27 research outputs found
htof::A New Open-source Tool for Analyzing Hipparcos, Gaia, and Future Astrometric Missions
We present htof, an open-source tool for interpreting and fitting the
intermediate astrometric data (IAD) from both the 1997 and 2007 reductions of
Hipparcos, the scanning-law of Gaia, and future missions such as the Nancy
Grace Roman Space Telescope (NGRST). htof solves for the astrometric parameters
of any system for any arbitrary combination of absolute astrometric missions.
In preparation for later Gaia data releases, htof supports arbitrarily
high-order astrometric solutions (e.g. five-, seven-, nine-parameter fits).
Using htof, we find that the IAD of 6617 sources in Hipparcos 2007 might have
been affected by a data corruption issue. htof integrates an ad-hoc correction
that reconciles the IAD of these sources with their published catalog
solutions. We developed htof to study masses and orbital parameters of
sub-stellar companions, and we outline its implementation in one orbit fitting
code (orvara, https://github.com/t-brandt/orvara). We use htof to predict a
range of hypothetical additional planets in the ~Pic system, which could
be detected by coupling NGRST astrometry with Gaia and Hipparcos. htof is pip
installable and available at https://github.com/gmbrandt/htof .Comment: Accepted to AJ. References updated in version 2. The Hipparcos 2007
Re-reduction Java Tool Intermediate Astrometric Data are available at , via
the "zip file" link at https://www.cosmos.esa.int/web/hipparcos/hipparcos-2 :
"...human readable version of the IAD of the Java tool in a zip file
[warning: ~350 MB]...
orvara::An Efficient Code to Fit Orbits using Radial Velocity, Absolute, and/or Relative Astrometry
We present an open-source Python package, Orbits from Radial Velocity,
Absolute, and/or Relative Astrometry (orvara), to fit Keplerian orbits to any
combination of radial velocity, relative astrometry, and absolute astrometry
data from the Hipparcos-Gaia Catalog of Accelerations. By combining these three
data types, one can measure precise masses and sometimes orbital parameters
even when the observations cover a small fraction of an orbit. orvara achieves
its computational performance with an eccentric anomaly solver five to ten
times faster than commonly used approaches, low-level memory management to
avoid python overheads, and by analytically marginalizing out parallax,
barycenter proper motion, and the instrument-specific radial velocity zero
points. Through its integration with the Hipparcos and Gaia intermediate
astrometry package htof, orvara can properly account for the epoch astrometry
measurements of Hipparcos and the measurement times and scan angles of
individual Gaia epochs. We configure orvara with modifiable .ini configuration
files tailored to any specific stellar or planetary system. We demonstrate
orvara with a case study application to a recently discovered white dwarf/main
sequence (WD/MS) system, HD 159062. By adding absolute astrometry to literature
RV and relative astrometry data, our comprehensive MCMC analysis improves the
precision of HD 159062B's mass by more than an order of magnitude to
. We also derive a low eccentricity and
large semimajor axis, establishing HD 159062AB as a system that did not
experience Roche lobe overflow.Comment: 24 pages, 5 figures, 5 tables. AJ accepted with minor changes. orvara
is available at https://github.com/t-brandt/orvar
Precise Masses and Orbits for Nine Radial Velocity Exoplanets
Radial velocity (RV) surveys have discovered hundreds of exoplanetary systems
but suffer from a fundamental degeneracy between planet mass and orbital
inclination . In this paper we break this degeneracy by combining RVs with
complementary absolute astrometry taken from the Gaia EDR3 version of the
cross-calibrated Hipparcos-Gaia Catalog of Accelerations (HGCA). We use the
Markov Chain Monte Carlo orbit code to simultaneously fit
literature RVs and absolute astrometry from the HGCA. We constrain the orbits,
masses, and inclinations of nine single and massive RV companions orbiting
nearby G and K stars. We confirm the planetary nature of six companions: HD
29021 b (), HD 81040 b
(), HD 87883 b (), HD 98649 b (), HD 106252 b
(), and HD 171238 b
(). We place one companion, HD 196067 b
() on the planet-brown dwarf boundary, and two
companions in the low mass brown dwarf regime: HD 106515 Ab
(), and HD 221420 b
(). The brown dwarf HD 221420 b, with a
semi-major axis of AU, a period of
years, and an eccentricity of
represents a promising target for high-contrast imaging. The RV orbits of HD
87883 b, HD 98649 b, HD 171238 b, and HD 196067 b are not fully constrained yet
because of insufficient RV data. We find two possible inclinations for each of
these orbits due to difficulty in separating prograde from retrograde orbits,
but we expect this will change decisively with future Gaia data releases
