We report the discovery of the transiting exoplanets WASP-95b, WASP-96b, WASP-97b, WASP-98b, WASP-99b, WASP-100b and WASP-101b. All are hot Jupiters with orbital periods in the range 2.1-5.7 d, ...masses of 0.5-2.8 ... and radii of 1.1-1.4 ... The orbits of all the planets are compatible with zero eccentricity. WASP-99b produces the shallowest transit yet found by WASP-South, at 0.4 per cent. The host stars are of spectral type F2-G8. Five have metallicities of Fe/H from -0.03 to +0.23, while WASP-98 has a metallicity of -0.60, exceptionally low for a star with a transiting exoplanet. Five of the host stars are brighter than V = 10.8, which significantly extends the number of bright transiting systems available for follow-up studies. WASP-95 shows a possible rotational modulation at a period of 20.7 d. We discuss the completeness of WASP survey techniques by comparing to the HATnet project. (ProQuest: ... denotes formulae/symbols omitted.)
Abstract
We present a new analysis of the rapidly oscillating Ap (roAp) star, 2MASS J19400781 − 4420093 (J1940; V = 13.1). The star was discovered using SuperWASP broad-band photometry to have a ...frequency of 176.39 d−1 (2041.55 μHz; P = 8.2 min; Holdsworth et al. 2014a) and is shown here to have a peak-to-peak amplitude of 34 mmag. J1940 has been observed during three seasons at the South African Astronomical Observatory, and has been the target of a Whole Earth Telescope campaign. The observations reveal that J1940 pulsates in a distorted quadrupole mode with unusual pulsational phase variations. A higher signal-to-noise ratio spectrum has been obtained since J1940's first announcement, which allows us to classify the star as A7 Vp Eu(Cr). The observing campaigns presented here reveal no pulsations other than the initially detected frequency. We model the pulsation in J1940 and conclude that the pulsation is distorted by a magnetic field of strength 1.5 kG. A difference in the times of rotational maximum light and pulsation maximum suggests a significant offset between the spots and pulsation axis, as can be seen in roAp stars.
We report on the discovery of a new extremely short period transiting extrasolar planet, WASP-19b. The planet has mass M pl = 1.15 +/- 0.08 MJ, radius R pl = 1.31 +/- 0.06 RJ, and orbital period P = ...0.7888399 +/- 0.0000008 days. Through spectroscopic analysis, we determine the host star to be a slightly super-solar metallicity (M/H = 0.1 +/- 0.1 dex) G-dwarf with T eff = 5500 +/- 100 K. In addition, we detect periodic, sinusoidal flux variations in the light curve which are used to derive a rotation period for the star of P rot = 10.5 +/- 0.2 days. The relatively short stellar rotation period suggests that either WASP-19 is somewhat young (~ 600 Myr old) or tidal interactions between the two bodies have caused the planet to spiral inward over its lifetime resulting in the spin-up of the star. Due to the detection of the rotation period, this system has the potential to place strong constraints on the stellar tidal quality factor, Q's, if a more precise age is determined.
ABSTRACT
Ground‐based spectroscopic follow‐up observations of the pulsating stars observed by the Kepler satellite mission are needed for their asteroseismic modelling. We aim to derive the ...fundamental parameters for a sample of 26 γ Doradus candidate stars observed by the Kepler satellite mission to accomplish one of the required pre‐conditions for their asteroseismic modelling and to compare our results with the types of pulsators expected from the existing light‐curve analysis. We use the spectrum synthesis method to derive the fundamental parameters like Teff, log g, M/H and v sin i from newly obtained spectra and compute the spectral energy distribution from literature photometry to get an independent measure of Teff. We find that most of the derived Teff values agree with the values given in the Kepler Input Catalog. According to their positions in the HR diagram, three stars are expected γ Dor stars, 10 stars are expected δ Sct stars and seven stars are possibly δ Sct stars at the hot border of the instability strip. Four stars in our sample are found to be spectroscopic binary candidates and four stars have very low metallicity where two show about solar C abundance. Six of the 10 stars located in the δ Sct instability region of the HR diagram show both δ Sct‐ and γ Dor‐type oscillations in their light curves, implying that γ Dor‐like oscillations are much more common among the δ Sct stars than predicted by theory. Moreover, seven stars showing periods in the δ Sct and the δ Sct‐γ Dor range in their light curves are located in the HR diagram left of the blue edge of the theoretical δ Sct instability strip. The consistency of these findings with recent investigations based on high‐quality Kepler data implies the need for a revision of the theoretical γ Dor and δ Sct instability strips.
