Pubblicazioni

 

 

1 – OCCULTAZIONI ED ECLISSI TRA I SATELLITI MEDICEI: I RISULTATI DELLA CAMPAGNA PHEMU09 IN ITALIA

Abstract
Results of photometry of mutual phenomena (occultations and eclipses) between Galilean satellites are presented.
The observations were performed in Italy during the international campaign PHEMU09.
From the light curves, minimum’s light instant and flux drop are derived. Relevant deviations (O-C) with respect to the expected central instants are present for many events. Taking into account the relative satellites’ longitudinal velocity, longitudinal discrepancies in km (and arcseconds) are also computed. However, additional corrections or analytical models of the light curves could be still necessary to extract reliable physical meaning in strict sense.
The discrepancies with respect to the expected flux drops during the occultations are apparently uncorrelated with
the O-C on timing (and longitudinal deviations in km); moreover, for eclipses they seem greater than for occultations.
The photometric light curves have been sent to the international collection centre, to be published on a professional refereed journal and modelled to improve the satellites’ motion parameters.

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2 – MINIMA OF ECLIPSING BINARIES AND NEW EPHEMERIDES FOR GSC 03881-00579 AND EZ LAC 

The list herebelow contains 163 times of minimum for 79 eclipsing binary stars (including the cataclysmic AM Her) calculated from CCD observations made by participants in the SSV-UAI Eclipsing Binaries Program. All the observatories are located in Italy; one is managed by the Physics Department of the University of Siena, while the others are privately operated. Some light curves were remotely obtained (via Internet) using the Italian and Australian telescopes of the Skylive-UAI Project, that are publicly available on the web site www.skylive.it.
The observations were reduced following standard procedures (see next section) and the light curves were analyzed using the Kwee−van Woerden algorithm (Kwee & van Woerden, 1956) to determine the times of minimum. All the times of minimum listed in this paper are heliocentric.
It is worth noting that most of the observed stars are neglected objects.

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3 – MULTI-SITE CAMPAIGN FOR TRANSIT TIMING VARIATIONS OF WASP-12b: POSSIBLE DETECTION OF A LONG-PERIOD SIGNAL OF PLANETARY ORIGIN

AbstractThe transiting planet WASP-12 b was identified as a potential target for transit timing studies because a departure from a linear ephemeris was reported in the literature. Such deviations could be caused by an additional planet in the system. We attempt to confirm the existence of claimed variations in transit timing and interpret its origin. We organised a multi-site campaign to observe transits by WASP-12 b in three observing seasons, using 0.5-2.6-metre telescopes. We obtained 61 transit light curves, many of them with sub-millimagnitude precision. The simultaneous analysis of the best-quality datasets allowed us to obtain refined system parameters, which agree with values reported in previous studies. The residuals versus a linear ephemeris reveal a possible periodic signal that may be approximated by a sinusoid with an amplitude of 0.00068+/-0.00013 d and period of 500+/-20 orbital periods of WASP-12 b. The joint analysis of timing data and published radial velocity measurements results in a two-planet model which better explains observations than single-planet scenarios. We hypothesize that WASP-12 b might be not the only planet in the system and there might be the additional 0.1 M_Jup body on a 3.6-d eccentric orbit. A dynamical analysis indicates that the proposed two-planet system is stable over long timescales.

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4 – SCOPERTA TRANSITO PIANETA HD 80606 

L’eclissi della stella HD 80606 da parte del proprio pianeta e’ stata scoperta nella notte tra il 13 e il 14 Febbraio da un
gruppo di astrofili italiani e in maniera indipendente da altri ricercatori in Spagna, Inghilterra e Francia.
La presenza di questo pianeta era già nota da altre misurazioni fisiche ma la scoperta del suo transito permette di
determinare con grande accuratezza il raggio del pianeta, cioè permette di ottenere un’importante informazione sulla
struttura interna di questo pianeta, utile anche per raffinare i modelli di formazione dei sistemi planetari.
Questo transito è il secondo scoperto dagli astrofili italiani appartenenti alla Sezione Pianeti Extrasolari dell’UAI
(Unione Astrofili Italiani), infatti già nel 2007 avevano scoperto il transito del pianeta HD 17156b. Il gruppo di
osservatori che ha effettuato la scoperta è composto da Giorgio Corfini,  Riccardo Papini, Fabio
Salvaggio, Toni Scarmato, Roberto Zambelli, e da Alessandro Marchini, Massimo Conti e Claudio Vallerani
dell’Osservatorio Astronomico dell’Università di Siena, coordinati dall’astronomo Mauro Barbieri. .
La grande quantità di calore ricevuta dalla stella durante questo breve tempo fa rapidamente riscaldare l’atmosfera del pianeta e ne innalza la temperatura di quasi 1000 gradi. Questa era la speculazione teorica di Gregory Laughlin che per verificarla, nel 2008 ha utilizzato il telescopio spaziale Spitzer per osservare nel lontano infrarosso la stella HD 80606 nei momenti prossimi al momento di maggior avvicinamento del pianeta alla stella. Ciò che effettivamente ha osservato Laughlin è stato si l’aumento della luminosità della stella, in realtà dovuta all’aumento della temperatura dell’atmosfera del pianeta, ma ha anche osservato un altro fenomeno ben più raro: ovvero ha osservato la stella che eclissava il pianeta.
Il pianeta era così caldo e luminoso che quando è passato prospetticamente dietro alla stella, la luminosità totale
misurata è diminuita confermando quindi le previsioni di Laughlin.
La presenza di questa eclissi del pianeta ha fatto ben sperare che il pianeta potesse anche passare di fronte al disco della propria stella occultandola in parte. Lo stesso Laughlin ha organizzato una campagna osservativa mondiale per cercare questo elusivo transito. Elusivo perché le stime della durata del transito indicavano una durata compresa tra un minimo di zero (caso in cui il pianeta sfiora il bordo della stella) ed un massimo di 17 ore. Un evento quindi che non sarebbe stato osservabile per intero da nessun luogo sulla Terra, senza tenere conto del possibile fattore di disturbo dovuto alle condizioni meteorologiche.

