18 research outputs found
Heating of quiescent coronal loops caused by nearby eruptions observed with the Solar Dynamics Observatory and the Solar Upper Transition Region Imager
How structures, e.g., magnetic loops, in the upper atmosphere, i.e., the
transition region and corona, are heated and sustained is one of the major
unresolved issues in solar and stellar physics. Various theoretical and
observational studies on the heating of coronal loops have been undertaken. The
heating of quiescent loops caused by eruptions is, however, rarely observed. In
this study, employing data from the Solar Dynamics Observatory (SDO) and Solar
Upper Transition Region Imager (SUTRI), we report the heating of quiescent
loops associated with nearby eruptions. In active regions (ARs) 13092 and
13093, a long filament and a short filament, and their overlying loops are
observed on 2022 September 4. In AR 13093, a warm channel erupted toward the
northeast, whose material moved along its axis toward the northwest under the
long filament, turned to the west above the long filament, and divided into two
branches falling to the solar surface. Subsequently, the short filament erupted
toward the southeast. Associated with these two eruptions, the quiescent loops
overlying the long filament appeared in SDO/Atmospheric Imaging Assembly (AIA)
high-temperature images, indicating the heating of loops. During the heating,
signature of magnetic reconnection between loops is identified, including the
inflowing motions of loops, and the formation of X-type structures and newly
reconnected loops. The heated loops then cooled down. They appeared
sequentially in AIA and SUTRI lower-temperature images. All the results suggest
that the quiescent loops are heated by reconnection between loops caused by the
nearby warm channel and filament eruptions.Comment: 20 pages, 12 figures, accepted for publication in Ap
A Type II Radio Burst Driven by a Blowout Jet on the Sun
Type II radio bursts are often associated with coronal shocks that are
typically driven by coronal mass ejections (CMEs) from the Sun. Here, we
conduct a case study of a type II radio burst that is associated with a C4.5
class flare and a blowout jet, but without the presence of a CME. The blowout
jet is observed near the solar disk center in the extreme-ultraviolet (EUV)
passbands with different characteristic temperatures. Its evolution involves an
initial phase and an ejection phase with a velocity of 560 km/s. Ahead of the
jet front, an EUV wave propagates at a projected velocity of 403 km/s in the
initial stage. The moving velocity of the source region of the type II radio
burst is estimated to be 641 km/s, which corresponds to the shock velocity
against the coronal density gradient. The EUV wave and the type II radio burst
are closely related to the ejection of the blowout jet, suggesting that both
are likely the manifestation of a coronal shock driven by the ejection of the
blowout jet. The type II radio burst likely starts lower than those associated
with CMEs. The combination of the velocities of the radio burst and the EUV
wave yields a modified shock velocity at 757 km/s. The Alfven Mach number is in
the range of 1.09-1.18, implying that the shock velocity is 10%-20% larger than
the local Alfven velocity.Comment: Accepted by ApJ, 17 pages, and 6 figure
Observation of two splitting processes in a partial filament eruption on the sun: the role of breakout reconnection
Partial filament eruptions have often been observed, however, the physical
mechanisms that lead to filament splitting are not yet fully understood. In
this study, we present a unique event of a partial filament eruption that
undergoes two distinct splitting processes. The first process involves vertical
splitting and is accompanied by brightenings inside the filament, which may
result from internal magentic reconnection within the filament. Following the
first splitting process, the filament is separated into an upper part and a
lower part. Subsequently, the upper part undergoes a second splitting, which is
accompanied by a coronal blowout jet. An extrapolation of the coronal magnetic
field reveals a hyperbolic flux tube structure above the filament, indicating
the occurrence of breakout reconnection that reduces the constraning field
above. Consequently, the filament is lifted up, but at a nonuniform speed. The
high-speed part reaches the breakout current sheet to generate the blowout jet,
while the low-speed part falls back to the solar surface, resulting in the
second splitting. In addition, continuous brightenings are observed along the
flare ribbons, suggesting the occurrence of slipping reconnection process. This
study presents, for the first time, the unambiguous observation of a two-stage
filament splitting process, advancing our understanding of the complex dynamics
of solar eruptions.Comment: 12 pages, 8 figure
Traveling kink oscillations of coronal loops launched by a solar flare
We investigate the traveling kink oscillation triggered by a solar flare on
2022 September 29. The observational data is mainly measured by the Solar Upper
Transition Region Imager (SUTRI), the Atmospheric Imaging Assembly (AIA), and
the Spectrometer/Telescope for Imaging X-rays (STIX). The transverse
oscillations with apparent decaying in amplitudes, which are nearly
perpendicular to the oscillating loop, are observed in passbands of SUTRI 465
A, AIA 171 A, and 193 A. The decaying oscillation is launched by a solar flare
erupted closely to one footpoint of coronal loops, and then it propagates along
several loops. Next, the traveling kink wave is evolved to a standing kink
oscillation. To the best of our knowledge, this is the first report of the
evolution of a traveling kink pulse to a standing kink wave along coronal
loops. The standing kink oscillation along one coronal loop has a similar
period of about 6.3 minutes at multiple wavelengths, and the decaying time is
estimated to about 9.6-10.6 minutes. Finally, two dominant periods of 5.1
minutes and 2.0 minutes are detected in another oscillating loop, suggesting
the coexistence of the fundamental and third harmonics.Comment: 8 pages, 8 figures, accepted by A&
Solar Ring Mission: Building a Panorama of the Sun and Inner-heliosphere
Solar Ring (SOR) is a proposed space science mission to monitor and study the
Sun and inner heliosphere from a full 360{\deg} perspective in the ecliptic
plane. It will deploy three 120{\deg}-separated spacecraft on the 1-AU orbit.
