Olive fruit fly, Bactrocera oleae (Rossi) (Diptera: Tephritidae), is the major pest of commercial olives worldwide. Various aspects of its biology, ecology, management, and impact on olive production ...are highlighted. With the discovery of insecticidal resistance in some populations frequently treated with organophosphates, old and new control options are being investigated. The potential of biological control is examined. Surveys suggest that a small group of braconids in the Opiinae subfamily best represent the primary parasitoids attacking olive fruit fly in its native range. These species include Psyttalia lounsburyi, P. dacicida, P. concolor, P. ponerophaga, and Utetes africanus. Bracon celer, another braconid but in the Braconinae subfamily, is also reared from the fruit fly in its native range. The potential of these and other natural enemies is discussed with respect to olive fruit fly biology, commercial olive production, and biological constraints that may limit their success. We suggest that numerous species exist that should be further investigated as control agents for olive fruit fly in the many climatic regimes where the pest is found.
ABSTRACT Studying the properties of young planetary systems can shed light on how the dynamics and structure of planets evolve during their most formative years. Recent K2 observations of nearby ...young clusters (10-800 Myr) have facilitated the discovery of such planetary systems. Here we report the discovery of a Neptune-sized planet transiting an M4.5 dwarf (K2-25) in the Hyades cluster (650-800 Myr). The light curve shows a strong periodic signal at 1.88 days, which we attribute to spot coverage and rotation. We confirm that the planet host is a member of the Hyades by measuring the radial velocity of the system with the high-resolution near-infrared spectrograph Immersion Grating Infrared Spectrometer. This enables us to calculate a distance based on K2-25's kinematics and membership to the Hyades, which in turn provides a stellar radius and mass to 5%-10%, better than what is currently possible for most Kepler M dwarfs (12%-20%). We use the derived stellar density as a prior on fitting the K2 transit photometry, which provides weak constraints on eccentricity. Utilizing a combination of adaptive optics imaging and high-resolution spectra, we rule out the possibility that the signal is due to a bound or background eclipsing binary, confirming the transits' planetary origin. K2-25b has a radius ( R⊕) much larger than older Kepler planets with similar orbital periods (3.485 days) and host-star masses (0.29 M ). This suggests that close-in planets lose some of their atmospheres past the first few hundred million years. Additional transiting planets around the Hyades, Pleiades, and Praesepe clusters from K2 will help confirm whether this planet is atypical or representative of other close-in planets of similar age.
Abstract
WASP-33b is a retrograde hot Jupiter with a period of 1.2 d orbiting a rapidly rotating and pulsating A-type star. A previous study found that the transit chord of WASP-33b had changed ...slightly from 2008 to 2014 based on Doppler tomographic measurements. They attributed the change to orbital precession caused by the non-zero oblateness of the host star and the misaligned orbit. We aim to confirm and more precisely model the precession behavior using additional Doppler tomographic data of WASP-33b obtained with the High Dispersion Spectrograph on the 8.2 m Subaru telescope in 2011, as well as the data sets used in the previous study. Using equations of long-term orbital precession, we constrain the stellar gravitational quadrupole moment J2 = (9.14 ± 0.51) × 10−5 and the angle between the stellar spin axis and the line of sight $i_{\star }=96^{+10}_{-14}$ deg. These updated values show that the host star is more spherical and viewed more equator than the previous study. We also estimate that the precession period is ∼840 yr. We also find that the precession amplitude of WASP-33b is ∼67° and WASP-33b transits in front of the host star for only ∼20% of the whole precession period.
ABSTRACT We have analyzed new and archival time series spectra taken six years apart during transits of the hot Jupiter WASP-33 b, and spectroscopically resolved the line profile perturbation caused ...by the Rossiter-McLaughlin effect. The motion of this line profile perturbation is determined by the path of the planet across the stellar disk, which we show to have changed between the two epochs due to nodal precession of the planetary orbit. We measured rates of change of the impact parameter and the sky-projected spin-orbit misalignment of and , respectively, corresponding to a rate of nodal precession of . This is only the second measurement of nodal precession for a confirmed exoplanet transiting a single star. Finally, we used the rate of precession to set limits on the stellar gravitational quadrupole moment of
Abstract
Mass, radius, and age measurements of young (≲100 Myr) planets have the power to shape our understanding of planet formation. However, young stars tend to be extremely variable in both ...photometry and radial velocity (RV) measurements, which makes constraining these properties challenging. The V1298 Tau system of four ∼0.5
R
J
planets transiting a pre-main-sequence star presents an important, if stress-inducing, opportunity to observe and measure directly the properties of infant planets. Suárez Mascareño et al. published radial-velocity-derived masses for two of the V1298 Tau planets using a state-of-the-art Gaussian process regression framework. The planetary densities computed from these masses were surprisingly high, implying extremely rapid contraction after formation in tension with most existing planet-formation theories. In an effort to constrain further the masses of the V1298 Tau planets, we obtained 36 RVs using Keck/HIRES, and analyzed them in concert with published RVs and photometry. Through performing a suite of cross-validation tests, we found evidence that the preferred model of Suárez Mascareño et al. suffers from overfitting, defined as the inability to predict unseen data, rendering the masses unreliable. We detail several potential causes of this overfitting, many of which may be important for other RV analyses of other active stars, and recommend that additional time and resources be allocated to understanding and mitigating activity in active young stars such as V1298 Tau.
