- ivo://CDS.VizieR/J/A+A/640/A73
- Title:
- pi Men radial velocity curves
- Short Name:
- J/A+A/640/A73
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Measuring the geometry of multi-planet extrasolar systems can provide insight into their dynamical history and the processes of planetary formation. These types of measurements are challenging for systems that are detected through indirect techniques such as radial velocity and transit, having only been measured for a handful of systems to date. We aim to place constraints on the orbital geometry of the outer planet in the {pi} Mensae system, a G0V star at a distance of 18.3pc that is host to a wide-orbit super-Jovian (Msini=10.02+/-0.15M_Jup_) with a 5.7-year period and an inner transiting super-Earth (M=4.82+/-0.85M_{Earth}_) with a 6.3-d period. The reflex motion induced by the outer planet on the Mensae star causes a significant motion of the photocenter of the system on the sky plane over the course of the 5.7-year orbital period of the planet. We combined astrometric measurements from the Hipparcos and Gaia satellites with a precisely determined spectroscopic orbit in an attempt to measure this reflex motion, and in turn we constrained the inclination of the orbital plane of the outer planet. We measure an inclination of i_b_=49.9^+5.3^_-4.5_deg for the orbital plane of {pi} Mensae b, leading to a direct measurement of its mass of 13:01^+1.03^_-0.95_M_{Jup}_. We find a significant mutual inclination between the orbital planes of the two planets, with a 95% credible interval for i_mut_ of between 34.5{deg} and 140.6{deg} after accounting for the unknown position angle of the orbit of {pi} Mensae c, strongly excluding a co-planar scenario for the two planets within this system. All orbits are stable in the present-day configuration, and secular oscillations of planet c's eccentricity are quenched by general relativistic precession. Planet c may have undergone high eccentricity tidal migration triggered by Kozai-Lidov cycles, but dynamical histories involving disk migration or in situ formation are not ruled out. Nonetheless, this system provides the first piece of direct evidence that giant planets with large mutual inclinations have a role to play in the origins and evolution of some super-Earth systems.
- ID:
- ivo://CDS.VizieR/J/A+A/642/A31
- Title:
- pi Men radial velocity curves
- Short Name:
- J/A+A/642/A31
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The bright star {pi} Men was chosen as the first target for a radial velocity follow-up to test the performance of ESPRESSO, the new high-resolution spectrograph at the ESO's Very-Large Telescope (VLT). The star hosts a multi-planet system (a transiting 4M_{earth}_ planet at ~0.07au, and a sub-stellar companion on a ~2100-day eccentric orbit) which is particularly appealing for a precise multi-technique characterization. With the new ESPRESSO observations, that cover a time span of 200days, we aim to improve the precision and accuracy of the planet parameters and search for additional low-mass companions. We also take advantage of new photometric transits of {pi} Men c observed by TESS over a time span that overlaps with that of the ESPRESSO follow-up campaign. We analyse the enlarged spectroscopic and photometric datasets and compare the results to those in the literature. We further characterize the system by means of absolute astrometry with Hipparcos and Gaia. We used the high-resolution spectra of ESPRESSO for an independent determination of the stellar fundamental parameters. We present a precise characterization of the planetary system around {pi} Men. The ESPRESSO radial velocities alone (37 nightly binned data with typical uncertainty of 10cm/s) allow for a precise retrieval of the Doppler signal induced by {pi} Men c. The residuals show an RMS of 1.2m/s, which is half that of the HARPS data and, based on them, we put limits on the presence of additional low-mass planets (e.g. we can exclude companions with a minimum mass less than ~2M_{earth}_ within the orbit of {pi} Men c). We improve the ephemeris of {pi} Men c using 18 additional TESS transits, and in combination with the astrometric measurements, we determine the inclination of the orbital plane of {pi} Men b with high precision (i_b_=45.8^+1.4^_-1.1_deg). This leads to the precise measurement of its absolute mass m_b_=14.1^+0.5^_-0.4_Mjup, indicating that {pi} Men b can be classified as a brown dwarf. {pi} Men represents a nice example of the extreme precision radial velocities that can be obtained with ESPRESSO for bright targets. Our determination of the 3-D architecture of the {pi} Men planetary system, and the high relative misalignment of the planetary orbital planes, put constraints and challenges to the theories of formation and dynamical evolution of planetary systems. The accurate measurement of the mass of {pi} Men b contributes to make the brown dwarf desert a bit greener.