Farm viability poses a grave challenge to the sustainability of agriculture and food systems: the number of acres in production continues to decline as the majority of farms earn negative net income. ...Two related and often overlapping marketing strategies, (i) locally grown foods and (ii) distribution at farmers markets, can directly enhance food system sustainability by improving farm profitability and long-term viability, as well as contributing to an array of ancillary benefits. We present results of a representative Michigan telephone survey, which measured consumers’ perceptions and behaviors around local foods and farmers markets. We discuss the implications of our findings on greater farm profitability. We conclude with suggestions for future research to enhance the contributions of locally grown foods and farmers markets to overall food system sustainability.
Abstract
We present 16 occultation and three transit light curves for the ultra-short period hot Jupiter WASP-103b, in addition to five new radial velocity measurements. We combine these observations ...with archival data and perform a global analysis of the resulting extensive data set, accounting for the contamination from a nearby star. We detect the thermal emission of the planet in both the z΄ and KS bands, the measured occultation depths being 699±110 ppm (6.4σ) and $3567_{-350}^{+400}$ ppm (10.2σ), respectively. We use these two measurements, together with recently published HST/WFC3 data, to derive joint constraints on the properties of WASP-103b's dayside atmosphere. On one hand, we find that the z΄ band and WFC3 data are best fit by an isothermal atmosphere at 2900 K or an atmosphere with a low H2O abundance. On the other hand, we find an unexpected excess in the KS band measured flux compared to these models, which requires confirmation with additional observations before any interpretation can be given. From our global data analysis, we also derive a broad-band optical transmission spectrum that shows a minimum around 700 nm and increasing values towards both shorter and longer wavelengths. This is in agreement with a previous study based on a large fraction of the archival transit light curves used in our analysis. The unusual profile of this transmission spectrum is poorly matched by theoretical spectra and is not confirmed by more recent observations at higher spectral resolution. Additional data, in both emission and transmission, are required to better constrain the atmospheric properties of WASP-103b.
We report the discovery of three extrasolar planets that transit their moderately bright (m
V= 12-13) host stars. WASP-44b is a 0.89-M
Jup planet in a 2.42-day orbit around a G8V star. WASP-45b is a ...1.03-M
Jup planet which passes in front of the limb of its K2V host star every 3.13 days. Weak Ca ii H&K emission seen in the spectra of WASP-45 suggests that the star is chromospherically active. WASP-46b is a 2.10-M
Jup planet in a 1.43-day orbit around a G6V star. Rotational modulation of the light curves of WASP-46 and weak Ca ii H&K emission in its spectra show the star to be photospherically and chromospherically active.
We imposed circular orbits in our analyses as the radial-velocity data are consistent with (near-)circular orbits, as could be expected from both empirical and tidal-theory perspectives for such short-period, ∼Jupiter-mass planets. We discuss the impact of fitting for eccentric orbits for such planets when not supported by the data. The derived planetary and stellar radii depend on the fitted eccentricity and these parameters inform intense theoretical efforts concerning tidal circularization and heating, bulk planetary composition and the observed systematic errors in planetary and stellar radii. As such, we recommend exercising caution in fitting the orbits of short-period, ∼Jupiter-mass planets with an eccentric model when there is no evidence of non-circularity.
