- ID:
- ivo://CDS.VizieR/J/ApJ/829/L9
- Title:
- K2 LC of HD 3167 and Robo-AO image
- Short Name:
- J/ApJ/829/L9
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We report the discovery of two super-Earth-sized planets transiting the bright (V=8.94, K=7.07) nearby late G-dwarf HD 3167, using data collected by the K2 mission. The inner planet, HD 3167 b, has a radius of 1.6R_{Earth}_ and an ultra-short orbital period of only 0.96d. The outer planet, HD 3167 c, has a radius of 2.9R_{Earth}_ and orbits its host star every 29.85 days. At a distance of just 45.8+/-2.2pc, HD3167 is one of the closest and brightest stars hosting multiple transiting planets, making HD 3167 b and c well suited for follow-up observations. The star is chromospherically inactive with low rotational line-broadening, ideal for radial velocity observations to measure the planets' masses. The outer planet is large enough that it likely has a thick gaseous envelope that could be studied via transmission spectroscopy. Planets transiting bright, nearby stars like HD 3167 are valuable objects to study leading up to the launch of the James Webb Space Telescope.
Number of results to display per page
Search Results
- ID:
- ivo://CDS.VizieR/J/A+A/594/A100
- Title:
- K2 new planetary and EB candidates
- Short Name:
- J/A+A/594/A100
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- With only two functional reaction wheels, Kepler cannot maintain stable pointing at its original target field and has entered a new mode of observation called K2. We describe a new pipeline to reduce K2 pixel files into light curves that are later searched for transit like features. Our method is based on many years of experience in planet hunting for the CoRoT mission. Owing to the unstable pointing, K2 light curves present systematics that are correlated with the target position in the ccd. Therefore, our pipeline also includes a decorrelation of this systematic noise. Our pipeline is optimised for bright stars for which spectroscopic follow-up is possible. We achieve a maximum precision on 6 hours of 6 ppm. The decorrelated light curves are searched for transits with an adapted version of the CoRoT alarm pipeline. We present 172 planetary candidates and 327 eclipsing binary candidates from campaigns 1, 2, 3, 4, 5, and 6 of K2. Both the planetary candidates and eclipsing binary candidates lists are made public to promote follow-up studies. The light curves will also be available to the community.
- ID:
- ivo://CDS.VizieR/J/AJ/153/117
- Title:
- KOIs companions from high-resolution imaging
- Short Name:
- J/AJ/153/117
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We report on 176 close (<2'') stellar companions detected with high-resolution imaging near 170 hosts of Kepler Objects of Interest (KOIs). These Kepler targets were prioritized for imaging follow-up based on the presence of small planets, so most of the KOIs in these systems (176 out of 204) have nominal radii <6R_{Earth}_. Each KOI in our sample was observed in at least two filters with adaptive optics, speckle imaging, lucky imaging, or the Hubble Space Telescope. Multi-filter photometry provides color information on the companions, allowing us to constrain their stellar properties and assess the probability that the companions are physically bound. We find that 60%-80% of companions within 1'' are bound, and the bound fraction is >90% for companions within 0.5''; the bound fraction decreases with increasing angular separation. This picture is consistent with simulations of the binary and background stellar populations in the Kepler field. We also reassess the planet radii in these systems, converting the observed differential magnitudes to a contamination in the Kepler bandpass and calculating the planet radius correction factor, X_R_=R_p_(true)/R_p_(single). Under the assumption that planets in bound binaries are equally likely to orbit the primary or secondary, we find a mean radius correction factor for planets in stellar multiples of X_R_=1.65. If stellar multiplicity in the Kepler field is similar to the solar neighborhood, then nearly half of all Kepler planets may have radii underestimated by an average of 65%, unless vetted using high-resolution imaging or spectroscopy.
- ID:
- ivo://CDS.VizieR/J/ApJ/821/47
- Title:
- KOI transit probabilities of multi-planet syst.
- Short Name:
- J/ApJ/821/47
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- NASA's Kepler Space Telescope has successfully discovered thousands of exoplanet candidates using the transit method, including hundreds of stars with multiple transiting planets. In order to estimate the frequency of these valuable systems, it is essential to account for the unique geometric probabilities of detecting multiple transiting extrasolar planets around the same parent star. In order to improve on previous studies that used numerical methods, we have constructed an efficient, semi-analytical algorithm called the Computed Occurrence of Revolving Bodies for the Investigation of Transiting Systems (CORBITS), which, given a collection of conjectured exoplanets orbiting a star, computes the probability that any particular group of exoplanets can be observed to transit. The algorithm applies theorems of elementary differential geometry to compute the areas bounded by circular curves on the surface of a sphere. The implemented algorithm is more accurate and orders of magnitude faster than previous algorithms, based on comparisons with Monte Carlo simulations. We use CORBITS to show that the present solar system would only show a maximum of three transiting planets, but that this varies over time due to dynamical evolution. We also used CORBITS to geometrically debias the period ratio and mutual Hill sphere distributions of Kepler's multi-transiting planet candidates, which results in shifting these distributions toward slightly larger values. In an Appendix, we present additional semi-analytical methods for determining the frequency of exoplanet mutual events, i.e., the geometric probability that two planets will transit each other (planet-planet occultation, relevant to transiting circumbinary planets) and the probability that this transit occurs simultaneously as they transit their star.