The first spacecraft, S1, locates 30{\deg} upstream of the Earth, the second,
S2, 90{\deg} downstream, and the third, S3, completes the configuration. This
design with necessary science instruments, e.g., the Doppler-velocity and
vector magnetic field imager, wide-angle coronagraph, and in-situ instruments,
will allow us to establish many unprecedented capabilities: (1) provide
simultaneous Doppler-velocity observations of the whole solar surface to
understand the deep interior, (2) provide vector magnetograms of the whole
photosphere - the inner boundary of the solar atmosphere and heliosphere, (3)
provide the information of the whole lifetime evolution of solar featured
structures, and (4) provide the whole view of solar transients and space
weather in the inner heliosphere. With these capabilities, Solar Ring mission
aims to address outstanding questions about the origin of solar cycle, the
origin of solar eruptions and the origin of extreme space weather events. The
successful accomplishment of the mission will construct a panorama of the Sun
and inner-heliosphere, and therefore advance our understanding of the star and
the space environment that holds our life.Comment: 41 pages, 6 figures, 1 table, to be published in Advances in Space
Researc
Space advanced technology demonstration satellite
The Space Advanced Technology demonstration satellite (SATech-01), a mission for low-cost space science and new technology experiments, organized by Chinese Academy of Sciences (CAS), was successfully launched into a Sun-synchronous orbit at an altitude of similar to 500 km on July 27, 2022, from the Jiuquan Satellite Launch Centre. Serving as an experimental platform for space science exploration and the demonstration of advanced common technologies in orbit, SATech-01 is equipped with 16 experimental payloads, including the solar upper transition region imager (SUTRI), the lobster eye imager for astronomy (LEIA), the high energy burst searcher (HEBS), and a High Precision Magnetic Field Measurement System based on a CPT Magnetometer (CPT). It also incorporates an imager with freeform optics, an integrated thermal imaging sensor, and a multi-functional integrated imager, etc. This paper provides an overview of SATech-01, including a technical description of the satellite and its scientific payloads, along with their on-orbit performance
Three types of proteinases in Japanese common squid Todarodes pacificus hepatopancreas as studied by using carp myofibrils as substrate
Three types of proteinases, namely cysteine-, metallo-, and serine-proteinases, were found in squid hepatopancreas by studying the inhibition spectra using carp myofibril as substrate. The cysteine-, metallo-, and serine-types showed the highest activities at 50℃, 35℃, and 40℃, respectively. The optimal pHs were pH 5, pH 7, and pH 9 for the cysteine-, metallo-, and serine-types, respectively. When assayed at 20℃ and pH 7.5, the metallo-type showed the highest activity. The metallo-type was characterized by a high selectivity in the digestion of myosin. Among the three enzymes, the cysteine-type was found to be the most stable against thermal and acid treatments. Heat treated myofibrils were more susceptible to cysteine- and serine-types, but less susceptible to the metallo-type. Acid treatment of myofibrils also enhanced the digestibility by cysteine type. The results indicated that the cysteine-type seemed to be the most suitable enzyme to produce peptides from denatured myofibrils by their random digestion
Nutritional and Digestive Properties of Protein Isolates Extracted from the Muscle of the Common Carp Using pH-Shift Processing
Centro de experimentación medioambienta
Structural and functional characterization of CATH_BRALE, the defense molecule in the ancient salmonoid, Brachymystax lenok
