1,721,418 research outputs found
HD 21520 b: a warm sub-Neptune transiting a bright G dwarf
Get PDFWe report the discovery and validation of HD 21520 b, a transiting planet found with TESS and orbiting a bright G dwarf (V=9.2, Tef f = 5871±62 K, R⋆ = 1.04±0.02 R⊙). HD 21520 b was originally alerted as a system (TOI-4320) consisting of two planet candidates with periods of 703.6 and 46.4 days. However, our analysis supports instead a single-planet system with an orbital period of 25.1292±0.0001 days and radius of 2.70 ± 0.09 R⊕. Three full transits in sectors 4, 30 and 31 match this period and have transit depths and durations in agreement with each other, as does a partial transit in sector 3. We also observe transits using CHEOPS and LCOGT. SOAR and Gemini high-resolution imaging do not indicate the presence of any nearby companions, and Minerva-Australis and CORALIE radial velocities rule out an on-target spectroscopic binary. Additionally, we use ESPRESSO radial velocities to obtain a tentative mass measurement of 7.9 +3.2 −3.0 M⊕, with a 3-σ upper limit of 17.7 M⊕. Due to the bright nature of its host and likely significant gas envelope of the planet, HD 21520 b is a promising candidate for further mass measurements and for atmospheric characterization
HD 21520 b: a warm sub-Neptune transiting a bright G dwarf
No full textWe report the discovery and validation of HD 21520 b, a transiting planet found with TESS and orbiting a bright G dwarf (V=9.2, Teff = 5871 ± 62 K, R⋆ = 1.04 ± 0.02 R⊙). HD 21520 b was originally alerted as a system (TOI-4320) consisting of two planet candidates with periods of 703.6 and 46.4 days. However, our analysis supports instead a single-planet system with an orbital period of 25.1292 ± 0.0001 days and radius of 2.70 ± 0.09 R⊕. Three full transits in sectors 4, 30 and 31 match this period and have transit depths and durations in agreement with each other, as does a partial transit in sector 3. We also observe transits using CHEOPS and LCOGT. SOAR and Gemini high-resolution imaging do not indicate the presence of any nearby companions, and Minerva-Australis and CORALIE radial velocities rule out an on-target spectroscopic binary. Additionally, we use ESPRESSO radial velocities to obtain a tentative mass measurement of 7.9^{+3.2}_{-3.0}\, M_{\hbox{\oplus }}, with a 3-σ upper limit of 17.7 M⊕. Due to the bright nature of its host and likely significant gas envelope of the planet, HD 21520 b is a promising candidate for further mass measurements and for atmospheric characterization
HD 21520 b: a warm sub-Neptune transiting a bright G dwarf
Get PDFWe report the discovery and validation of HD 21520 b, a transiting planet
found with TESS and orbiting a bright G dwarf (V=9.2,
K, ). HD 21520 b was originally alerted
as a system (TOI-4320) consisting of two planet candidates with periods of
703.6 and 46.4 days. However, our analysis supports instead a single-planet
system with an orbital period of days and radius of . Three full transits in sectors 4, 30 and 31 match this
period and have transit depths and durations in agreement with each other, as
does a partial transit in sector 3. We also observe transits using CHEOPS and
LCOGT. SOAR and Gemini high-resolution imaging do not indicate the presence of
any nearby companions, and MINERVA-Australis and CORALIE radial velocities rule
out an on-target spectroscopic binary. Additionally, we use ESPRESSO radial
velocities to obtain a tentative mass measurement of , with a 3- upper limit of 17.7 . Due to the
bright nature of its host and likely significant gas envelope of the planet, HD
21520 b is a promising candidate for further mass measurements and for
atmospheric characterization.Comment: Submitted to MNRA
A Systematic Algorithm for the Design of Hybrid Waveguide-Microstrip Transversal Microwave Filters
Get PDFA novel algorithm to design hybrid waveguide-microstrip transversal microwave filters is proposed in this study. The
idea consists in isolating each resonator involved in the filter structure, to synthesise individually its frequency response, both in
resonant frequency and bandwidth. These separated optimisations lead to the dimensions of the filtering structure to meet the
requirements of a certain, specified transfer function. The novel algorithm introduces an iterative procedure in order to
synthesise the direct coupling term between source and load, which is always present in the hybrid filter structure. The whole
algorithm is illustrated by means of a design example, where a very good agreement between the ideal specified transfer
function and the final frequency response of the designed hybrid filter is obtained. A second different design example, which
has been manufactured and tested, is also included for validation.Ministerio de Educación y Ciencia, Ref. TEC2010-21520-C04-0
Extended-stopband microstrip lowpass filter using rat-race directional couplers
No full textA class of microstrip lowpass filter (LPF) with a sharp-rejection, ultra-broad stopband is reported. It employs rat-race directional couplers properly arranged to operate as bandstop transversal filtering sections (TFSs). The theoretical foundations of this LPF approach are described, and the performance control of its building bandstop TFS is verified. Moreover, a proof-of-concept microstrip LPF prototype with a 3 dB cutoff frequency of 1 GHz and a 20 dB stopband up to 5.86 GHz has been built and tested.This work has been supported in part by the ‘Centro de Investigación Científica y Tecnológica (CICYT)’ under the Spanish National Projects TEC2010-21520-C04-02 and TEC2010-21520-C04-04, in part by the Regional Project UAH2011/EXP-025, and in part by a research grant from the Generalitat Valenciana
A Simple CRLH LWA Circuit Condition for Constant Radiation Rate
Get PDFAbstract--A simple analytical condition for the radiation resistance and conductance (R,G) of an equivalent composite right/
left-handed (CRLH) balanced leaky-wave antenna unit-cell is proposed to achieve a constant radiation rate. Similar to the CRLH
"balanced condition," which allows a smooth phase transition from
the left-handed to the right-handed frequency regions, the proposed condition provides a continuous and smooth transition
of the radiation losses from the left-handed to the right-handed frequency region. Moreover, this condition also solves the phase fluctuations that traditionally occur around the CRLH transition frequency due to real radiation losses. Several numerical results are
included to confirm the uniform radiation rate obtained when the
new derived condition is used.Ministerio de Educación y Ciencia, Ref. TEC2010-21520-C04-0
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Get PDF“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
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