The Experts below are selected from a list of 360 Experts worldwide ranked by ideXlab platform
Yi-hong Xiu - One of the best experts on this subject based on the ideXlab platform.
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throttling process of the kerr newman anti de sitter black holes in the extended phase space
Physical Review D, 2018Co-Authors: Ze-wei Zhao, Yi-hong XiuAbstract:The throttling process of the Kerr--Newman--anti-de Sitter (KN--AdS) black holes is systematically studied in the extended phase space. In this framework, the cosmological constant is interpreted as a varying thermodynamic pressure, and the black hole mass is identified with enthalpy. The throttling process is essentially an adiabatic and isenthalpic (i.e., constant-mass) process for the KN--AdS black holes. The Joule--Thomson coefficient, Inversion Temperature, Inversion curve, and isenthalpic curve are investigated in order, with both analytical and numerical methods. It is found that there are no maximum Inversion Temperatures, but only minimum ones that are around one half of the critical Temperatures of the KN--AdS black holes. Two characteristic masses are also discussed to show the detailed features in the throttling behaviors of the KN--AdS black holes.
Adam Burrows - One of the best experts on this subject based on the ideXlab platform.
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the broadband infrared emission spectrum of the exoplanet tres 3
The Astrophysical Journal, 2010Co-Authors: Francois Fressin, Adam Burrows, David Charbonneau, Heather A Knutson, Francis T Odonovan, Georgi Mandushev, Drake Deming, David S SpiegelAbstract:We use the Spitzer Space Telescope to estimate the dayside thermal emission of the exoplanet TrES-3 integrated in the 3.6, 4.5, 5.8, and 8.0 μm bandpasses of the Infrared Array Camera (IRAC) instrument. We observe two secondary eclipses and find relative eclipse depths of 0.00346 ± 0.00035, 0.00372 ± 0.00054, 0.00449 ± 0.00097, and 0.00475 ± 0.00046, respectively, in the four IRAC bandpasses. We combine our results with the earlier K-band measurement of De Mooij et al., and compare them with models of the planetary emission. We find that the planet does not require the presence of an Inversion layer in the high atmosphere. This is the first very strongly irradiated planet that does not have a Temperature Inversion, which indicates that stellar or planetary characteristics other than Temperature have an important impact on Temperature Inversion. De Mooij & Snellen also detected a possible slight offset in the timing of the secondary eclipse in the K band. However, based on our four Spitzer channels, we place a 3σ upper limit of |ecos(ω)| < 0.0056, where e is the planet's orbital eccentricity and ω is the longitude of the periastron. This result strongly indicates that the orbit is circular, as expected from tidal circularization theory.
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the broadband infrared emission spectrum of the exoplanet tres 3
arXiv: Earth and Planetary Astrophysics, 2009Co-Authors: Francois Fressin, Adam Burrows, David Charbonneau, Heather A Knutson, Francis T Odonovan, Georgi Mandushev, Drake Deming, David S SpiegelAbstract:We use the Spitzer Space Telescope to estimate the dayside thermal emission of the exoplanet TrES-3 integrated in the 3.6, 4.5, 5.8, and 8.0 micron bandpasses of the Infrared Array Camera (IRAC) instrument. We observe two secondary eclipses and find relative eclipse depths of 0.00346 +/- 0.00035, 0.00372 +/- 0.00054, 0.00449 +/- 0.00097, and 0.00475 +/- 0.00046, respectively in the 4 IRAC bandpasses. We combine our results with the earlier K band measurement of De Mooij et al. (2009), and compare them with models of the planetary emission. We find that the planet does not require the presence of an Inversion layer in the high atmosphere. This is the first very strongly irradiated planet that does not have a Temperature Inversion, which indicates that stellar or planetary characteristics other than Temperature have an important impact on Temperature Inversion. De Mooij & Snellen (2009) also detected a possible slight offset in the timing of the secondary eclipse in K band. However, based on our 4 Spitzer channels, we place a 3sigma upper limit of |ecos(w)| < 0.0056 where e is the planets orbital eccentricity and w is the longitude of the periastron. This result strongly indicates that the orbit is circular, as expected from tidal circularization theory.