The Gliese 86 Binary System: A Warm Jupiter Formed in a Disk Truncated at approximate to 2 au
Gliese 86 is a nearby K dwarf hosting a giant planet on a ≈16 day orbit and an outer white dwarf companion on a ≈century-long orbit. In this study we combine radial velocity data (including new measurements spanning more than a decade) with high angular resolution imaging and absolute astrometry from Hipparcos and Gaia to measure the current orbits and masses of both companions. We then simulate the evolution of the Gl 86 system to constrain its primordial orbit when both stars were on the main sequence; the closest approach between the two stars was then about 9 au. Such a close separation limited the size of the protoplanetary disk of Gl 86 A and dynamically hindered the formation of the giant planet around it. Our measurements of Gl 86 B and Gl 86 Ab’s orbits reveal Gl 86 as a system in which giant planet formation took place in a disk truncated at ≈2 au. Such a disk would be just big enough to harbor the dust mass and total mass needed to assemble Gl 86 Ab’s core and envelope, assuming a high disk accretion rate and a low viscosity. Inefficient accretion of the disk onto Gl 86 Ab, however, would require a disk massive enough to approach the Toomre stability limit at its outer truncation radius. The orbital architecture of the Gl 86 system shows that giant planets can form even in severely truncated disks and provides an important benchmark for planet formation theory
The Gliese 86 Binary System: A Warm Jupiter Formed in a Disk Truncated at ≈2 au
© 2022. The Author(s). Published by the American Astronomical Society. This is an open access article distributed under the Creative Commons Attribution License, to view a copy of the license, see: https://creativecommons.org/licenses/by/4.0/Gliese 86 is a nearby K dwarf hosting a giant planet on a ≈16 day orbit and an outer white dwarf companion on a ≈century-long orbit. In this study we combine radial velocity data (including new measurements spanning more than a decade) with high angular resolution imaging and absolute astrometry from Hipparcos and Gaia to measure the current orbits and masses of both companions. We then simulate the evolution of the Gl 86 system to constrain its primordial orbit when both stars were on the main sequence; the closest approach between the two stars was then about 9 au. Such a close separation limited the size of the protoplanetary disk of Gl 86 A and dynamically hindered the formation of the giant planet around it. Our measurements of Gl 86 B and Gl 86 Ab’s orbits reveal Gl 86 as a system in which giant planet formation took place in a disk truncated at ≈2 au. Such a disk would be just big enough to harbor the dust mass and total mass needed to assemble Gl 86 Ab’s core and envelope, assuming a high disk accretion rate and a low viscosity. Inefficient accretion of the disk onto Gl 86 Ab, however, would require a disk massive enough to approach the Toomre stability limit at its outer truncation radius. The orbital architecture of the Gl 86 system shows that giant planets can form even in severely truncated disks and provides an important benchmark for planet formation theory.Peer reviewe
The Gliese 86 Binary System: A Warm Jupiter Formed in a Disk Truncated at ≈2 au
Gliese 86 is a nearby K dwarf hosting a giant planet on a ≍16 day orbit and an outer white dwarf companion on a ≍century-long orbit. In this study we combine radial velocity data (including new measurements spanning more than a decade) with high angular resolution imaging and absolute astrometry from Hipparcos and Gaia to measure the current orbits and masses of both companions. We then simulate the evolution of the Gl 86 system to constrain its primordial orbit when both stars were on the main sequence; the closest approach between the two stars was then about 9 au. Such a close separation limited the size of the protoplanetary disk of Gl 86 A and dynamically hindered the formation of the giant planet around it. Our measurements of Gl 86 B and Gl 86 Ab's orbits reveal Gl 86 as a system in which giant planet formation took place in a disk truncated at ≍2 au. Such a disk would be just big enough to harbor the dust mass and total mass needed to assemble Gl 86 Ab's core and envelope, assuming a high disk accretion rate and a low viscosity. Inefficient accretion of the disk onto Gl 86 Ab, however, would require a disk massive enough to approach the Toomre stability limit at its outer truncation radius. The orbital architecture of the Gl 86 system shows that giant planets can form even in severely truncated disks and provides an important benchmark for planet formation theory
Roles of DNA Methylation in Color Alternation of Eastern Honey Bees (<i>Apis cerana</i>) Induced by the Royal Jelly of Western Honey Bees (<i>Apis mellifera</i>)
