Drawing from harmonized surveys of firms around the world, we compare employers' responses with actual labor legislation. Employers' concerns about labor regulations are closely related to the ...relative stringency of labor laws. Medium and large firms, as well as innovating firms, are those most negatively affected by onerous labor regulations.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
In this paper a direct method to estimate maximum power points (MPPs) in PV arrays subjected to mismatching conditions is presented. The method uses the lossless single-diode model (SDM) which is ...parameterized using the data of inflection and maximum power points of each panel. The reconstruction of power vs. voltage curve is obtained by one explicit equation, thus avoiding the use of recursive non-linear equations solver. The performance of this technique has been validated in terms of computation time and accuracy by means of the comparison with other existing methods.
The 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.
We 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 \(P=3.6127647\pm0.0000033\) days and a radius of ...\(1.586_{-0.040}^{+0.039}\) \(R_J\). We set an upper limit on the planetary mass of \(M_P<3.91\) \(M_J\) at \(3\sigma\) 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 \(\lambda=-5.6_{-1.9}^{+1.7 \circ}\). The star has \(T_{\mathrm{eff}}=7598_{-84}^{+81}\) K, \(M_*=1.458_{-0.028}^{+0.029}\) \(M_{\odot}\), \(R_*=1.638\pm0.034\) \(R_{\odot}\), and \(v\sin I_*=146\) km s\(^{-1}\), 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 \(\alpha\)-enhanced, with Fe/H\(=-0.405_{-0.033}^{+0.032}\) and \(\alpha\)/Fe\(=0.145 \pm 0.053\); 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 \(\Delta K_S=6.39 \pm 0.06\) 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 \(\sim0.12\) \(M_{\odot}\), a projected mutual separation of \(\sim20\) AU, and a projected separation of \(\sim500\) AU from KELT-21. KELT-21b may be one of only a handful of known transiting planets in hierarchical triple stellar systems.
We 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.
The amount of ultraviolet irradiation and ablation experienced by a planet depends strongly on the temperature of its host star. Of the thousands of extra-solar planets now known, only four giant ...planets have been found that transit hot, A-type stars (temperatures of 7300-10,000K), and none are known to transit even hotter B-type stars. WASP-33 is an A-type star with a temperature of ~7430K, which hosts the hottest known transiting planet; the planet is itself as hot as a red dwarf star of type M. The planet displays a large heat differential between its day-side and night-side, and is highly inflated, traits that have been linked to high insolation. However, even at the temperature of WASP-33b's day-side, its atmosphere likely resembles the molecule-dominated atmospheres of other planets, and at the level of ultraviolet irradiation it experiences, its atmosphere is unlikely to be significantly ablated over the lifetime of its star. Here we report observations of the bright star HD 195689, which reveal a close-in (orbital period ~1.48 days) transiting giant planet, KELT-9b. At ~10,170K, the host star is at the dividing line between stars of type A and B, and we measure the KELT-9b's day-side temperature to be ~4600K. This is as hot as stars of stellar type K4. The molecules in K stars are entirely dissociated, and thus the primary sources of opacity in the day-side atmosphere of KELT-9b are likely atomic metals. Furthermore, KELT-9b receives ~700 times more extreme ultraviolet radiation (wavelengths shorter than 91.2 nanometers) than WASP-33b, leading to a predicted range of mass-loss rates that could leave the planet largely stripped of its envelope during the main-sequence lifetime of the host star.
We 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 $T_{\rm eff} = 6278 \pm 51$ K, $\log{g_\star} =
3.89^{+0.054}_{-0.051}$, and Fe/H = $0.19^{+0.083}_{-0.085}$, with an
inferred mass $M_{\star} = 1.59^{+0.071}_{-0.091} M_\odot$ and radius $R_\star
= 2.37 \pm 0.18 R_\odot$. The planetary companion has $M_{\rm P} = 0.95 \pm
0.14 M_{\rm J}$, $R_{\rm P} = 1.79^{+0.18}_{-0.17} R_{\rm J}$, $\log{g_{\rm P}}
= 2.87^{+0.097}_{-0.098}$, and density $\rho_{\rm P} = 0.21^{+0.075}_{-0.054}$
g cm$^{-3}$, making it one of the most inflated giant planets known. The time
of inferior conjunction in ${\rm BJD_{TDB}}$ is $2457088.692055 \pm 0.0009$ and
the period is $P = 5.0316144 \pm 0.0000306$ days. Despite the relatively large
separation of $\sim0.07$ AU implied by its $\sim 5.03$-day orbital period,
KELT-12b receives significant flux of $2.93^{+0.33}_{-0.30} \times 10^9$ erg
s$^{-1}$ cm$^{-2}$ from its host. We compare the radii and insolations of
transiting gas-giant planets around hot ($T_{\rm eff} \geq 6250$ 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.
We 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 \(T_{\rm eff} = 6278 \pm 51\) K, \(\log{g_\star} = 3.89^{+0.054}_{-0.051}\), and Fe/H = \(0.19^{+0.083}_{-0.085}\), with an inferred mass \(M_{\star} = 1.59^{+0.071}_{-0.091} M_\odot\) and radius \(R_\star = 2.37 \pm 0.18 R_\odot\). The planetary companion has \(M_{\rm P} = 0.95 \pm 0.14 M_{\rm J}\), \(R_{\rm P} = 1.79^{+0.18}_{-0.17} R_{\rm J}\), \(\log{g_{\rm P}} = 2.87^{+0.097}_{-0.098}\), and density \(\rho_{\rm P} = 0.21^{+0.075}_{-0.054}\) g cm\(^{-3}\), making it one of the most inflated giant planets known. The time of inferior conjunction in \({\rm BJD_{TDB}}\) is \(2457088.692055 \pm 0.0009\) and the period is \(P = 5.0316144 \pm 0.0000306\) days. Despite the relatively large separation of \(\sim0.07\) AU implied by its \(\sim 5.03\)-day orbital period, KELT-12b receives significant flux of \(2.93^{+0.33}_{-0.30} \times 10^9\) erg s\(^{-1}\) cm\(^{-2}\) from its host. We compare the radii and insolations of transiting gas-giant planets around hot (\(T_{\rm eff} \geq 6250\) 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.
