- ID:
- ivo://CDS.VizieR/J/A+A/587/A57
- Title:
- HR 8799e and HR 8799d spectra
- Short Name:
- J/A+A/587/A57
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The planetary system discovered around the young A-type HR 8799 provides a unique laboratory to: a) test planet formation theories; b) probe the diversity of system architectures at these separations, and c) perform comparative (exo)planetology. We present and exploit new near-infrared images and integral-field spectra of the four gas giants surrounding HR 8799 obtained with SPHERE, the new planet finder instrument at the Very Large Telescope, during the commissioning and science verification phase of the instrument (July-December 2014). With these new data, we contribute to completing the spectral energy distribution (SED) of these bodies in the 1.0-2.5um range. We also provide new astrometric data, in particular for planet e, to further constrain the orbits. We used the infrared dual-band imager and spectrograph (IRDIS) subsystem to obtain pupil-stabilized, dual-band H2H3 (1.593um, 1.667um), K1K2 (2.110um, 2.251um), and broadband J (1.245um) images of the four planets. IRDIS was operated in parallel with the integral field spectrograph (IFS) of SPHERE to collect low-resolution (R~30), near-infrared (0.94-1.64um) spectra of the two innermost planets HR 8799 d and e. The data were reduced with dedicated algorithms, such as the Karhunen-Loeve image projection (KLIP), to reveal the planets. We used the so-called negative planets injection technique to extract their photometry, spectra, and measure their positions. We illustrate the astrometric performance of SPHERE through sample orbital fits compatible with SPHERE and literature data.
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Search Results
- ID:
- ivo://CDS.VizieR/J/A+A/476/1347
- Title:
- HST/ACS flux time series for HD 189733
- Short Name:
- J/A+A/476/1347
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We monitored three transits of the giant gas planet around the nearby K dwarf HD 189733 with the ACS camera on the Hubble Space Telescope. The resulting very-high accuracy light-curve (signal-to-noise ratio near 15000 on individual measurements, 35000 on 10-min averages) allows a direct geometric measurement of the orbital inclination, radius ratio and scale of the system: i=85.68+/-0.04, Rpl/R*=0.1572+/-0.0004, a/R*=8.92+/-0.09.
- ID:
- ivo://CDS.VizieR/J/A+A/486/1039
- Title:
- HST transit light curve for GJ436b
- Short Name:
- J/A+A/486/1039
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present time series photometry for six partial transits of GJ 436b obtained with the Fine Guidance Sensor instrument on the Hubble Space Telescope (HST).
- ID:
- ivo://CDS.VizieR/J/ApJ/818/176
- Title:
- HST/WFC3 NIR photometry of 2M1207b
- Short Name:
- J/ApJ/818/176
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Rotational modulations of brown dwarfs have recently provided powerful constraints on the properties of ultra-cool atmospheres, including longitudinal and vertical cloud structures and cloud evolution. Furthermore, periodic light curves directly probe the rotational periods of ultra-cool objects. We present here, for the first time, time-resolved high-precision photometric measurements of a planetary-mass companion, 2M1207b. We observed the binary system with Hubble Space Telescope/Wide Field Camera 3 in two bands and with two spacecraft roll angles. Using point-spread function-based photometry, we reach a nearly photon-noise limited accuracy for both the primary and the secondary. While the primary is consistent with a flat light curve, the secondary shows modulations that are clearly detected in the combined light curve as well as in different subsets of the data. The amplitudes are 1.36% in the F125W and 0.78% in the F160W filters, respectively. By fitting sine waves to the light curves, we find a consistent period of 10.7_-0.6_^+1.2^hr and similar phases in both bands. The J- and H-band amplitude ratio of 2M1207b is very similar to a field brown dwarf that has identical spectral type but different J-H color. Importantly, our study also measures, for the first time, the rotation period for a directly imaged extra-solar planetary-mass companion.
