353 research outputs found
Comic Books vs. Greek Mythology: the Ultimate Crossover for the Classical Scholar
The modern, serialized comic book is one of the most underutilized genres of literature in literary criticism today. While it is true that some graphic novels such as Alan Moore\u27s Watchmen and Frank Miller\u27s The Dark Knight Returns receive scholarly criticism, many monthly titles such as Action Comics or Batman are neglected by most of the scholarly community. The reason for this neglect cannot be traced to one single source, but it is unfortunate considering how valuable serialized comic books can be to modern scholars, particularly classical scholars studying Greek mythology. The similarities between the superheroes of serialized comic books and the heroes of Greek mythology result in an interesting genre of literature that can allow classical scholars to observe how modern writers reinterpret the classical texts of Greek mythology. It is the purpose of this thesis to examine various intersecting similarities between mythological heroes and modern superheroes in the hopes of encouraging further discussion of modern serialized comic books in the scholarly world
Multiwavelength transit observations of the candidate disintegrating planetesimals orbiting WD 1145+017
We present multiwavelength, ground-based follow-up photometry of the white dwarf WD 1145+017, which has recently been suggested to be orbited by up to six or more short-period, low-mass, disintegrating planetesimals. We detect nine significant dips in flux of between 10% and 30% of the stellar flux in our ~32 hr of photometry, suggesting that WD 1145+017 is indeed being orbited by multiple, short-period objects. Through fits to the asymmetric transits that we observe, we confirm that the transit egress is usually longer than the ingress, and that the transit duration is longer than expected for a solid body at these short periods, all suggesting that these objects have cometary tails streaming behind them. The precise orbital periods of the planetesimals are unclear, but at least one object, and likely more, have orbital periods of ~4.5 hr. We are otherwise unable to confirm the specific periods that have been reported, bringing into question the long-term stability of these periods. Our high-precision photometry also displays low-amplitude variations, suggesting that dusty material is consistently passing in front of the white dwarf, either from discarded material from these disintegrating planetesimals or from the detected dusty debris disk. We compare the transit depths in the V- and R-bands of our multiwavelength photometry, and find no significant difference; therefore, for likely compositions, the radius of single-size particles in the cometary tails streaming behind the planetesimals must be ~0.15 μm or larger, or ~0.06 μm or smaller, with 2σ confidence
Multiwavelength Transit Observations of the Candidate Disintegrating Planetesimals Orbiting WD 1145+017
We present multiwavelength, multi-telescope, ground-based follow-up
photometry of the white dwarf WD 1145+017, that has recently been suggested to
be orbited by up to six or more, short-period, low-mass, disintegrating
planetesimals. We detect 9 significant dips in flux of between 10% and 30% of
the stellar flux from our ground-based photometry. We observe transits deeper
than 10% on average every ~3.6 hr in our photometry. This suggests that WD
1145+017 is indeed being orbited by multiple, short-period objects. Through
fits to the multiple asymmetric transits that we observe, we confirm that the
transit egress timescale is usually longer than the ingress timescale, and that
the transit duration is longer than expected for a solid body at these short
periods, all suggesting that these objects have cometary tails streaming behind
them. The precise orbital periods of the planetesimals in this system are
unclear from the transit-times, but at least one object, and likely more, have
orbital periods of ~4.5 hours. We are otherwise unable to confirm the specific
periods that have been reported, bringing into question the long-term stability
of these periods. Our high precision photometry also displays low amplitude
variations suggesting that dusty material is consistently passing in front of
the white dwarf, either from discarded material from these disintegrating
planetesimals or from the detected dusty debris disk. For the significant
transits we observe, we compare the transit depths in the V- and R-bands of our
multiwavelength photometry, and find no significant difference; therefore, for
likely compositions the radius of single-size particles in the cometary tails
streaming behind the planetesimals in this system must be ~0.15 microns or