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5 – LA BINARIA A ECLISSE V997 CYGNI: CURVA DI LUCE E NUOVA EFFEMERIDE 

Abstract
The results of recent CCD photometry of the variable star V997 Cygni are presented. The light curve confirms the star is a W UMa-type eclipsing binary (EW). The period analysis confirms definitively the ∼0.458
days value without any period variation’s evidence. The observed times of minimum are analyzed in the OC diagram, including old minima found in literature. The linear best fit of the times of minimum leads to the following new ephemeris: TMin(HJD) = 2455460.5124 + 0g .4582260 × E.

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6 – KELT_6 – SCOPERTA DI UN PIANETA

We report the discovery of KELT-6b, a mildly-inflated Saturn-mass planet transiting a metal-poor host. The
initial transit signal was identified in KELT-North survey data, and the planetary nature of the occultor was
confirmed via a combination of follow-up photometry, high-resolution imaging, high-resolution spectroscopy,
and precision radial velocity measurements. The fiducial model from a global analysis including constraints
from isochrones indicates that the V = 10.38 host star (TYC-2532-556-1) is a mildly evolved, late-F star
with Teff = 6102 ± 44 K, logg∗ = 4.0704+0.0415 −0.070 and [Fe/H] = −0.281 ± 0.039, with an inferred mass M∗ =
1.085±0.043 M⊙ and radius R∗ = 1.580+0.16 −0.094 R⊙. The planetary companion has mass MP = 0.430+0.045
−0.046 MJup, radius RP = 1.193+0.130 −0.077 RJup, surface gravity loggP = 2.868+0.063 −0.081, and density ρP = 0.311+0.069 −0.076 g cm−3
The planet is on an orbit with semimajor axis a = 0.07939±0.0010AU and eccentricity e = 0.22+0.12
−0.10, which is roughly consistent with circular, and has ephemeris of Tc(BJDTDB) = 2456269.3399±0.0072 and P = 7.84570±0.00020 d.
Equally plausible fits that employ empirical constraints on the host star parameters rather than isochrones
yield a larger planet mass and radius by ∼ 4 − 7%. KELT-6b has surface gravity and incident flux similar to
HD 209458b, but orbits a host that is more metal poor than HD 209458b by ∼ 0.3 dex. Thus, the KELT-6
system is a metal-poor analog of HD 209458, and offers the unique opportunity to perform a comparative
measurement of two similar planets in similar environments around stars of very different metallicities. The
precision radial velocity data also reveal an acceleration indicative of a longer-period third body in the system,
although the companion is not detected in Keck adaptive optics images.

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KELT-6b: A Transiting Mildly-Inflated Saturn with a Metal-Poor Host, 222nd Meeting of the American Astronomical Society, Indianapolis, IN, June 1-6, 2013.
Collins, K. A., Siverd, R., Beatty, T. G., Eastman, J., Gaudi, B. S., Pepper, J., Stassun, K., Latham, D. W., Bieryla, A., Manner, M., Jensen, E. L., Kielkopf, J. F., Gregorio, J., Fulton, B. J., Buchhave, L. A., Penev, K., Crepp, J. R., Cargile, P., Mack, C. E., Oberst, T. E., Avril, R. L., Mellon, S., McLeod, K. K., Dhital, S., Stefanik, R. P., Calkins, M. L., Esquerdo, G., Berlind, P. L., Street, R., Zambelli, R., Mao, Q., Richert, A. J., Gould, A., Depoy, D. L., Marshall, J. L., Pogge, R. W., Trueblood, M., Trueblood. P.,

 

7 – Qatar_2 – Physical properties, starspot activity, orbital obliquity, and transmission spectrum of the Qatar-2 planetary system from multi-colour photometry