- ID:
- ivo://CDS.VizieR/J/A+A/564/A33
- Title:
- KOI-676 transits for planets b and c
- Short Name:
- J/A+A/564/A33
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We report the detection and characterization of two short-period, Neptune-sized planets around the active host star Kepler-210. The host star's parameters derived from those planets are (a) mutually inconsistent and (b) do not conform to the expected host star parameters. We furthermore report the detection of transit timing variations (TTVs) in the O-C diagrams for both planets. We explore various scenarios that explain and resolve those discrepancies. A simple scenario consistent with all data appears to be one that attributes substantial eccentricities to the inner short-period planets and that interprets the TTVs as due to the action of another, somewhat longer period planet. To substantiate our suggestions, we present the results of N-body simulations that modeled the TTVs and that checked the stability of the Kepler-210 system.
- ID:
- ivo://CDS.VizieR/J/A+A/608/A93
- Title:
- K2-106 radial velocities measurements
- Short Name:
- J/A+A/608/A93
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Planets in the mass range from 2 to 15M_{Erath}_ are very diverse. Some of them have low densities, while others are very dense. By measuring the masses and radii, the mean densities, structure, and composition of the planets are constrained. These parameters also give us important information about their formation and evolution, and about possible processes for atmospheric loss. We determined the masses, radii, and mean densities for the two transiting planets orbiting K2-106. The inner planet has an ultra-short period of 0.57 days. The period of the outer planet is 13.3 days.
- ID:
- ivo://CDS.VizieR/J/ApJ/707/1707
- Title:
- Ks-band light curve of CoRoT-1b
- Short Name:
- J/ApJ/707/1707
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We report the detection in Ks-band of the secondary eclipse of the hot Jupiter CoRoT-1b from time series photometry with the ARC 3.5m telescope at Apache Point Observatory. The eclipse shows a depth of 0.336+/-0.042% and is centered at phase 0.5022^+0.0023^_-0.0027_, consistent with a zero eccentricity orbit (e*cos{omega}=0.0035^+0.0036^_-0.0042_). We perform the first optical to near-infrared multi-band photometric analysis of an exoplanet's atmosphere and constrain the reflected and thermal emissions by combining our result with the recent 0.6, 0.71, and 2.09um secondary eclipse detections by Snellen et al. (2009Natur.459..543S), Gillon et al. (2009, J/A+A/506/359), and Alonso et al. (2009A&A...501L..23A). Comparing the multi-wavelength detections to state-of-the-art radiative-convective chemical-equilibrium atmosphere models, we find the near-infrared fluxes difficult to reproduce. The closest blackbody-based and physical models provide the following atmosphere parameters: a temperature T=2460^+80^_-160_K; a very low Bond albedo A_B_=0.000^+0.081^_-0.000_; and an energy redistribution parameter P_n_=0.1, indicating a small but nonzero amount of heat transfer from the day to nightside. The best physical model suggests a thermal inversion layer with an extra optical absorber of opacity {kappa}_e_=0.05cm^2^/g, placed near the 0.1 bar atmospheric pressure level. This inversion layer is located 10 times deeper in the atmosphere than the absorbers used in models to fit mid-infrared Spitzer detections of other irradiated hot Jupiters.
- ID:
- ivo://CDS.VizieR/J/A+A/550/A54
- Title:
- Ks-band observations of WASP-33b
- Short Name:
- J/A+A/550/A54
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- In recent years, day-side emission from about a dozen hot Jupiters has been detected through ground-based secondary eclipse observations in the near-infrared. These near-infrared observations are vital for determining the energy budgets of hot Jupiters, since they probe the planet-spectral energy distribution near its peak. The aim of this work is to measure the Ks -band secondary eclipse depth of WASP-33b, the first planet discovered to transit an A-type star. This planet receives the highest level of irradiation of all transiting planets discovered to date. Furthermore, its host-star shows pulsations and is classified as a low-amplitude delta-Scuti. As part of our GROUnd-based Secondary Eclipse (GROUSE) project we have obtained observations of two separate secondary eclipses of WASP-33b in the Ks-band using the LIRIS instrument on the William Herschel Telescope (WHT). The telescope was significantly defocused to avoid saturation of the detector for this bright star (K~7.5). To increase the stability and the cadence of the observations, they were performed in staring mode. We collected a total of 5100 and 6900 frames for the first and the second night respectively, both with an average cadence of 3.3 seconds. On the second night the eclipse is detected at the 12-sigma level, with a measured eclipse depth of 0.244_-020_^+0.027^%. This eclipse depth corresponds to a brightness temperature of 3270_-160^+115^K. The measured brightness temperature on the second night is consistent with the expected equilibrium temperature for a planet with a very low albedo and a rapid re-radiation of the absorbed stellar light. For the other night the short out-of-eclipse baseline prevents good corrections for the stellar pulsations and systematic effects, which makes this dataset unreliable for eclipse depth measurements. This demonstrates the need of getting a sufficient out-of-eclipse baseline.