Abstract
Hot Jupiters orbiting rapidly rotating stars on inclined orbits undergo tidally induced nodal precession measurable over several years of observations. The Hot Jupiters WASP-33 b and KELT-9 ...b are particularly interesting targets because they are among the hottest planets found to date, orbiting relatively massive stars. Here, we analyze archival and new data that span 11 and 5 yr for WASP-33 b and KELT-9 b, respectively, in order to model and improve upon their tidal precession parameters. Our work confirms the nodal precession for WASP-33 b and presents the first clear detection of the precession of KELT-9 b. We determine that WASP-33 and KELT-9 have gravitational quadrupole moments
(
6.3
−
0.8
+
1.2
)
×
10
−
5
and
(
3.26
−
0.80
+
0.93
)
×
10
−
4
, respectively. We estimate the planets’ precession periods to be
1460
−
130
+
170
yr and
890
−
140
+
200
yr, respectively, and that they will cease to transit their host stars around the years
2090
−
10
+
17
CE and
2074
−
10
+
12
CE, respectively. Additionally, we investigate both planets’ tidal and orbital evolution, suggesting that a high-eccentricity tidal migration scenario is possible to produce both system architectures and that they will most likely not be engulfed by their hosts before the end of their main-sequence lifetimes.
Abstract
Young transiting exoplanets (<100 Myr) provide crucial insight into atmospheric evolution via photoevaporation. However, transmission spectroscopy measurements to determine atmospheric ...composition and mass loss are challenging due to the activity and prominent stellar disk inhomogeneities present on young stars. We observed a full transit of V1298 Tau c, a 23 Myr, 5.59
R
⊕
planet orbiting a young K0-K1.5 solar analog with GRACES on Gemini North. We were able to measure the Doppler tomographic signal of V1298 Tau c using the Ca
ii
infrared triplet (IRT) and find a projected obliquity of
λ
= 5° ± 15°. The tomographic signal is only seen in the chromospherically driven core of the Ca
ii
IRT, which may be the result of star-planet interactions. Additionally, we find that excess absorption of the H
α
line decreases smoothly during the transit. While this could be a tentative detection of hot gas escaping the planet, we find this variation is consistent with similar timescale observations of other young stars that lack transiting planets over similar timescales. We show this variation can also be explained by the presence of starspots with surrounding facular regions. More observations both in and out of the transits of V1298 Tau c are required to determine the nature of the Ca
ii
IRT and H
α
line variations.
Abstract
We present measurements of the spin–orbit misalignments of the hot Jupiters HAT-P-41 b and WASP-79 b, and the aligned warm Jupiter Kepler-448 b. We obtain these measurements with Doppler ...tomography, where we spectroscopically resolve the line profile perturbation during the transit due to the Rossiter–McLaughlin effect. We analyze time series spectra obtained during portions of five transits of HAT-P-41 b, and find a value of the spin–orbit misalignment of
. We reanalyze the radial velocity Rossiter–McLaughlin data on WASP-79 b obtained by Addison et al. using Doppler tomographic methodology. We measure
, consistent with but more precise than the value found by Addison et al. For Kepler-448 b we perform a joint fit to the
Kepler
light curve, Doppler tomographic data, and a radial velocity data set from Lillo-Box et al. We find an approximately aligned orbit (
), in agreement with the value found by Bourrier et al. Through analysis of the
Kepler
light curve we measure a stellar rotation period of
days, and use this to argue that the full three-dimensional spin–orbit misalignment is small,
.
KELT-9 b is an ultra-hot Jupiter transiting a rapidly rotating, oblate early-A-type star in a polar orbit. We model the effect of rapid stellar rotation on KELT-9 b's transit light curve using ...photometry from the Transiting Exoplanet Survey Satellite to constrain the planet's true spin-orbit angle and to explore how KELT-9 b may be influenced by stellar gravity darkening. We constrain the host star's equatorial radius to be 1.089 0.017 times as large as its polar radius and its local surface brightness to vary by ∼38% between its hot poles and cooler equator. We model the stellar oblateness and surface brightness gradient and find that it causes the transit light curve to lack the usual symmetry around the time of minimum light. We take advantage of the light-curve asymmetry to constrain KELT-9 b's true spin-orbit angle ( ), agreeing with Gaudi et al. that KELT-9 b is in a nearly polar orbit. We also apply a gravity-darkening correction to the spectral energy distribution model from Gaudi et al. and find that accounting for rapid rotation gives a better fit to available spectroscopy and yields a more reliable estimate for the star's polar effective temperature.
Abstract The number of public-sector biological control scientists and practitioners in the United States was determined by a survey conducted in 2019. A total of 344 personnel were identified in 49 ...states and Washington DC; 218 employed by universities, 86 by the federal government and 36 by state departments of agriculture. There were 10-34 personnel in eight states, 6-9 in 11, and 0-5 in 31, overall averaging less than 50% of their combined effort on biological control. Applications for biological control agents included about 30% for row crops and vegetables; 12% each for orchards, urban landscapes, outdoor ornamentals, and forests; and 22% for the remainder. The federal government provided an average of 42% of the funding for university, federal, and state biological control research and extension. The states contributed 29-35%, commodity groups supplied 19-24%, and the remaining funds were from private sources. Of 54 universities in the United States, 18 conducted in-person classroom education and training in biological control, with seven offering courses via distance. However, another 18 universities had discontinued their comprehensive courses. Biological control instruction was incorporated into courses and workshops on integrated pest management and sustainable agriculture at 50 universities. Correspondingly, during the past 24 years, biological control has gradually developed from primarily an independent discipline to increasingly being part of integrated pest management. Classical, augmentative and conservation biological control have nevertheless remained distinguishable high priority subdisciplines. Funding continues to be essential for advancing biological control, requiring societal understanding and acceptance. Advancement of biological control in the United States will require increased investment in personnel and their education and training, along with delivery of effective pest management technologies.
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