AbstractWe present seventeen high-precision light curves of five transits of the planet Qatar-2b, obtained from four defocussed 2m-class telescopes. Three of the transits were observed simultaneously in the SDSS griz passbands using the seven-beam GROND imager on the MPG/ESO 2.2-m telescope. A fourth was observed simultaneously in Gunn grz using the CAHA 2.2-m telescope with BUSCA, and in r using the Cassini 1.52-m telescope. Every light curve shows small anomalies due to the passage of the planetary shadow over a cool spot on the surface of the host star. We fit the light curves with the prism+gemc model to obtain the photometric parameters of the system and the position, size and contrast of each spot. We use these photometric parameters and published spectroscopic measurements to obtain the physical properties of the system to high precision, finding a larger radius and lower density for both star and planet than previously thought. By tracking the change in position of one starspot between two transit observations we measure the orbital obliquity of Qatar-2 b to be 4.3 \pm 4.5 degree, strongly indicating an alignment of the stellar spin with the orbit of the planet. We calculate the rotation period and velocity of the cool host star to be 11.4 \pm 0.5 d and 3.28 \pm 0.13 km/s at a colatitude of 74 degree. We assemble the planet’s transmission spectrum over the 386-976 nm wavelength range and search for variations of the measured radius of Qatar-2 b as a function of wavelength. Our analysis highlights a possible H2/He Rayleigh scattering in the blue. Clicca qui per vedere l’articolo completo.

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8 – HIP 10680 – HIP 10679 – A VISUAL BINARY IN THE PICTORIS ASSOCIATION WITH THE FASTED ROTATING MEMBER

AbstractWe present the results of a multi-filter photometric monitoring of the wide binary HIP10680/HIP10679. We found both component to be variable with amplitude up to ΔV = 0.03 mag in the case of HIP10680 and ΔV = 0.07 mag in the case of HIP10679. We could measure the rotation periods P = 0.2396d of the hotter F5V component HIP10680 and P = 0.777d of the cooler G5V component HIP10679. We found that the rotation axes of both components are aligned with an inclination i =  10. Although the two components have a mass difference not larger than 15%, they exhibit a significant difference between their rotation periods. Such difference may arise either from different initial rotation periods or to different disc life times. For instance, the slower rotating component HIP 10679 hosts a well know debris disc.

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9 – KELT -8b: A HIGHLY INFLATED TRANSITING HOT JUPITER AND A NEW TECHNIQUE FOR EXTRACTING HIGH-PRECISION RADIAL VELOCITIES FROM NOISY SPECTRA

AbstractWe announce the discovery of a highly inflated transiting hot Jupiter discovered by the KELT-North survey. A global analysis including constraints from isochrones indicates that the V = 10.8 host star (HD 343246) is a mildly evolved, G dwarf with Teff=5754+5455 K, logg=4.078+0.0490.054[Fe/H]=0.272±0.038, an inferred mass M=1.211+0.0780.066 M, and radius R=1.67+0.140.12 R. The planetary companion has mass MP=0.867+0.0650.061 MJ, radius RP=1.86+0.180.16 RJ, surface gravity loggP=2.793+0.0720.075, and density ρP=0.167+0.0470.038 g cm3. The planet is on a roughly circular orbit with semimajor axis a=0.04571+0.000960.00084 AU and eccentricity e=0.035+0.0500.025. The best-fit linear ephemeris is T0=2456883.4803±0.0007 BJDTDB and P=3.24406±0.00016 days. This planet is one of the most inflated of all known transiting exoplanets, making it one of the few members of a class of extremely low density, highly-irradiated gas giants. The low stellar logg and large implied radius are supported by stellar density constraints from follow-up light curves, plus an evolutionary and space motion analysis. We also develop a new technique to extract high precision radial velocities from noisy spectra that reduces the observing time needed to confirm transiting planet candidates. This planet boasts deep transits of a bright star, a large inferred atmospheric scale height, and a high equilibrium temperature of Teq=1675+6155 K, assuming zero albedo and perfect heat redistribution, making it one of the best targets for future atmospheric characterization studies.

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10 – KELT -4b: AN INFLATED HOT JUPITER TRANSITING THE BRIGHT (V – 10) COMPONENT OF HIERARCHICAL TRIPLE 

AbstractWe report the discovery of KELT-4Ab, an inflated, transiting Hot Jupiter orbiting the brightest component of a hierarchical triple stellar system. The host star is an F star with Teff=6206±75 K, logg=4.108±0.014[Fe/H]=0.116+0.0650.069M=1.201+0.0670.061 M, and R=1.610+0.0780.068 R. The best-fit linear ephemeris is BJDTDB=2456193.29157±0.00021+E(2.9895936±0.0000048). With a magnitude of V10, a planetary radius of 1.699+0.0460.045 RJ, and a mass of 0.902+0.0600.059 MJ, it is the brightest host among the population of inflated Hot Jupiters (RP>1.5RJ), making it a valuable discovery for probing the nature of inflated planets. In addition, its existence within a hierarchical triple and its proximity to Earth (210 pc) provides a unique opportunity for dynamical studies with continued monitoring with high resolution imaging and precision radial velocities. In particular, the motion of the binary stars around each other and of both stars around the primary star relative to the measured epoch in this work should be detectable when it rises in October 2015.