- ID:
- ivo://CDS.VizieR/J/A+A/615/A69
- Title:
- K2-3 system characterized with HARPS-N & HARPS
- Short Name:
- J/A+A/615/A69
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- M-dwarf stars are promising targets for identifying and characterizing potentially habitable planets. K2-3 is a nearby (45pc), early-type M dwarf hosting three small transiting planets, the outermost of which orbits close to the inner edge of the stellar (optimistic) habitable zone. The K2-3 system is well suited for follow-up characterization studies aimed at determining accurate masses and bulk densities of the three planets. Using a total of 329 radial velocity measurements collected over 2.5 years with the HARPS-N and HARPS spectrographs and a proper treatment of the stellar activity signal, we aim to improve measurements of the masses and bulk densities of the K2-3 planets. We use our results to investigate the physical structure of the planets. We analysed radial velocity time series extracted with two independent pipelines using Gaussian process regression. We adopted a quasi-periodic kernel to model the stellar magnetic activity jointly with the planetary signals. We used Monte Carlo simulations to investigate the robustness of our mass measurements of K2-3 c and K2-3 d, and to explore how additional high-cadence radial velocity observations might improve these values. Even though the stellar activity component is the strongest signal present in the radial velocity time series, we are able to derive masses for both planet b (Mb=6.6+/-1.1M_{Earth}_) and planet c (Mc=3.1^+1.3^_-1.2_M_{Earth}_). The Doppler signal from K2-3 d remains undetected, likely because of its low amplitude compared to the radial velocity signal induced by the stellar activity. The closeness of the orbital period of K2-3 d to the stellar rotation period could also make the detection of the planetary signal complicated. Based on our ability to recover injected signals in simulated data, we tentatively estimate the mass of K2-3 d to be Md=2.7^+1.2^_-0.8_M_{Earth}_. These mass measurements imply that the bulk densities and therefore the interior structures of the three planets may be similar. In particular, the planets may either have small H/He envelopes (<1percent) or massive water layers, with a water content >50 percent of their total mass, on top of rocky cores. Placing further constraints on the bulk densities of K2-3 c and d is difficult; in particular, we would not have been able to detect the Doppler signal of K2-3 d even by adopting a semester of intense, high-cadence radial velocity observations with HARPS-N and HARPS.
- ID:
- ivo://CDS.VizieR/J/ApJ/809/42
- Title:
- LC and RV data of PTFO 8-8695 T-Tauri star
- Short Name:
- J/ApJ/809/42
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present Spitzer 4.5{mu}m light curve observations, Keck NIRSPEC radial velocity observations, and LCOGT optical light curve observations of PTFO 8-8695, which may host a Jupiter-sized planet in a very short orbital period (0.45 days). Previous work by van Eyken et al. (2012ApJ...755...42V) and Barnes et al. (2013ApJ...774...53B) predicts that the stellar rotation axis and the planetary orbital plane should precess with a period of 300-600 days. As a consequence, the observed transits should change shape and depth, disappear, and reappear with the precession. Our observations indicate the long-term presence of the transit events (>3 years), and that the transits indeed do change depth, disappear and reappear. The Spitzer observations and the NIRSPEC radial velocity observations (with contemporaneous LCOGT optical light curve data) are consistent with the predicted transit times and depths for the M*=0.34M_{sun}_ precession model and demonstrate the disappearance of the transits. An LCOGT optical light curve shows that the transits do reappear approximately 1 year later. The observed transits occur at the times predicted by a straight-forward propagation of the transit ephemeris. The precession model correctly predicts the depth and time of the Spitzer transit and the lack of a transit at the time of the NIRSPEC radial velocity observations. However, the precession model predicts the return of the transits approximately 1 month later than observed by LCOGT. Overall, the data are suggestive that the planetary interpretation of the observed transit events may indeed be correct, but the precession model and data are currently insufficient to confirm firmly the planetary status of PTFO 8-8695b.