- ID:
- ivo://CDS.VizieR/J/A+A/619/L10
- Title:
- pi Men radial velocity curves
- Short Name:
- J/A+A/619/L10
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We report on the confirmation and mass determination of {pi} Men c, the first transiting planet discovered by NASA's TESS space mission. {pi} Men is a naked-eye (V=5.65mag), quiet G0 V star that was previously known to host a sub-stellar companion ({pi} Men b) on a longperiod (Porb=2091-days), eccentric (e=0.64) orbit. Using TESS time-series photometry, combined with Gaia data, published UCLES at AAT Doppler measurements, and archival HARPS at ESO-3.6m radial velocities, we found that {pi} Men c is a close-in planet with an orbital period of Porb=6.27-days, a mass of Mc=4.52+/-0.81M_{Earth}_, and a radius of Rc=2.06+/-0.03R_{Earth}_. Based on the planet's orbital period and size, {pi} Men c is a super-Earth located at, or close to, the radius gap, while its mass and bulk density suggest it may have held on to a significant atmosphere. Because of the brightness of the host star, this system is highly suitable for a wide range of further studies to characterize the planetary atmosphere and dynamical properties. We also performed an asteroseismic analysis of the TESS data and detected a hint of power excess consistent with the seismic values expected for this star, although this result depends on the photometric aperture used to extract the light curve. This marginal detection is expected from pre-launch simulations hinting at the asteroseismic potential of the TESS mission for longer, multi-sector observations and/or for more evolved bright stars.
- ID:
- ivo://CDS.VizieR/J/AJ/156/22
- Title:
- Planetary candidates from K2 Campaign 16
- Short Name:
- J/AJ/156/22
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Given that Campaign 16 of the K2 mission is one of just two K2 campaigns observed so far in "forward-facing" mode, which enables immediate follow-up observations from the ground, we present a catalog of interesting targets identified through photometry alone. Our catalog includes 30 high-quality planet candidates (showing no signs of being non-planetary in nature), 48 more ambiguous events that may be either planets or false positives, 164 eclipsing binaries, and 231 other regularly periodic variable sources. We have released light curves for all targets in C16 and have also released system parameters and transit vetting plots for all interesting candidates identified in this paper. Of particular interest is a candidate planet orbiting the bright F dwarf HD 73344 (V=6.9, K=5.6) with an orbital period of 15 days. If confirmed, this object would correspond to a 2.56+/-0.18 R_{Earth}_ planet and would likely be a favorable target for radial velocity characterization. This paper is intended as a rapid release of planet candidates, eclipsing binaries, and other interesting periodic variables to maximize the scientific yield of this campaign, and as a test run for the upcoming TESS mission, whose frequent data releases call for similarly rapid candidate identification and efficient follow up.
- ID:
- ivo://CDS.VizieR/J/ApJS/244/11
- Title:
- Planet candidates and EBs in K2 campaigns 0-8
- Short Name:
- J/ApJS/244/11
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We implement a search for exoplanets in campaigns zero through eight (C0-8) of the K2 extension of the Kepler spacecraft. We apply a modified version of the Quasi-periodic Automated Transit Search (QATS) planet search algorithm to K2 light curves produced by the EVEREST pipeline, carrying out the C0-8 search on 1.5x10^5^ target stars with magnitudes in the range of Kp=9-15. We detect 818 transiting planet candidates, of which 374 were undiscovered by prior searches, with {64, 15, 5, 2, 1} in {2, 3, 4, 5, 6}-planet multiplanet candidate systems, respectively. Of the new planets detected, 100 orbit M dwarfs, including one that is potentially rocky and in the habitable zone. A total of 154 of our candidates reciprocally transit with our solar system: they are geometrically aligned to see at least one solar system planet transit. We find candidates that display transit timing variations and dozens of candidates on both period extremes with single transits or ultrashort periods. We point to evidence that our candidates display similar patterns in frequency and size-period relation to confirmed planets, such as tentative evidence for the radius gap. Confirmation of these planet candidates with follow-up studies will increase the number of K2 planets by up to 50%, and characterization of their host stars will improve statistical studies of planet properties. Our sample includes many planets orbiting bright stars amenable for radial velocity follow-up and future characterization with JWST. We also list the 579 eclipsing binary systems detected as part of this search.