larger, or ~0.06 microns or smaller, with 2-sigma confidence.Comment: 16 pages, 12 figures, submitted to ApJ on October 8th, 201
The Kepler-10 planetary system revisited by HARPS-N: A hot rocky world and a solid Neptune-mass planet
Kepler-10b was the first rocky planet detected by the Kepler satellite and
con- firmed with radial velocity follow-up observations from Keck-HIRES. The
mass of the planet was measured with a precision of around 30%, which was
insufficient to constrain models of its internal structure and composition in
detail. In addition to Kepler-10b, a second planet transiting the same star
with a period of 45 days was sta- tistically validated, but the radial
velocities were only good enough to set an upper limit of 20 Mearth for the
mass of Kepler-10c. To improve the precision on the mass for planet b, the
HARPS-N Collaboration decided to observe Kepler-10 intensively with the HARPS-N
spectrograph on the Telescopio Nazionale Galileo on La Palma. In to- tal, 148
high-quality radial-velocity measurements were obtained over two observing
seasons. These new data allow us to improve the precision of the mass
determina- tion for Kepler-10b to 15%. With a mass of 3.33 +/- 0.49 Mearth and
an updated radius of 1.47 +0.03 -0.02 Rearth, Kepler-10b has a density of 5.8
+/- 0.8 g cm-3, very close to the value -0.02 predicted by models with the same
internal structure and composition as the Earth. We were also able to determine
a mass for the 45-day period planet Kepler-10c, with an even better precision
of 11%. With a mass of 17.2 +/- 1.9 Mearth and radius of 2.35 +0.09 -0.04
Rearth, -0.04 Kepler-10c has a density of 7.1 +/- 1.0 g cm-3. Kepler-10c
appears to be the first strong evidence of a class of more massive solid
planets with longer orbital periods.Comment: 44 pages, 8 figures, accepted for publication in Ap
A thin layer angiogenesis assay: a modified basement matrix assay for assessment of endothelial cell differentiation
BACKGROUND: Basement matrices such as Matrigel™ and Geltrex™ are used in a variety of cell culture assays of anchorage-dependent differentiation including endothelial cell tube formation assays. The volumes of matrix recommended for these assays (approximately 150 μl/cm(2)) are costly, limit working distances for microscopy, and require cell detachment for subsequent molecular analysis. Here we describe the development and validation of a thin-layer angiogenesis (TLA) assay for assessing the angiogenic potential of endothelial cells that overcomes these limitations. RESULTS: Geltrex™ basement matrix at 5 μl/cm(2) in 24-well (10 μl) or 96-well (2 μl) plates supports endothelial cell differentiation into tube-like structures in a comparable manner to the standard larger volumes of matrix. Since working distances are reduced, high-resolution single cell microscopy, including DIC and confocal imaging, can be used readily. Using MitoTracker dye we now demonstrate, for the first time, live mitochondrial dynamics and visualise the 3-dimensional network of mitochondria present in differentiated endothelial cells. Using a standard commercial total RNA extraction kit (Qiagen) we also show direct RNA extraction and RT-qPCR from differentiated endothelial cells without the need to initially detach cells from their supporting matrix. CONCLUSIONS: We present here a new thin-layer assay (TLA) for measuring the anchorage-dependent differentiation of endothelial cells into tube-like structures which retains all the characteristics of the traditional approach but with the added benefit of a greatly lowered cost and better compatibility with other techniques, including RT-qPCR and high-resolution microscopy. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (doi:10.1186/s12860-014-0041-5) contains supplementary material, which is available to authorized users
Discovery of a massive giant planet with extreme density around a sub-giant star TOI-4603
We present the discovery of a transiting massive giant planet around
TOI-4603, a sub-giant F-type star from NASA's Transiting Exoplanet Survey
Satellite (TESS). The newly discovered planet has a radius of
, and an orbital period of
days. Using radial velocity measurements with
the PARAS {and TRES} spectrographs, we determined the planet's mass to be
, resulting in a bulk density of
g . This makes it one of the few massive giant
planets with extreme density and lies in the transition mass region of massive
giant planets and low-mass brown dwarfs, an important addition to the
population of less than five objects in this mass range. The eccentricity of
and an orbital separation of AU from its host
star suggest that the planet is likely undergoing high eccentricity tidal (HET)
migration. We find a fraction of heavy elements of and
metal enrichment of the planet () of .