We present new light curves of the massive hot Jupiter system WASP-18 obtained with the Spitzer spacecraft covering the entire orbit at 3.6 and 4.5 μm. These light curves are used to measure the ...amplitude, shape and phase of the thermal phase effect for WASP-18 b. We find that our results for the thermal phase effect are limited to an accuracy of about 0.01 per cent by systematic noise sources of unknown origin. At this level of accuracy we find that the thermal phase effect has a peak-to-peak amplitude approximately equal to the secondary eclipse depth, has a sinusoidal shape and that the maximum brightness occurs at the same phase as mid-occultation to within about 5 ° at 3.6 μm and to within about 10 ° at 4.5 μm. The shape and amplitude of the thermal phase curve imply very low levels of heat redistribution within the atmosphere of the planet. We also perform a separate analysis to determine the system geometry by fitting a light curve model to the data covering the occultation and the transit. The secondary eclipse depths we measure at 3.6 and 4.5 μm are in good agreement with previous measurements and imply a very low albedo for WASP-18 b. The parameters of the system (masses, radii, etc.) derived from our analysis are also in good agreement with those from previous studies, but with improved precision. We use new high-resolution imaging and published limits on the rate of change of the mean radial velocity to check for the presence of any faint companion stars that may affect our results. We find that there is unlikely to be any significant contribution to the flux at Spitzer wavelengths from a stellar companion to WASP-18. We find that there is no evidence for variations in the times of eclipse from a linear ephemeris greater than about 100 s over 3 years.
We report the discovery of a transiting planet with an orbital period of 3.05 days orbiting the star TYC 7247-587-1. The star, WASP-41, is a moderately bright G8
V
V
star (
V = 11.6
V
=
11.6
) with a ...metallicity close to solar (Fe/H = -0.08 ± 0.09
Fe
/
H
=
-
0.08
±
0.09
). The star shows evidence of moderate chromospheric activity, both from emission in the cores of the Ca iiH and K ines and photometric variability with a period of 18.4 days and an amplitude of about 1%. We use a new method to show quantitatively that this periodic signal has a low false-alarm probability. The rotation period of the star implies a gyrochronological age for WASP-41 of 1.8 Gyr with an error of about 15%. We have used a combined analysis of the available photometric and spectroscopic data to derive the mass and radius of the planet (0.92 ± 0.06 M
Jup
0.92
±
0.06
M
Jup
,1.20 ± 0.06 R
Jup
1.20
±
0.06
R
Jup
). Further observations of WASP-41 can be used to explore the connections between the properties of hot Jupiter planets and the level of chromospheric activity in their host stars.
We derive absolute dimensions of the early B-type detached eclipsing binary V453 Cygni (B0.4 IV + B0.7 IV, P= 3.89 d), a member of the open cluster NGC 6871. From the analysis of new, high-resolution ...spectroscopy and the UBV light curves of Cohen, we find the masses to be 14.36 ± 0.20 and 11.11 ± 0.13 M⊙, the radii to be 8.55 ± 0.06 and 5.49 ± 0.06 R⊙, and the effective temperatures to be 26 600 ± 500 and 25 500 ± 800 K for the primary and secondary stars, respectively. The surface gravity values of log g= 3.731 ± 0.012 and 4.005 ± 0.015 indicate that V453 Cyg is reaching the end of its main-sequence lifetime. We have determined the apsidal motion period of the system to be 66.4 ± 1.8 yr using the technique of Lacy extended to include spectroscopic data as well as times of minimum light, giving a density concentration coefficient of log k2=−2.226 ± 0.024. Contaminating (third) light has been detected for the first time in the light curve of V453 Cyg; previous analyses without this effect systematically underestimate the ratio of the radii of the two stars. The absolute dimensions of the system have been compared with the stellar evolution models of the Granada, Geneva, Padova and Cambridge groups. All model sets fit the data on V453 Cyg for solar helium and metal abundances and an age of 10.0 ± 0.2 Myr. The Granada models also agree fully with the observed log k2 once general relativistic effects have been accounted for. The Cambridge models with convective core overshooting fit V453 Cyg better than those without. Given this success of the theoretical predictions, we briefly discuss which eclipsing binaries should be studied in order to challenge the models further.
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