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Detection of Thermal Emission of XO-2b: Evidence for a Weak Temperature Inversion
The Astrophysical Journal, 2009Co-Authors: Pavel Machalek, Adam Burrows, Peter R. Mccullough, Christopher J. Burke, Joseph L. Hora, Christopher M. Johns-krullAbstract:We estimate flux ratios of the extrasolar planet XO-2b to its host star XO-2 at 3.6, 4.5, 5.8, and 8.0 μm with Infrared Array Camera on the Spitzer Space Telescope to be 0.00081 ± 0.00017, 0.00098 ± 0.00020, 0.00167 ± 0.00036, and 0.00133 ± 0.00049, respectively. The fluxes provide tentative evidence for a weak Temperature Inversion in the upper atmosphere, the precise nature of which would need to be confirmed by longer wavelength observations. XO-2b substellar flux of 0.76 × 109 erg cm–2 s–1 lies in the predicted transition region between atmospheres with and without upper atmospheric Temperature Inversion.
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detection of thermal emission of xo 2b evidence for a weak Temperature Inversion
arXiv: Solar and Stellar Astrophysics, 2009Co-Authors: Adam Burrows, Pavel Machalek, Peter R. Mccullough, Christopher J. Burke, Joseph L. Hora, Christopher M JohnskrullAbstract:We estimate flux ratios of the extrasolar planet XO-2b to its host star XO-2 at 3.6, 4.5, 5.8 and 8.0 micron with IRAC on the Spitzer Space Telescope to be 0.00081 +- 0.00017, 0.00098 +- 0.00020, 0.00167 +- 0.00036 and 0.00133 +- 0.00049, respectively. The fluxes provide tentative evidence for a weak Temperature Inversion in the upper atmosphere, the precise nature of which would need to be confirmed by longer wavelength observations. XO-2b substellar flux of 0.76 x 10^9 ergs cm^-2 s^-1 lies in the predicted transition region between atmospheres with and without upper atmospheric Temperature Inversion.
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detection of a Temperature Inversion in the broadband infrared emission spectrum of tres 4
The Astrophysical Journal, 2009Co-Authors: Heather A Knutson, Adam Burrows, David Charbonneau, Francis T Odonovan, Georgi MandushevAbstract:We estimate the strength of the bandpass-integrated thermal emission from the extrasolar planet TrES-4 at 3.6, 4.5, 5.8, and 8.0 μ using the Infrared Array Camera on the Spitzer Space Telescope. We find relative eclipse depths of 0.137% ± 0.011%, 0.148% ± 0.016%, 0.261% ± 0.059%, and 0.318% ± 0.044% in these four bandpasses, respectively. We also place a 2σ upper limit of 0.37% on the depth of the secondary eclipse in the 16 μ IRS peak-up array. These eclipse depths reveal that TrES-4 has an emission spectrum similar to that of HD 209458b, which requires the presence of water emission bands created by a thermal Inversion layer high in the atmosphere in order to explain the observed features. TrES-4 receives more radiation from its star than HD 209458b and has a correspondingly higher effective Temperature, therefore the presence of a Temperature Inversion in this planet's atmosphere lends support to the idea that Inversions might be correlated with the irradiance received by the planet. We find no evidence for any offset in the timing of the secondary eclipse, and place a 3σ upper limit of |ecos(ω)| < 0.0058, where e is the planet's orbital eccentricity and ω is the argument of pericenter. From this we conclude that tidal heating from ongoing orbital circularization is unlikely to be the explanation for TrES-4's inflated radius.
Jinqiang Zhang - One of the best experts on this subject based on the ideXlab platform.