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11- KELT -12b: A P^ 5 DAY, HIGHLY INFLATED HOT JUPITER TRANSITING a MILDLY EVOLVED HOT STAR

AbstractWe report the discovery of KELT-12b, a highly inflated Jupiter-mass planet transiting a mildly evolved host star. We identified the initial transit signal in the KELT-North survey data and established the planetary nature of the companion through precise follow-up photometry, high-resolution spectroscopy, precise radial velocity measurements, and high-resolution adaptive optics imaging. Our preferred best-fit model indicates that the V=10.64 host, TYC 2619-1057-1, has Teff=6278±51 K, logg=3.89+0.0540.051, and [Fe/H] = 0.19+0.0830.085, with an inferred mass M=1.59+0.0710.091M and radius R=2.37±0.18R. The planetary companion has MP=0.95±0.14MJRP=1.79+0.180.17RJloggP=2.87+0.0970.098, and density ρP=0.21+0.0750.054 g cm3, making it one of the most inflated giant planets known. The time of inferior conjunction in BJDTDB is 2457088.692055±0.0009 and the period is P=5.0316144±0.0000306 days. Despite the relatively large separation of 0.07 AU implied by its 5.03-day orbital period, KELT-12b receives significant flux of 2.93+0.330.30×109 erg s1 cm2 from its host. We compare the radii and insolations of transiting gas-giant planets around hot (Teff6250 K) and cool stars, noting that the observed paucity of known transiting giants around hot stars with low insolation is likely due to selection effects. We underscore the significance of long-term ground-based monitoring of hot stars and space-based targeting of hot stars with the Transiting Exoplanet Survey Satellite (TESS) to search for inflated giants in longer-period orbits.

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12 – KELT -16b: A HIGHLY IRRADIATED, ULTRA SHORT PERIOD HOT JUPITER NEARING TIDEL DISRUPTION

AbstractWe announce the discovery of KELT-16b, a highly irradiated, ultra-short period hot Jupiter transiting the relatively bright (V=11.7) star TYC 2688-1839-1. A global analysis of the system shows KELT-16 to be an F7V star with Teff=6236±54 K, logg=4.253+0.0310.036, [Fe/H] = -0.002+0.0860.085M=1.211+0.0430.046M, and R=1.360+0.0640.053R. The planet is a relatively high mass inflated gas giant with MP=2.75+0.160.15MJRP=1.415+0.0840.067RJ, density ρP=1.20±0.18 g cm3, surface gravity loggP=3.530+0.0420.049, and Teq=2453+5547 K. The best-fitting linear ephemeris is TC=2457247.24791±0.00019 BJDtdb and P=0.9689951±0.0000024 d. KELT-16b joins WASP-18b, -19b, -43b, -103b, and HATS-18b as the only giant transiting planets with P<1 day. Its ultra-short period and high irradiation make it a benchmark target for atmospheric studies by HST, Spitzer, and eventually JWST. For example, as a hotter, higher mass analog of WASP-43b, KELT-16b may feature an atmospheric temperature-pressure inversion and day-to-night temperature swing extreme enough for TiO to rain out at the terminator. KELT-16b could also join WASP-43b in extending tests of the observed mass-metallicity relation of the Solar System gas giants to higher masses. KELT-16b currently orbits at a mere  1.7 Roche radii from its host star, and could be tidally disrupted in as little as a few ×105 years (for a stellar tidal quality factor of Q=105). Finally, the likely existence of a widely separated bound stellar companion in the KELT-16 system makes it possible that Kozai-Lidov oscillations played a role in driving KELT-16b inward to its current precarious orbit.

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13 – KELT -17b: A HOT JUPITER TRANSITING AN A-STAR IN A MISALIGNED ORBIT DETECTED WITH DOPPLER TOMOGRAPHY

AbstractWe present the discovery of a hot-Jupiter transiting the V=9.23 mag main-sequence A-star KELT-17 (BD+14 1881). KELT-17b is a 1.31 -0.29/+0.28 Mj, 1.525 -0.060/+0.065 Rj hot-Jupiter in a 3.08 day period orbit misaligned at -115.9 +/- 4.1 deg to the rotation axis of the star. The planet is confirmed via both the detection of the radial velocity orbit, and the Doppler tomographic detection of the shadow of the planet over two transits. The nature of the spin-orbit misaligned transit geometry allows us to place a constraint on the level of differential rotation in the host star; we find that KELT-17 is consistent with both rigid-body rotation and solar differential rotation rates (alpha < 0.30 at 2 sigma significance). KELT-17 is only the fourth A-star with a confirmed transiting planet, and with a mass of 1.635 -0.061/+0.066 Msun, effective temperature of 7454 +/- 49 K, and projected rotational velocity v sin I_* = 44.2 -1.3/+1.5 km/s; it is amongst the most massive, hottest, and most rapidly rotating of known planet hosts. 