Detection of such systems will offer us to gain valuable insights into the
governing mechanisms of massive planets and improve our understanding of their
dominant formation and migration mechanisms.Comment: accepted for publication in A&A Letter
The Revised TESS Input Catalog and Candidate Target List
We describe the catalogs assembled and the algorithms used to populate the
revised TESS Input Catalog (TIC), based on the incorporation of the Gaia second
data release. We also describe a revised ranking system for prioritizing stars
for 2-minute cadence observations, and assemble a revised Candidate Target List
(CTL) using that ranking. The TIC is available on the Mikulski Archive for
Space Telescopes (MAST) server, and an enhanced CTL is available through the
Filtergraph data visualization portal system at the URL
http://filtergraph.vanderbilt.edu/tess_ctl.Comment: 30 pages, 16 figures, submitted to AAS Journals; provided to the
community in advance of publication in conjunction with public release of the
TIC/CTL on 28 May 201
Near Infrared Monitoring of Ultracool Dwarfs: Prospects for Searching for Transiting Companions
Stars of late-M and L spectral types, collectively known as Ultracool Dwarfs
(UCDs), may be excellent targets for searches for extrasolar planets. Owing to
their small radii, the signal from an Earth-size planet transiting a UCD is, in
principle, readily detectable. We present results from a study designed to
evaluate the feasibility of using precise near infrared (NIR) photometry to
detect terrestrial extrasolar planets orbiting UCDs. We used the Peters
Automated InfRared Imaging TELescope (PAIRITEL) to observe a sample of 13 UCDs
over a period of 10 months. We consider several important systematic effects in
NIR differential photometry and develop techniques for generating photometry
with a precision of 0.01 mag and long-term stability. We simulate the planet
detection efficiency of an extended campaign to monitor a large sample of UCDs
with PAIRITEL. We find that both a targeted campaign with a single telescope
lasting several years and a campaign making use of a network of telescopes
distributed in longitude could provide significant sensitivity to terrestrial
planets orbiting UCDs, potentially in the habitable zone.Comment: 22 pages, 5 figures, 3 tables. Accepted for publication in PAS
Multiwavelength Transit Observations of the Candidate Disintegrating Planetesimals Orbiting WD 1145+017
We present multiwavelength, ground-based follow-up photometry of the white dwarf WD 1145+017, which has recently been suggested to be orbited by up to six or more short-period, low-mass, disintegrating planetesimals. We detect nine significant dips in flux of between 10% and 30% of the stellar flux in our ~32 hr of photometry, suggesting that WD 1145+017 is indeed being orbited by multiple, short-period objects. Through fits to the asymmetric transits that we observe, we confirm that the transit egress is usually longer than the ingress, and that the transit duration is longer than expected for a solid body at these short periods, all suggesting that these objects have cometary tails streaming behind them. The precise orbital periods of the planetesimals are unclear, but at least one object, and likely more, have orbital periods of ~4.5 hr. We are otherwise unable to confirm the specific periods that have been reported, bringing into question the long-term stability of these periods. Our high-precision photometry also displays low-amplitude variations, suggesting that dusty material is consistently passing in front of the white dwarf, either from discarded material from these disintegrating planetesimals or from the detected dusty debris disk. We compare the transit depths in the V- and R-bands of our multiwavelength photometry, and find no significant difference; therefore, for likely compositions, the radius of single-size particles in the cometary tails streaming behind the planetesimals must be ~0.15 μm or larger, or ~0.06 μm or smaller, with 2σ confidence
GJ 3236: a new bright, very low-mass eclipsing binary system discovered by the MEarth observatory
We report the detection of eclipses in GJ 3236, a bright (I = 11.6) very low
mass binary system with an orbital period of 0.77 days. Analysis of light- and
radial velocity curves of the system yielded component masses of 0.38 +/- 0.02
and 0.28 +/- 0.02 Msol. The central values for the stellar radii are larger
than the theoretical models predict for these masses, in agreement with the
results for existing eclipsing binaries, although the present 5% observational
uncertainties limit the significance of the larger radii to approximately 1
sigma. Degeneracies in the light curve models resulting from the unknown
configuration of surface spots on the components of GJ 3236 currently dominate
the uncertainties in the radii, and could be reduced by obtaining precise,
multi-band photometry covering the full orbital period. The system appears to
be tidally synchronized and shows signs of high activity levels as expected for
such a short orbital period, evidenced by strong Halpha emission lines in the
spectra of both components. These observations probe an important region of
mass-radius parameter space around the predicted transition to fully-convective
stellar interiors, where there are a limited number of precise measurements
available in the literature.Comment: 14 pages, 5 figures, 10 tables, emulateapj format. Accepted for
publication in Ap
- …