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cloud top Temperature Inversion derived from long term radiosonde measurements at the arm twp and nsa sites
Atmospheric Research, 2020Co-Authors: Jinqiang ZhangAbstract:Abstract A Temperature Inversion layer often occurs above a cloud layer due to longwave cooling in the upper cloud levels; however, few previous studies have been conducted on the climatologic statistics of cloud-top Temperature Inversion features. By using a high-quality continuous radiosonde dataset from 2002/05 to 2014/05 at the Atmospheric Radiation Measurement (ARM) Tropical Western Pacific (TWP) site at the islands of Manus and North Slope of Alaska (NSA) site near Barrow, Alaska, this study investigated the long-term characteristics of cloud-top Temperature Inversion over the single- and double-layer clouds (SLC and DLC, respectively) in these two different geographic locations and climate regimes. Cloud tops extended much higher vertically at the TWP than at the NSA due to their different local atmospheric environments. Because of the radiative energy interactions between the two layers of clouds, a thinner Temperature Inversion depth was presented by the DLC lower clouds than by the DLC higher clouds at the TWP site. However, much weaker Temperature Inversions were detected above the DLC higher clouds than the DLC lower clouds which were often bounded by a ubiquitous surface radiative cooling-induced Inversion at the NSA site. A close Temperature Inversion was observed between the morning and evening at both sites. A thinner Temperature Inversion depth was displayed in the summer and autumn melt seasons when weak surface radiative cooling occurred at the NSA, whereas a smooth seasonal Temperature Inversion occurred at the TWP. The climatologic results of this study are expected to provide a better understanding of the complex interactions between clouds and Temperature Inversion, especially their unique climatic features in the tropics and Arctic.
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a 17 year climatology of Temperature Inversions above clouds over the arm sgp site the roles of cloud radiative effects
Atmospheric Research, 2020Co-Authors: Youtong Zheng, Jinqiang Zhang, Zhanqing Li, Hongbin ChenAbstract:Abstract Atmospheric Temperature Inversions, i.e., Temperatures increasing with altitude, modulate both radiative and buoyancy fluxes in the atmosphere. A Temperature Inversion layer often occurs immediately above a cloud layer that cools radiatively and thereby strengthens the capping Temperature Inversion. This study aims to investigate the characteristics of Temperature Inversions above clouds and their relationships with cloud-top radiative cooling. Using a 17-year (January 2001 to December 2017) high-quality and continuous radiosonde dataset collected at the Atmospheric Radiation Measurement Southern Great Plains Central Facility site, key Temperature Inversion parameters, namely, the occurrence frequency (dp), depth (dz), Temperature difference (dT), and gradient (dT/dz), are derived for single- and double-layer clouds (SLC and DLC, respectively). The occurrence frequency of Temperature Inversions above single-layer clouds decreases dramatically as cloud tops rise from low to high altitudes. When an overlying higher cloud layer is present, the Inversion becomes less frequent, shallower, and weaker than without it. This may be because higher clouds weaken the cloud-top radiative cooling of the underneath clouds by enhancing downwelling infrared radiation. This is supported by radiative transfer simulations. There are distinctive seasonal cycles of cloud-top radiative cooling for high clouds that are primarily driven by variations in shortwave heating. Distinctive seasonal cycles of Temperature Inversions also occurred regardless of the cloud regime (SLC or DLC) and altitude (low or high clouds). They appear to be driven by the seasonal cycle of cloud coverage (i.e., a greater amount of clouds undergoes stronger area-mean radiative cooling) although the shortwave heating seasonal cycle also plays a role for high clouds. Cloud radiative cooling cannot explain the diurnal cycle of Temperature Inversions.