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14 – KELT – 18b: Puffy Planet, Hot Host, Probably Perturbed.

AbstractWe report the discovery of KELT-18b, a transiting hot Jupiter in a 2.87d orbit around the bright (V=10.1), hot, F4V star BD+60 1538 (TYC 3865-1173-1). We present follow-up photometry, spectroscopy, and adaptive optics imaging that allow a detailed characterization of the system. Our preferred model fits yield a host stellar temperature of 6670+/-120 K and a mass of 1.524+/-0.069 Msun, situating it as one of only a handful of known transiting planets with hosts that are as hot, massive, and bright. The planet has a mass of 1.18+/-0.11 Mjup, a radius of 1.57+/-0.04 Rjup, and a density of 0.377+/-0.040 g/cm^3, making it one of the most inflated planets known around a hot star. We argue that KELT-18b’s high temperature and low surface gravity, which yield an estimated ~600 km atmospheric scale height, combined with its hot, bright host make it an excellent candidate for observations aimed at atmospheric characterization. We also present evidence for a bound stellar companion at a projected separation of ~1100 AU, and speculate that it may have contributed to the strong misalignment we suspect between KELT-18’s spin axis and its planet’s orbital axis. The inferior conjunction time is 2457542.524998 +/-0.000416 (BJD_TDB) and the orbital period is 2.8717510 +/- 0.0000029 days. We encourage Rossiter-McLaughlin measurements in the near future to confirm the suspected spin-orbit misalignment of this system.

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15 – KELT – 9b: La scoperta è stata presentata durante il convegno annuale dell’Associazione Astronomica Americana (Aas) e pubblicata su Nature. La notizia è stata pubblicata ai primi di giugno di quest’anno anche sui maggiori quotidiani nazionali ed internazionali (Ansa, Focus, Repubblica, Corriere, Le Scienze, Istituto Nazionale di Astrofisica, Rainews, La Stampa).

Qui di seguito alcuni link con le notizie della scoperta:

http://www.media.inaf.it/2017/06/05/kelt-9b-il-pianeta-bollente/

http://www.rainews.it/dl/rainews/media/Il-Pianeta-rovente-Kelt9b-pallone-gonfiato-che-brucia-quasi-come-il-Sole-a13d3f25-7b70-42a1-a661-db2af94fb1de.html#foto-1

http://www.lastampa.it/2017/06/06/scienza/scoperto-un-nuovo-pianeta-bollente-keltb-pi-caldo-delle-stelle-con-i-suoi-gradi-q3o6PPIjjrPzmx4zVxoH3H/pagina.html

A 650 anni luce da noi, Kelt-9b è il pianeta più caldo mai visto finora. La sua temperatura supera i 4300 gradi, e la sua massa è pari a circa tre volte Giove. Il nuovo pianeta appartiene quindi alla famiglia dei “Giovi caldi” . (Credits: NASA/JPL-Caltech)

 

16 – KELT-20b: A giant planet with a period of P~ 3.5 days transiting the V~ 7.6 early A star HD 185603

AbstractWe report the discovery of KELT-20b, a hot Jupiter transiting a V~7.6 early A star with an orbital period of P~3.47 days. We identified the initial transit signal in KELT-North survey data. Archival and follow-up photometry, the Gaia parallax, radial velocities, Doppler tomography, and adaptive optics imaging were used to confirm the planetary nature of the companion and characterize the system. From global modeling we infer that the host star HD 185603 is a rapidly-rotating (VsinI~120 km/s) A2V star with an effective temperature of Teff=8730K, mass of Mstar=1.76Msun, radius of Rstar=1.561Rsun, surface gravity of logg=4.292, and age of <600 Myr. The planetary companion has a radius of 1.735+0.0700.075 RJ, a semimajor axis of a=0.0542+0.00140.0021AU, and a linear ephemeris of BJDTDB=2457503.120049±0.000190+E(3.4741070±0.0000019). We place a 3σ upper limit of ~3.5 MJ on the mass of the planet. The Doppler tomographic measurement indicates that the planetary orbit is well aligned with the projected spin-axis of the star (λ=3.4±2.1 degrees). The inclination of the star is constrained to be 24.4<I<155.6 degrees, implying a true (three-dimensional) spin-orbit alignment of 1.3<ψ<69.8 degrees. The planet receives an insolation flux of 8×109 erg s1 cm2, implying an equilibrium temperature of of ~ 2250 K, assuming zero albedo and complete heat redistribution. Due to the high stellar Teff, the planet also receives an ultraviolet (wavelengths d91.2~nm) insolation flux of 9.1×104 erg s1 cm2, which may lead to significant ablation of the planetary atmosphere. Together with WASP-33, Kepler-13 A, HAT-P-57, KELT-17, and KELT-9, KELT-20 is the sixth A star host of a transiting giant planet, and the third-brightest host (in V) of a transiting planet. Clicca qui per vedere tutto l’articolo. (clicca qui)