- ID:
- ivo://CDS.VizieR/J/ApJ/747/35
- Title:
- HST/WFC3 transit observation of GJ1214b
- Short Name:
- J/ApJ/747/35
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Capitalizing on the observational advantage offered by its tiny M dwarf host, we present Hubble Space Telescope/Wide Field Camera 3 (WFC3) grism measurements of the transmission spectrum of the super-Earth exoplanet GJ1214b. These are the first published WFC3 observations of a transiting exoplanet atmosphere. After correcting for a ramp-like instrumental systematic, we achieve nearly photon-limited precision in these observations, finding the transmission spectrum of GJ1214b to be flat between 1.1 and 1.7{mu}m. Inconsistent with a cloud-free solar composition atmosphere at 8.2{sigma}, the measured achromatic transit depth most likely implies a large mean molecular weight for GJ1214b's outer envelope. A dense atmosphere rules out bulk compositions for GJ1214b that explain its large radius by the presence of a very low density gas layer surrounding the planet. High-altitude clouds can alternatively explain the flat transmission spectrum, but they would need to be optically thick up to 10 mbar or consist of particles with a range of sizes approaching 1 {mu}m in diameter.
- ID:
- ivo://CDS.VizieR/J/MNRAS/448/1118
- Title:
- HU Aqr planetary system mid-egress moments
- Short Name:
- J/MNRAS/448/1118
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We study the mid-egress eclipse timing data gathered for the cataclysmic binary HU Aquarii during the years 1993-2014. The (O-C) residuals were previously attributed to a single ~7 Jupiter mass companion in ~5 AU orbit or to a stable two-planet system with an unconstrained outermost orbit. We present 22 new observations gathered between 2011 June and 2014 July with four instruments around the world. They reveal a systematic deviation of ~60-120 s from the older ephemeris. We re-analyse the whole set of the timing data available. Our results provide an erratum to the previous HU Aqr planetary models, indicating that the hypothesis for a third and fourth body in this system is uncertain. The dynamical stability criterion and a particular geometry of orbits rule out coplanar two-planet configurations. A putative HU Aqr planetary system may be more complex, e.g. highly non-coplanar. Indeed, we found examples of three-planet configurations with the middle planet in a retrograde orbit, which are stable for at least 1 Gyr, and consistent with the observations. The (O-C) may be also driven by oscillations of the gravitational quadrupole moment of the secondary, as predicted by the Lanza et al. modification of the Applegate mechanism. Further systematic, long-term monitoring of HU Aqr is required to interpret the (O-C) residuals.
- ID:
- ivo://CDS.VizieR/J/ApJS/215/21
- Title:
- Hydrogen and Helium EOS in brown dwarfs
- Short Name:
- J/ApJS/215/21
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present new equations of state (EOSs) for hydrogen and helium covering a wide range of temperatures from 60K to 10^7^K and densities from 10^-10^g/cm^3^ to 10^3^g/cm^3^. They include an extended set of ab initio EOS data for the strongly correlated quantum regime with an accurate connection to data derived from other approaches for the neighboring regions. We compare linear mixing isotherms based on our EOS tables with available real mixture data. A first important astrophysical application of this new EOS data is the calculation of interior models for Jupiter and comparison with recent results. Second, mass-radius relations are calculated for Brown Dwarfs (BDs) which we compare with predictions derived from the widely used EOS of Saumon, Chabrier, and van Horn. Furthermore, we calculate interior models for typical BDs with different masses, namely, Corot-3b, Gliese-229b, and Corot-15b, and the giant planet KOI-889b. The predictions for the central pressures and densities differ by up to 10% dependent on the EOS used.