Honey bees have a very interesting phenomenon where the larval diets of two different honey bee species are exchanged, resulting in altered phenotypes, namely, a honey bee nutritional crossbreed. This is a classical epigenetic process, but its underlying mechanisms remain unclear. This study aims to investigate the contribution of DNA methylation to the phenotypic alternation of a Apis mellifera–Apis cerana nutritional crossbreed. We used a full nutritional crossbreed technique to rear A. cerana queens by feeding their larvae with A. mellifera royal-jelly-based diets in an incubator. Subsequently, we compared genome-wide methylation sequencing, body color, GC ratio, and the DMRs between the nutritional crossbreed, A. cerana queens (NQs), and control, A. cerana queens (CQs). Our results showed that the NQ’s body color shifted to yellow compared to the black control queens. Genome methylation sequencing revealed that NQs had a much higher ratio of mCG than that of CQs. A total of 1020 DMGs were identified, of which 20 DMGs were enriched into key pathways for melanin synthesis, including tryptophan, tyrosine, dopamine, and phenylalanine KEGG pathways. Three key differentially methylated genes [OGDH, ALDH(NAD+) and ALDH7] showed a clear, altered DNA methylation in multiple CpG islands in NQs compared to CQs. Consequently, these findings revealed that DNA methylation participates in A. cerana–A. mellifera nutritional crossbreeding as an important epigenetic modification. This study serves as a model of cross-kingdom epigenetic mechanisms in insect body color induced by environmental factors
URG11 Regulates Prostate Cancer Cell Proliferation, Migration, and Invasion
Upregulated gene 11 (URG11), a new gene upregulated by hepatitis B virus X protein, is involved in the development and progression of several tumors, including liver, stomach, lung, and colon cancers. However, the role of URG11 in prostate cancer remains yet to be elucidated. By determined expression in human prostate cancer tissues, URG11 was found significantly upregulated and positively correlated with the severity of prostate cancer, compared with that in benign prostatic hyperplasia tissues. Further, the mRNA and protein levels of URG11 were significantly upregulated in human prostate cancer cell lines (DU145, PC3, and LNCaP), compared with human prostate epithelial cell line (RWPE-1). Moreover, by the application of siRNA against URG11, the proliferation, migration, and invasion of prostate cancer cells were markedly inhibited. Genetic knockdown of URG11 also induced cell cycle arrest at G1/S phase, induced apoptosis, and decreased the expression level of β-catenin in prostate cancer cells. Overexpression of URG11 promoted the expression of β-catenin, the growth, the migration, and invasion ability of prostate cancer cells. Taken together, this study reveals that URG11 is critical for the proliferation, migration, and invasion in prostate cancer cells, providing the evidence of URG11 to be a novel potential therapeutic target of prostate cancer
Data_Sheet_1_Effects of g-C3N4 on bacterial community and tetracycline resistance genes in two typical sediments in tetracycline pollution remediation.pdf
Photocatalysis, as a novel technique, has been widely used for antibiotic pollution remediation in wastewater. In the processes of degradation and removal of antibiotics, the impact of photocatalysts on microenvironment is very important but remains poorly understood. In the present study, the effect of typical photocatalyst g-C3N4 (Graphitic carbon nitride) on microbial community was investigated in two sediment types (riverbed sediment and pig-farm sediment) polluted by tetracycline (TC) in central southern China. The riverbed sediment and pig farm sediment samples were respectively exposed to g-C3N4 (25, 75, 125 mg⋅kg–1) and TC (60, 120, 180 mg⋅L–1) treatments alone or combination for 30 days, respectively. The bacterial community and antibiotic resistance genes (ARGs) of the treated sediments were analyzed by Illumina sequencing and metagenomic sequencing. Studies had shown that: TC, g-C3N4, and TC/g-C3N4 have significant effects on the changes of microbial communities and components in riverbed sediment, but they do not exist in pig farm sediment. The most alterations of microbial taxa were Acidobacteriota, Actinobacteriota, and Desulfobacterota in riverbed sediment, and Elusimicrobiota in the pig farm sediment under various treatments. Through network analysis, it was found that the distribution of microorganisms in the pig farm sediment is more complex and more stable. The addition of g-C3N4 reduced the absolute abundance of ARGs in the two examined sediments, but not significantly changed their relative abundance of ARGs. The g-C3N4 application was beneficial to the removal of TC residues and to the prevention of the generation and transmission of ARGs in sediments. Our results suggested that g-C3N4 was a suitable photocatalyst with excellent application prospect for the removal of TC residues and the control of ARGs in environment.</p