17 – KELT-19Ab: A P~4.6 Day Hot Jupiter Transiting a Likely Am Star with a Distant Stellar Companion –

AbstractWe present the discovery of the giant planet KELT-19Ab, which transits the moderately bright (V9.9) A8V star TYC 764-1494-1 with an orbital period of 4.61 days. We confirm the planetary nature of the companion via a combination of radial velocities, which limit the mass to <4.1MJ (3σ), and a clear Doppler tomography signal, which indicates a retrograde projected spin-orbit misalignment of λ=179.7+3.73.8 degrees. Global modeling indicates that the Teff=7500±110K host star has M=1.62+0.250.20M and R=1.83±0.10R. The planet has a radius of RP=1.91±0.11RJ and receives a stellar insolation flux of 3.2×109ergs1cm2, leading to an inferred equilibrium temperature of TEQ=∼1935K assuming zero albedo and complete heat redistribution. With a vsinI=84.8±2.0kms1, the host is relatively slowly rotating compared to other stars with similar effective temperatures, and it appears to be enhanced in metallic elements but deficient in calcium, suggesting that it is likely an Am star. KELT-19A would be the first detection of an Am host of a transiting planet of which we are aware. Adaptive optics observations of the system reveal the existence of a companion with late G9V/early K1V spectral type at a projected separation of 160AU. Radial velocity measurements indicate that this companion is bound. Most Am stars are known to have stellar companions, which are often invoked to explain the relatively slow rotation of the primary. In this case, the stellar companion is unlikely to have caused the tidal braking of the primary. However, it may have emplaced the transiting planetary companion via the Kozai-Lidov mechanism.

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18 – KELT -21b: Astronomers discover a ‘hot Jupiter’ orbiting a rapidly rotating star –

AbstractWe present the discovery of KELT-21b, a hot Jupiter transiting the V=10.5 A8V star HD 332124. The planet has an orbital period of P=3.6127647±0.0000033 days and a radius of 1.586+0.0390.040 RJ. We set an upper limit on the planetary mass of MP<3.91 MJ at 3σ confidence. We confirmed the planetary nature of the transiting companion using this mass limit and Doppler tomographic observations to verify that the companion transits HD 332124. These data also demonstrate that the planetary orbit is well-aligned with the stellar spin, with a sky-projected spin-orbit misalignment of λ=5.6+1.71.9. The star has Teff=7598+8184 K, M=1.458+0.0290.028 MR=1.638±0.034 R, and vsinI=146 km s1, the highest projected rotation velocity of any star known to host a transiting hot Jupiter. The star also appears to be somewhat metal-poor and α-enhanced, with [Fe/H]=0.405+0.0320.033 and [α/Fe]=0.145±0.053; these abundances are unusual, but not extraordinary, for a young star with thin-disk kinematics like KELT-21. High-resolution imaging observations revealed the presence of a pair of stellar companions to KELT-21, located at a separation of 1.2″ and with a combined contrast of ΔKS=6.39±0.06 with respect to the primary. Although these companions are most likely physically associated with KELT-21, we cannot confirm this with our current data. If associated, the candidate companions KELT-21 B and C would each have masses of 0.12 M, a projected mutual separation of 20 AU, and a projected separation of 500 AU from KELT-21. KELT-21b may be one of only a handful of known transiting planets in hierarchical triple stellar systems.

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19 – The KELT Follow-Up Network and Transit False Positive Catalog: Pre-vetted False Positives for TESS –

AbstractThe Kilodegree Extremely Little Telescope (KELT) project has been conducting a photometric survey for transiting planets orbiting bright stars for over ten years. The KELT images have a pixel scale of ~23″/pixel—very similar to that of NASA’s Transiting Exoplanet Survey Satellite (TESS)—as well as a large point spread function, and the KELT reduction pipeline uses a weighted photometric aperture with radius 3′. At this angular scale, multiple stars are typically blended in the photometric apertures. In order to identify false positives and confirm transiting exoplanets, we have assembled a follow-up network (KELT-FUN) to conduct imaging with higher spatial resolution, cadence, and photometric precision than the KELT telescopes, as well as spectroscopic observations of the candidate host stars. The KELT-FUN team has followed-up over 1,600 planet candidates since 2011, resulting in more than 20 planet discoveries. Excluding ~450 false alarms of non-astrophysical origin (i.e., instrumental noise or systematics), we present an all-sky catalog of the 1,128 bright stars (6<V<10) that show transit-like features in the KELT light curves, but which were subsequently determined to be astrophysical false positives (FPs) after photometric and/or spectroscopic follow-up observations. The KELT-FUN team continues to pursue KELT and other planet candidates and will eventually follow up certain classes of TESS candidates. The KELT FP catalog will help minimize the duplication of follow-up observations by current and future transit surveys such as TESS.