- ID:
- ivo://CDS.VizieR/J/ApJ/720/1118
- Title:
- i-band photometry of HAT-P-16
- Short Name:
- J/ApJ/720/1118
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We report the discovery of HAT-P-16b, a transiting extrasolar planet orbiting the V=10.8mag F8 dwarf GSC 2792-01700, with a period P=2.775960+/-0.000003 days, transit epoch T_c_=2455027.59293+/-0.00031 (BJD10), and transit duration 0.1276+/-0.0013 days. The host star has a mass of 1.22+/-0.04M_{sun}_, radius of 1.24+/-0.05R_{sun}_, effective temperature 6158+/-80K, and metallicity [Fe/H]=+0.17+/-0.08. The planetary companion has a mass of 4.193+/-0.094M_J_ and radius of 1.289+/-0.066R_J_, yielding a mean density of 2.42+/-0.35g/cm^3^. Comparing these observed characteristics with recent theoretical models, we find that HAT-P-16b is consistent with a 1Gyr H/He-dominated gas giant planet. HAT-P-16b resides in a sparsely populated region of the mass-radius diagram and has a non-zero eccentricity of e=0.036 with a significance of 10{sigma}.
- ID:
- ivo://CDS.VizieR/J/AJ/152/108
- Title:
- i filter photometry for HATS-25 through HATS-30
- Short Name:
- J/AJ/152/108
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We report six new inflated hot Jupiters (HATS-25b through HATS-30b) discovered using the HATSouth global network of automated telescopes. The planets orbit stars with V magnitudes in the range of ~12-14 and have masses in the largely populated 0.5M_J_--0.7M_J_ region of parameter space but span a wide variety of radii, from 1.17R_J_ to 1.75R_J_. HATS-25b, HATS-28b, HATS-29b, and HATS-30b are typical inflated hot Jupiters (R_p_=1.17--1.26R_J_) orbiting G-type stars in short period (P=3.2-4.6 days) orbits. However, HATS-26b (R_p_=1.75R_J_, P=3.3024days) and HATS-27b (R_p_=1.50R_J_, P=4.6370days) stand out as highly inflated planets orbiting slightly evolved F stars just after and in the turn-off points, respectively, which are among the least dense hot Jupiters, with densities of 0.153g/cm^3^ and 0.180g/cm^3^, respectively. All the presented exoplanets but HATS-27b are good targets for future atmospheric characterization studies, while HATS-27b is a prime target for Rossiter-McLaughlin monitoring in order to determine its spin-orbit alignment given the brightness (V=12.8) and stellar rotational velocity (vsini~9.3km/s) of the host star. These discoveries significantly increase the number of inflated hot Jupiters known, contributing to our understanding of the mechanism(s) responsible for hot Jupiter inflation.
- ID:
- ivo://CDS.VizieR/J/ApJ/767/95
- Title:
- Improved stellar parameters of smallest KIC stars
- Short Name:
- J/ApJ/767/95
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We use the optical and near-infrared photometry from the Kepler Input Catalog to provide improved estimates of the stellar characteristics of the smallest stars in the Kepler target list. We find 3897 dwarfs with temperatures below 4000K, including 64 planet candidate host stars orbited by 95 transiting planet candidates. We refit the transit events in the Kepler light curves for these planet candidates and combine the revised planet/star radius ratios with our improved stellar radii to revise the radii of the planet candidates orbiting the cool target stars. We then compare the number of observed planet candidates to the number of stars around which such planets could have been detected in order to estimate the planet occurrence rate around cool stars. We find that the occurrence rate of 0.5-4R_{oplus}_ planets with orbital periods shorter than 50 days is 0.90_0.03_^0.04^ planets per star. The occurrence rate of Earth-size (0.5-1.4R_{oplus}_) planets is constant across the temperature range of our sample at 0.51_0.05_^0.06^ Earth-size planets per star, but the occurrence of 1.4-4R_{oplus}_ planets decreases significantly at cooler temperatures. Our sample includes two Earth-size planet candidates in the habitable zone, allowing us to estimate that the mean number of Earth-size planets in the habitable zone is 0.15_0.06_^0.13^ planets per cool star. Our 95% confidence lower limit on the occurrence rate of Earth-size planets in the habitable zones of cool stars is 0.04 planets per star. With 95% confidence, the nearest transiting Earth-size planet in the habitable zone of a cool star is within 21pc. Moreover, the nearest non-transiting planet in the habitable zone is within 5pc with 95% confidence.