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analysis of low level Temperature Inversions and their effects on aerosols in the lower atmosphere
Advances in Atmospheric Sciences, 2019Co-Authors: Wenying He, Pucai Wang, Zhanqing Li, Hongbin Chen, Jinqiang ZhangAbstract:High-quality and continuous radiosonde, aerosol and surface meteorology datasets are used to investigate the statistical characteristics of meteorological parameters and their effects on aerosols. The data were collected at the Atmospheric Radiation Measurement Southern Great Plains climate research facility during 2000–15. The parameters and vertical distribution of Temperature Inversion layers were found to have strong diurnal and seasonal changes. For surface-based Temperature Inversion (SBI), the mean frequency and depth of Temperature Inversion layers were 39.4% and 198 m, respectively. The Temperature difference between the top and bottom of SBI was 4.8°C, and so the Temperature gradient was 2.4°C (100 m)−1. The detailed vertical distributions of Temperature Inversion had been determined, and only the Temperature Inversion layers below 1000 m showed diurnal and seasonal variations. Mean surface aerosol number concentrations increased by 43.0%, 21.9% and 49.2% when SBIs were present at 0530, 1730 and 2330 LST, respectively. The effect of SBI on surface aerosol concentration was weakest in summer (18.1%) and strongest in winter (58.4%). During elevated Temperature Inversion events, there was no noticeable difference in surface aerosol number concentrations. Temperature differences and Temperature gradients across SBIs correlated fairly well with aerosol number concentrations, especially for Temperature gradients. The vertical distribution of aerosol optical properties with and without Temperature Inversions was different. Surface aerosol measurements were representative of the air within (below), but not above, SBIs and EIs. These results provide a basis for developing a boundary layer aerosol accumulation model and for improving radiative transfer models in the lower atmosphere.
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dynamic and thermodynamic features of low and middle clouds derived from atmospheric radiation measurement program mobile facility radiosonde data at shouxian china
Advances in Atmospheric Sciences, 2016Co-Authors: Jinqiang Zhang, Hongbin Chen, Weichyung WangAbstract:By using the radiosonde measurements collected at Shouxian, China, we examined the dynamics and thermodynamics of single- and two-layer clouds formed at low and middle levels. The analyses indicated that the horizontal wind speed above the cloud layers was higher than those within and below cloud layers. The maximum balloon ascent speed (5.3 m s−1) was located in the vicinity of the layer with the maximum cloud occurrence frequency (24.4%), indicating an upward motion (0.1–0.16 m s−1). The average thickness, magnitude and gradient of the Temperature Inversion layer above single-layer clouds were 117±94 m, 1.3±1.3°C and 1.4±1.5°C (100 m)−1, respectively. The average Temperature Inversion magnitude was the same (1.3°C) for single-low and single-middle clouds; however, a larger gradient [1.7±1.8°C (100 m)−1] and smaller thickness (94±67 m) were detected above single-low clouds relative to those above single-middle clouds [0.9±0.7°C (100 m)−1 and 157±120 m]. For the two-layer cloud, the Temperature Inversion parameters were 106±59 m, 1.0±0.9°C and 1.0±1.0°C (100 m)−1 above the upper-layer cloud and 82±60 m, 0.6±0.9°C and 0.7±0.6°C (100 m)−1 above the low-layer cloud. Absolute differences between the cloud-base height (cloud-top height) and the lifting condensation level (equilibrium level) were less than 0.5 km for 66.4% (36.8%) of the cases analyzed in summer.
Ze-wei Zhao - One of the best experts on this subject based on the ideXlab platform.
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throttling process of the kerr newman anti de sitter black holes in the extended phase space
Physical Review D, 2018Co-Authors: Ze-wei Zhao, Yi-hong XiuAbstract:The throttling process of the Kerr--Newman--anti-de Sitter (KN--AdS) black holes is systematically studied in the extended phase space. In this framework, the cosmological constant is interpreted as a varying thermodynamic pressure, and the black hole mass is identified with enthalpy. The throttling process is essentially an adiabatic and isenthalpic (i.e., constant-mass) process for the KN--AdS black holes. The Joule--Thomson coefficient, Inversion Temperature, Inversion curve, and isenthalpic curve are investigated in order, with both analytical and numerical methods. It is found that there are no maximum Inversion Temperatures, but only minimum ones that are around one half of the critical Temperatures of the KN--AdS black holes. Two characteristic masses are also discussed to show the detailed features in the throttling behaviors of the KN--AdS black holes.