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20 – KELT 22Ab – A Massive Hot Jupiter Transiting a Near Solar Twin

AbstractWe present the discovery of KELT-22Ab, a hot Jupiter from the KELT-South survey. KELT-22Ab transits the moderately bright (V11.1) Sun-like G2V star TYC 7518-468-1. The planet has an orbital period of P=1.3866529±0.0000027 days, a radius of RP=1.285+0.120.071 RJ, and a relatively large mass of MP=3.47+0.150.14 MJ. The star has R=1.099+0.0790.046 RM=1.092+0.0450.041 MTeff=5767+5049  K, logg=4.393+0.0390.060  (cgs), and [m/H] = +0.259+0.0850.083 , and thus, other than its slightly super-solar metallicity, appears to be a near solar twin. Surprisingly, KELT-22A exhibits kinematics and a Galactic orbit that are somewhat atypical for thin disk stars. Nevertheless, the star is rotating quite rapidly for its estimated age, shows evidence of chromospheric activity, and is somewhat metal rich. Imaging reveals a slightly fainter companion to KELT-22A that is likely bound, with a projected separation of 6\arcsec (1400 AU). In addition to the orbital motion caused by the transiting planet, we detect a possible linear trend in the radial velocity of KELT-22A suggesting the presence of another relatively nearby body that is perhaps non-stellar. KELT-22Ab is highly irradiated (as a consequence of the small semi-major axis of a/R=4.97), and is mildly inflated. At such small separations, tidal forces become significant. The configuration of this system is optimal for measuring the rate of tidal dissipation within the host star. Our models predict that, due to tidal forces, the semi-major axis of KELT-22Ab is decreasing rapidly, and is thus predicted to spiral into the star within the next Gy.

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21 – KELT 23Ab – A hot Jupiter Transiting Near – Solar Twin Close to the TESS and JWST Continous Viewing Zones – 

AbstractWe announce the discovery of KELT-23Ab, a hot Jupiter transiting the relatively bright (V=10.3) star BD+66 911 (TYC 4187-996-1), and characterize the system using follow-up photometry and spectroscopy. A global fit to the system yields host-star properties of Teff=5900±49KM=0.945+0.0600.054MR=0.995±0.015RL=1.082+0.0510.048L, logg=4.418+0.0260.025 (cgs), and [Fe/H]=0.105±0.077. KELT-23Ab is a hot Jupiter with mass MP=0.938+0.0450.042MJ, radius RP=1.322±0.025RJ, and density ρP=0.504+0.0380.035 g cm3. Intense insolation flux from the star has likely caused KELT-23Ab to become inflated. The time of inferior conjunction is T0=2458149.40776±0.00091 BJDTDB and the orbital period is P=2.255353+0.0000310.000030 days. There is strong evidence that KELT-23A is a member of a long-period binary star system with a less luminous companion, and due to tidal interactions, the planet is likely to spiral into its host within roughly a Gyr. This system has one of the highest positive ecliptic latitudes of all transiting planet hosts known to date, placing it near the Transiting Planet Survey Satellite and James Webb Space Telescope continuous viewing zones. Thus we expect it to be an excellent candidate for long-term monitoring and follow-up with these facilities.

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22 – KELT 24b – A 5Mj Planet on a 5.6 day Well Aligned Orbit around the Young V 8.3 F Star HD 93148 – 

AbstractWe present the discovery of KELT-24 b, a massive hot Jupiter orbiting a bright (V=8.3 mag, K=7.2 mag) young F-star with a period of 5.6 days. The host star, KELT-24 (HD 93148), has a Teff =6509+5049 K, a mass of M = 1.460+0.0550.059 M, radius of R = 1.506±0.022 R, and an age of 0.78+0.610.42 Gyr. Its planetary companion (KELT-24 b) has a radius of RP = 1.272±0.021 RJ, a mass of MP = 5.18+0.210.22 MJ, and from Doppler tomographic observations, we find that the planet’s orbit is well-aligned to its host star’s projected spin axis (λ = 2.6+5.13.6). The young age estimated for KELT-24 suggests that it only recently started to evolve from the zero-age main sequence. KELT-24 is the brightest star known to host a transiting giant planet with a period between 5 and 10 days. Although the circularization timescale is much longer than the age of the system, we do not detect a large eccentricity or significant misalignment that is expected from dynamical migration. The brightness of its host star and its moderate surface gravity make KELT-24b an intriguing target for detailed atmospheric characterization through spectroscopic emission measurements since it would bridge the current literature results that have primarily focused on lower mass hot Jupiters and a few brown dwarfs.

