- 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.
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Search Results
- ID:
- ivo://CDS.VizieR/J/AJ/152/8
- Title:
- Impact of stellar multiplicity on planetary systems I.
- Short Name:
- J/AJ/152/8
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The dynamical influence of binary companions is expected to profoundly influence planetary systems. However, the difficulty of identifying planets in binary systems has left the magnitude of this effect uncertain; despite numerous theoretical hurdles to their formation and survival, at least some binary systems clearly host planets. We present high-resolution imaging of 382 Kepler Objects of Interest (KOIs) obtained using adaptive-optics imaging and nonredundant aperture-mask interferometry on the Keck II telescope. Among the full sample of 506 candidate binary companions to KOIs, we super-resolve some binary systems to projected separations of <5au, showing that planets might form in these dynamically active environments. However, the full distribution of projected separations for our planet-host sample more broadly reveals a deep paucity of binary companions at solar-system scales. For a field binary population, we should have found 58 binary companions with projected separation {rho}<50au and mass ratio q>0.4; we instead only found 23 companions (a 4.6{sigma} deficit), many of which must be wider pairs that are only close in projection. When the binary population is parametrized with a semimajor axis cutoff a_cut_ and a suppression factor inside that cutoff S_bin_, we find with correlated uncertainties that inside a_cut_=47_-23_^+59^au, the planet occurrence rate in binary systems is only S_bin_=0.34_-0.15_^+0.14^ times that of wider binaries or single stars. Our results demonstrate that a fifth of all solar-type stars in the Milky Way are disallowed from hosting planetary systems due to the influence of a binary companion.
- 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.
- ID:
- ivo://CDS.VizieR/J/ApJ/714/462
- Title:
- Inclination change of TrES-2b
- Short Name:
- J/ApJ/714/462
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- On 2009 June 15 UT the transit of TrES-2b was detected using the University of Arizona's 1.55m Kuiper Telescope with 2.0-2.5 millimag rms accuracy in the I band. We find a central transit time of T_c_=2454997.76286+/-0.00035HJD, an orbital period of P=2.4706127+/-0.0000009 days, and an inclination angle of i=83.92{deg}+/-0.05{deg}, which is consistent with our re-fit of the original I-band light curve of O'Donovan et al. where we find i=83.84{deg}+/-0.05{deg}. We calculate an insignificant inclination change of {Delta}i =-0.08{deg}+/-0.07{deg} over the last three years, and as such, our observations rule out, at the ~11{sigma} level, the apparent change of orbital inclination to i_predicted_=83.35{deg}+/-0.1{deg} as predicted by Mislis & Schmitt and Mislis et al. for our epoch. Moreover, our analysis of a recently published Kepler Space Telescope light curve for TrES-2b finds an inclination of i=83.91{deg}+/-0.03{deg} for a similar epoch. These Kepler results definitively rule out change in i as a function of time. Indeed, we detect no significant changes in any of the orbital parameters of TrES-2b.
- ID:
- ivo://CDS.VizieR/J/MNRAS/474/2094
- Title:
- Inferring probabilistic stellar rotation periods
- Short Name:
- J/MNRAS/474/2094
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Variability in the light curves of spotted, rotating stars is often non-sinusoidal and quasi-periodic - spots move on the stellar surface and have finite lifetimes, causing stellar flux variations to slowly shift in phase. A strictly periodic sinusoid therefore cannot accurately model a rotationally modulated stellar light curve. Physical models of stellar surfaces have many drawbacks preventing effective inference, such as highly degenerate or high-dimensional parameter spaces. In this work, we test an appropriate effective model: a Gaussian Process with a quasi-periodic covariance kernel function. This highly flexible model allows sampling of the posterior probability density function of the periodic parameter, marginalizing over the other kernel hyperparameters using a Markov Chain Monte Carlo approach. To test the effectiveness of this method, we infer rotation periods from 333 simulated stellar light curves, demonstrating that the Gaussian process method produces periods that are more accurate than both a sine-fitting periodogram and an autocorrelation function method. We also demonstrate that it works well on real data, by inferring rotation periods for 275 Kepler stars with previously measured periods. We provide a table of rotation periods for these and many more, altogether 1102 Kepler objects of interest, and their posterior probability density function samples. Because this method delivers posterior probability density functions, it will enable hierarchical studies involving stellar rotation, particularly those involving population modelling, such as inferring stellar ages, obliquities in exoplanet systems, or characterizing star-planet interactions. The code used to implement this method is available online (https://github.com/RuthAngus/GProtation/).
- ID:
- ivo://CDS.VizieR/J/AJ/160/268
- Title:
- Infrared photometry of binaries in Orion OB1
- Short Name:
- J/AJ/160/268
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Statistics of low-mass pre-main-sequence binaries in the Orion OB1 association with separations ranging from 0.6" to 20" (220 to 7400au at 370pc) are studied using images from the VISTA Orion mini survey and astrometry from Gaia. The input sample based on the CVSO catalog contains 1137 stars of K and M spectral types (masses between 0.3 and 0.9M{odot}), 1021 of which are considered to be association members. There are 135 physical binary companions to these stars with mass ratios above ~0.13. The average companion fraction is 0.09{+/-}0.01 over 1.2 decades in separation, slightly less than, but still consistent with, the field. We found a difference between the Ori OB1a and OB1b groups, the latter being richer in binaries by a factor of 1.6{+/-}0.3. No overall dependence of the wide- binary frequency on the observed underlying stellar density is found, although in the Ori OB1a off-cloud population, these binaries seem to avoid dense clusters. The multiplicity rates in Ori OB1 and in sparse regions like Taurus differ significantly, hinting that binaries in the field may originate from a mixture of diverse populations.