Heather A Knutson - One of the best experts on this subject based on the ideXlab platform.
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the broadband infrared emission spectrum of the exoplanet tres 3
The Astrophysical Journal, 2010Co-Authors: Francois Fressin, Adam Burrows, David Charbonneau, Heather A Knutson, Francis T Odonovan, Georgi Mandushev, Drake Deming, David S SpiegelAbstract:We use the Spitzer Space Telescope to estimate the dayside thermal emission of the exoplanet TrES-3 integrated in the 3.6, 4.5, 5.8, and 8.0 μm bandpasses of the Infrared Array Camera (IRAC) instrument. We observe two secondary eclipses and find relative eclipse depths of 0.00346 ± 0.00035, 0.00372 ± 0.00054, 0.00449 ± 0.00097, and 0.00475 ± 0.00046, respectively, in the four IRAC bandpasses. We combine our results with the earlier K-band measurement of De Mooij et al., and compare them with models of the planetary emission. We find that the planet does not require the presence of an Inversion layer in the high atmosphere. This is the first very strongly irradiated planet that does not have a Temperature Inversion, which indicates that stellar or planetary characteristics other than Temperature have an important impact on Temperature Inversion. De Mooij & Snellen also detected a possible slight offset in the timing of the secondary eclipse in the K band. However, based on our four Spitzer channels, we place a 3σ upper limit of |ecos(ω)| < 0.0056, where e is the planet's orbital eccentricity and ω is the longitude of the periastron. This result strongly indicates that the orbit is circular, as expected from tidal circularization theory.
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the broadband infrared emission spectrum of the exoplanet tres 3
arXiv: Earth and Planetary Astrophysics, 2009Co-Authors: Francois Fressin, Adam Burrows, David Charbonneau, Heather A Knutson, Francis T Odonovan, Georgi Mandushev, Drake Deming, David S SpiegelAbstract:We use the Spitzer Space Telescope to estimate the dayside thermal emission of the exoplanet TrES-3 integrated in the 3.6, 4.5, 5.8, and 8.0 micron bandpasses of the Infrared Array Camera (IRAC) instrument. We observe two secondary eclipses and find relative eclipse depths of 0.00346 +/- 0.00035, 0.00372 +/- 0.00054, 0.00449 +/- 0.00097, and 0.00475 +/- 0.00046, respectively in the 4 IRAC bandpasses. We combine our results with the earlier K band measurement of De Mooij et al. (2009), and compare them with models of the planetary emission. We find that the planet does not require the presence of an Inversion layer in the high atmosphere. This is the first very strongly irradiated planet that does not have a Temperature Inversion, which indicates that stellar or planetary characteristics other than Temperature have an important impact on Temperature Inversion. De Mooij & Snellen (2009) also detected a possible slight offset in the timing of the secondary eclipse in K band. However, based on our 4 Spitzer channels, we place a 3sigma upper limit of |ecos(w)| < 0.0056 where e is the planets orbital eccentricity and w is the longitude of the periastron. This result strongly indicates that the orbit is circular, as expected from tidal circularization theory.