Thick-lipped lenok, Brachymystax lenok is one of the ancient fish species in China and northeast Asia countries. Due to the overfishing, the population of lenok has been declined significantly. Cathelicidins are innate immune effectors that possess both bactericidal activities and immunomodulatory functions. This report identifies and characterizes the salmonoid cathelicidin (CATH_BRALE) from this ancient fish. It consists of open reading frame (ORF) of 886 bp encoding the putative peptide of 199 amino acids. Sequence alignment with other representative salmonid cathelicidins displayed two distinctive features of current lenok cathelicidin: high level of arginine, resulting in high positive charge and glycine residues, which is significantly different from most acknowledged types of cathelicidins; and the six-amino-acid tandem repeated sequence of RPGGGS detected in a variable number of copies among fish cathelicidins, suggesting the existence of a genetically unstable region similar to that found in some mammalian cathelicidins. Expression of CATH_BRALE is predominantly found in gill, with lower levels in the gastrointestinal tract and spleen. The homology modeled structure of CATH_BRALE exhibits structural features of antiparallel beta-sheets flanked by alpha-helices that are representative of small cationic cathelicidin family peptides. CATH_BRALE possesses much stronger antimicrobial activity against gram-negative bacteria than that of the human ortholog, LL-37. The growth of two typical fish bacterial pathogens, gram-negative bacterium of Aeromonas salmonicida and Aeromonas hydrophila was substantially inhibited by synthetic CATH_BRALE, with both MICs as low as 9.38 mu M. (c) 2012 Elsevier Ltd. All rights reserved.Thick-lipped lenok, Brachymystax lenok is one of the ancient fish species in China and northeast Asia countries. Due to the overfishing, the population of lenok has been declined significantly. Cathelicidins are innate immune effectors that possess both bactericidal activities and immunomodulatory functions. This report identifies and characterizes the salmonoid cathelicidin (CATH_BRALE) from this ancient fish. It consists of open reading frame (ORF) of 886 bp encoding the putative peptide of 199 amino acids. Sequence alignment with other representative salmonid cathelicidins displayed two distinctive features of current lenok cathelicidin: high level of arginine, resulting in high positive charge and glycine residues, which is significantly different from most acknowledged types of cathelicidins; and the six-amino-acid tandem repeated sequence of RPGGGS detected in a variable number of copies among fish cathelicidins, suggesting the existence of a genetically unstable region similar to that found in some mammalian cathelicidins. Expression of CATH_BRALE is predominantly found in gill, with lower levels in the gastrointestinal tract and spleen. The homology modeled structure of CATH_BRALE exhibits structural features of antiparallel beta-sheets flanked by alpha-helices that are representative of small cationic cathelicidin family peptides. CATH_BRALE possesses much stronger antimicrobial activity against gram-negative bacteria than that of the human ortholog, LL-37. The growth of two typical fish bacterial pathogens, gram-negative bacterium of Aeromonas salmonicida and Aeromonas hydrophila was substantially inhibited by synthetic CATH_BRALE, with both MICs as low as 9.38 mu M. (c) 2012 Elsevier Ltd. All rights reserved
A Type II Radio Burst Driven by a Blowout Jet on the Sun
Type II radio bursts are often associated with coronal shocks that are typically driven by coronal mass ejections (CMEs) from the Sun. Here we conduct a case study of a type II radio burst that is associated with a C4.5-class flare and a blowout jet, but without the presence of a CME. The blowout jet is observed near the solar disk center in the extreme-ultraviolet (EUV) passbands with different characteristic temperatures. Its evolution involves an initial phase and an ejection phase with a velocity of 560 ± 87 km s ^−1 . Ahead of the jet front, an EUV wave propagates at a projected velocity of ∼403 ± 84 km s ^−1 in the initial stage. The velocity of the type II radio burst is estimated to be ∼641 km s ^−1 , which corresponds to the shock velocity against the coronal density gradient. The EUV wave and the type II radio burst are closely related to the ejection of the blowout jet, suggesting that both are likely the manifestation of a coronal shock driven by the ejection of the blowout jet. The type II radio burst likely starts lower than those associated with CMEs. The combination of the velocities of the radio burst and the EUV wave yields a modified shock velocity at ∼757 km s ^−1 . The Alfvén Mach number is in the range of 1.09–1.18, implying that the shock velocity is 10%–20% larger than the local Alfvén velocity