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23 – KELT-25b and KELT-26b: A Hot Jupiter and a Substellar Companion Transiting Young A-stars Observed by TESS – 

We present the discoveries of KELT-25b (TIC 65412605, TOI-626.01) and KELT-26b (TIC 160708862, TOI-1337.01), two transiting companions orbiting relatively bright, early A-stars. The transit signals were initially detected by the KELT survey, and subsequently confirmed by \textit{TESS} photometry. KELT-25b is on a 4.40-day orbit around the V = 9.66 star CD-24 5016 (Teff=8280+440180 K, M = 2.18+0.120.11 M), while KELT-26b is on a 3.34-day orbit around the V = 9.95 star HD 134004 (Teff =8640+500240 K, M = 1.93+0.140.16 M), which is likely an Am star. We have confirmed the sub-stellar nature of both companions through detailed characterization of each system using ground-based and \textit{TESS} photometry, radial velocity measurements, Doppler Tomography, and high-resolution imaging. For KELT-25, we determine a companion radius of RP = 1.64+0.0390.043 RJ, and a 3-sigma upper limit on the companion’s mass of 64 MJ. For KELT-26b, we infer a planetary mass and radius of MP = 1.41+0.430.51 MJ and RP = 1.940+0.0600.058 RJ. From Doppler Tomographic observations, we find KELT-26b to reside in a highly misaligned orbit. This conclusion is weakly corroborated by a subtle asymmetry in the transit light curve from the \textit{TESS} data. KELT-25b appears to be in a well-aligned, prograde orbit, and the system is likely a member of a cluster or moving group.

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24 – MINIMA OF ECLIPSING BINARIES, VARIABILITY OF V840 HER ANDNSV5740, NEW EPHEMERIDES FOR V997 CYG, V1037, V1098, V1100 HER

Sezione Stelle Variabili – Unione Astrofili Italiani (UAI), e-mail:
 stellevariabili@uai.it
The accompanying list contains 97 times of minima for 49 eclipsing binary stars (in-cluding the cataclysmic DO Leo) calculated from CCD observations made by participantsin the SSV-UAI Eclipsing Binaries Program. All the observatories are located in Italy;one is managed by the Physics Department of the University of Siena, while the othersare privately operated.The observations were reduced following standard procedures (see next section) and thelight curves were analyzed using the Kwee
van Woerden algorithm (Kwee & van Woer-den, 1956) to determine the times of minimum. All the times of minimum listed in thispaper are heliocentric.We note most of the observed stars are neglected objects.
The times of minima, expressed as heliocentric Julian days (see the attached Table),were computed adopting the KW method (Kwee & van Woerden, 1956) using AVE(Barber´a, 1996). This algorithm also provides an error estimate, that is the formalinternal error of the KW method, so which can be considered as a lower limit of the actual uncertainty on times of minimum. Together with that error, we providean alternative estimate error according to the Arlot’s (modified) method (Arlot et al, 2009) by adopting the formulawhere m is the error inmagnitude and ∆  is the magnitude drop during a time range ∆ delimiting thepart of the light curve where the speed of decrease in magnitude is the highest. The factor takes into account that 2 branches (descending and ascending) contributeto the time of minimum estimation.The types of minimum quoted in the Table were deduced according the ephemeridesprovided by Kreiner’s (2004) web site (
http://www.as.up.krakow.pl/ephem
), byB.R.N.O. –
C Gatewa
 web site (
http://var.astro.cz/ocgate
) or by ourupdated elements (see below). Only in the latter case we are sure that the primaryminimum (conventionally at zero phase) is the deeper.
COMMISSIONS 27 AND 42 OF THE IAU
INFORMATION BULLETIN ON VARIABLE STARS
Number 5997
Konkoly Observatory
Budapest
6 September 2011
HU ISSN 0374 – 0676
MINIMA OF ECLIPSING BINARIES, VARIABILITY OF V840 HER AND
NSV5740, NEW EPHEMERIDES FOR V997 CYG, V1037, V1098, V1100 HER
ARENA, C.1,2; ACETI, P.3; BANFI, M.1; BELLIA, I.4; BIANCIARDI, G.4; CORFINI, G.1; MARCHINI,
A.1,5; MARINO, G.1,2; MARTINENGO, M.1; PAPINI, R.1; PESENTI, L.3; ROMEO, G.2;
RUOCCO, N.1,6; VINCENZI, M.1; ZAMBELLI, R.1
1 Sezione Stelle Variabili – Unione Astrofili Italiani (UAI), e-mail: stellevariabili@uai.it
2 Gruppo Astrofili Catanesi – via Milo, 28 I-95125 Catania, ITALY
3 Liceo Scientifico Iris Versari, Cesano Maderno (MI), ITALY
4 Skylive/Telescopio remoto UAI – ITALY
5 University of Siena Astronomical Observatory – Via Roma, 56 I-53100 Siena, ITALY
6 Astrocampania, Sez. Stabia – Penisola Sorrentina – ITALY

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