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detection of a Temperature Inversion in the broadband infrared emission spectrum of tres 4
The Astrophysical Journal, 2009Co-Authors: Heather A Knutson, Adam Burrows, David Charbonneau, Francis T Odonovan, Georgi MandushevAbstract:We estimate the strength of the bandpass-integrated thermal emission from the extrasolar planet TrES-4 at 3.6, 4.5, 5.8, and 8.0 μ using the Infrared Array Camera on the Spitzer Space Telescope. We find relative eclipse depths of 0.137% ± 0.011%, 0.148% ± 0.016%, 0.261% ± 0.059%, and 0.318% ± 0.044% in these four bandpasses, respectively. We also place a 2σ upper limit of 0.37% on the depth of the secondary eclipse in the 16 μ IRS peak-up array. These eclipse depths reveal that TrES-4 has an emission spectrum similar to that of HD 209458b, which requires the presence of water emission bands created by a thermal Inversion layer high in the atmosphere in order to explain the observed features. TrES-4 receives more radiation from its star than HD 209458b and has a correspondingly higher effective Temperature, therefore the presence of a Temperature Inversion in this planet's atmosphere lends support to the idea that Inversions might be correlated with the irradiance received by the planet. We find no evidence for any offset in the timing of the secondary eclipse, and place a 3σ upper limit of |ecos(ω)| < 0.0058, where e is the planet's orbital eccentricity and ω is the argument of pericenter. From this we conclude that tidal heating from ongoing orbital circularization is unlikely to be the explanation for TrES-4's inflated radius.
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detection of a Temperature Inversion in the broadband infrared emission spectrum of tres 4
arXiv: Astrophysics, 2008Co-Authors: Heather A Knutson, Adam Burrows, David Charbonneau, Francis T Odonovan, Georgi MandushevAbstract:We estimate the strength of the bandpass-integrated thermal emission from the extrasolar planet TrES-4 at 3.6, 4.5, 5.8, and 8.0 micron using the Infrared Array Camera (IRAC) on the Spitzer Space Telescope. We find relative eclipse depths of 0.137 +/- 0.011%, 0.148 +/- 0.016%, 0.261 +/- 0.059%, and 0.318 +/- 0.044% in these four bandpasses, respectively. We also place a 2 sigma upper limit of 0.37% on the depth of the secondary eclipse in the 16 micron IRS peak-up array. These eclipse depths reveal that TrES-4 has an emission spectrum similar to that of HD 209458b, which requires the presence of water emission bands created by an thermal Inversion layer high in the atmosphere in order to explain the observed features. TrES-4 receives more radiation from its star than HD 209458b and has a correspondingly higher effective Temperature, therefore the presence of a Temperature Inversion in this planet's atmosphere lends support to the idea that Inversions might be correlated with the irradiance received by the planet. We find no evidence for any offset in the timing of the secondary eclipse, and place a 3 sigma upper limit of |ecos(omega)|<0.0058 where e is the planet's orbital eccentricity and omega is the argument of pericenter. From this we conclude that tidal heating from ongoing orbital circulatization is unlikely to be the explanation for TrES-4's inflated radius.
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the 3 6 8 0 μm broadband emission spectrum of hd 209458b evidence for an atmospheric Temperature Inversion
The Astrophysical Journal, 2008Co-Authors: Heather A Knutson, Adam Burrows, David Charbonneau, Lori E Allen, Thomas S MegeathAbstract:We estimate the strength of the bandpass-integrated thermal emission from the extrasolar planet HD 209458b at 3.6, 4.5, 5.8, and 8.0 μm using the Infrared Array Camera (IRAC) on the Spitzer Space Telescope. We observe a single secondary eclipse simultaneously in all four bandpasses and find relative eclipse depths of 0.00094 ± 0.00009, 0.00213 ± 0.00015, 0.00301 ± 0.00043, and 0.00240 ± 0.00026, respectively. These eclipse depths reveal that the shape of the inferred emission spectrum for the planet differs significantly from the predictions of standard atmosphere models; instead, the most plausible explanation would require the presence of an Inversion layer high in the atmosphere leading to significant water emission in the 4.5 and 5.8 μm bandpasses. This is the first clear indication of such a Temperature Inversion in the atmosphere of a hot Jupiter, as previous observations of other planets appeared to be in reasonably good agreement with the predictions of models without such an Inversion layer.