- ID:
- ivo://CDS.VizieR/J/AJ/144/42
- Title:
- Infrared photometry of 90 KOIs
- Short Name:
- J/AJ/144/42
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- All transiting planets are at risk of contamination by blends with nearby, unresolved stars. Blends dilute the transit signal, causing the planet to appear smaller than it really is, or produce a false-positive detection when the target star is blended with eclipsing binary stars. This paper reports on high spatial-resolution adaptive optics images of 90 Kepler planetary candidates. Companion stars are detected as close as 0.1" from the target star. Images were taken in the near-infrared (J and Ks bands) with ARIES on the MMT and PHARO on the Palomar Hale 200inch telescope. Most objects (60%) have at least one star within 6" separation and a magnitude difference of 9. Eighteen objects (20%) have at least one companion within 2" of the target star; six companions (7%) are closer than 0.5". Most of these companions were previously unknown, and the associated planetary candidates should receive additional scrutiny. Limits are placed on the presence of additional companions for every system observed, which can be used to validate planets statistically using the BLENDER method. Validation is particularly critical for low-mass, potentially Earth-like worlds, which are not detectable with current-generation radial velocity techniques. High-resolution images are thus a crucial component of any transit follow-up program.
- ID:
- ivo://CDS.VizieR/J/AJ/162/183
- Title:
- Infrared spectra of V838 Monocerotis with SOFIA
- Short Name:
- J/AJ/162/183
- Date:
- 14 Mar 2022 06:37:38
- Publisher:
- CDS
- Description:
- Luminous Red Variables are most likely eruptions that are the outcome of stellar mergers. V838Mon is one of the best-studied members of this class, representing an archetype for stellar mergers resulting from B-type stars. As result of the merger event, "nova-like" eruptions occur driving mass loss from the system. As the gas cools considerable circumstellar dust is formed. V838Mon erupted in 2002 and is undergoing very dynamic changes in its dust composition, geometry, and infrared luminosity providing a real-time laboratory to validate mineralogical condensation sequences in stellar mergers and evolutionary scenarios. We discuss recent NASA Stratospheric Observatory for Infrared Astronomy 5-38{mu}m observations combined with archival NASA Spitzer spectra that document the temporal evolution of the freshly formed (within the last <~20yr) circumstellar material in the environs of V838Mon. Changes in the 10{mu}m spectral region are strong evidence that we are witnessing a classical dust condensation sequence expected to occur in oxygen-rich environments where alumina formation is followed by that of silicates at the temperature cools.
- ID:
- ivo://CDS.VizieR/J/ApJ/826/171
- Title:
- IR data of debris disk vs metallicity of stars
- Short Name:
- J/ApJ/826/171
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We find that the initial dust masses in planetary debris disks are correlated with the metallicities of their central stars. We compiled a large sample of systems, including Spitzer, the Herschel DUNES and DEBRIS surveys, and WISE debris disk candidates. We also merged 33 metallicity catalogs to provide homogeneous [Fe/H] and {sigma}_[Fe/H]_ values. We analyzed this merged sample, including 222 detected disks (74 warm and 148 cold) around a total of 187 systems (some with multiple components) and 440 disks with only upper limits (125 warm and 315 cold) around a total of 360 systems. The disk dust masses at a common early evolutionary point in time were determined using our numerical disk evolutionary code, evolving a unique model for each of the 662 disks backward to an age of 1Myr. We find that disk-bearing stars seldom have metallicities less than [Fe/H]=-0.2 and that the distribution of warm component masses lacks examples with large mass around stars of low metallicity ([Fe/H]<-0.085). Previous efforts to find a correlation have been largely unsuccessful; the primary improvements supporting our result are (1) basing the study on dust masses, not just infrared excess detections; (2) including upper limits on dust mass in a quantitative way; (3) accounting for the evolution of debris disk excesses as systems age; (4) accounting fully for the range of uncertainties in metallicity measurements; and (5) having a statistically large enough sample.
- ID:
- ivo://CDS.VizieR/J/A+A/618/A110
- Title:
- IR nebulae around bright massive stars
- Short Name:
- J/A+A/618/A110
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Recent studies show that more than 70% of massive stars do not evolve as effectively single stars, but as members of interacting binary systems. The evolution of these stars is thus strongly altered compared to similar but isolated objects. We investigate the occurrence of parsec-scale mid-infrared nebulae around early-type stars. If they exist over a wide range of stellar properties, one possible overarching explanation is non-conservative mass transfer in binary interactions, or stellar mergers. For ~3850 stars (all OBA stars in the Bright Star Catalogue (BSC, Cat. V/50), Be stars, BeXRBs, and Be+sdO systems), we visually inspect WISE 22um images. Based on nebular shape and relative position, we distinguish five categories: offset bow shocks structurally aligned with the stellar space velocity, unaligned offset bow shocks, and centered, unresolved, and not classified nebulae. In the BSC, we find that 28%, 13%, and 0.4% of all O, B, and A stars, respectively, possess associated infrared (IR) nebulae. Additionally, 34/234 Be stars, 4/72 BeXRBs, and 3/17 Be+sdO systems are associated with IR nebulae. Aligned or unaligned bow shocks result from high relative velocities between star and interstellar medium (ISM) that are dominated by the star or the ISM, respectively. About 13% of the centered nebulae could be bow shocks seen head- or tail-on. For the rest, the data disfavor explanations as remains of parental disks, supernova remnants of a previous companion, and dust production in stellar winds. The existence of centered nebulae also at high Galactic latitudes strongly limits the global risk of coincidental alignments with condensations in the ISM. Mass loss during binary evolution seems a viable mechanism for the formation of at least some of these nebulae. In total, about 29% of the IR nebulae (2% of all OBA stars in the BSC) may find their explanation in the context of binary evolution.
