138 research outputs found
Spin-Orbit Alignment of the TrES-4 Transiting Planetary System and Possible Additional Radial Velocity Variation
We report new radial velocities of the TrES-4 transiting planetary system,
including observations of a full transit, with the High Dispersion Spectrograph
of the Subaru 8.2m telescope. Modeling of the Rossiter-McLaughlin effect
indicates that TrES-4b has closely aligned orbital and stellar spin axes, with
. The close spin-orbit alignment angle
of TrES-4b seems to argue against a migration history involving planet-planet
scattering or Kozai cycles, although there are two nearby faint stars that
could be binary companion candidates. Comparison of our out-of-transit data
from 4 different runs suggest that the star exhibits radial velocity
variability of 20 ms^-1 in excess of a single Keplerian orbit. Although
the cause of the excess radial velocity variability is unknown, we discuss
various possibilities including systematic measurement errors, starspots or
other intrinsic motions, and additional companions besides the transiting
planet.Comment: 10 pages, 3 figures, 3 tables, PASJ in pres
Subaru HDS Transmission Spectroscopy of the Transiting Extrasolar Planet HD 209458b
We have searched for absorption in several common atomic species due to the
atmosphere or exosphere of the transiting extrasolar planet HD 209458b, using
high precision optical spectra obtained with the Subaru High Dispersion
Spectrograph (HDS). Previously we reported an upper limit on H alpha absorption
of 0.1% (3 sigma) within a 5.1\AA band. Using the same procedure, we now report
upper limits on absorption due to the optical transitions of Na D, Li, H alpha,
H beta, H gamma, Fe, and Ca. The 3 sigma upper limit for each transition is
approximately 1% within a 0.3\AA band (the core of the line), and a few tenths
of a per cent within a 2\AA band (the full line width). The wide-band results
are close to the expected limit due to photon-counting (Poisson) statistics,
although in the narrow-band case we have encountered unexplained systematic
errors at a few times the Poisson level. These results are consistent with all
previously reported detections and upper limits, but are significantly more
sensitive.Comment: 10 pages, 9 figure
Measurement of the Rossiter--McLaughlin Effect in the Transiting Exoplanetary System TrES-1
We report a measurement of the Rossiter--McLaughlin effect in the transiting
extrasolar planetary system TrES-1, via simultaneous spectroscopic and
photometric observations with the Subaru and MAGNUM telescopes. By modeling the
radial velocity anomaly that was observed during a transit, we determine the
sky-projected angle between the stellar spin axis and the planetary orbital
axis to be [deg]. This is the third case for which
has been measured in a transiting exoplanetary system, and the first
demonstration that such measurements are possible for relatively faint host
stars (, as compared to for the other systems). We also
derive a time of mid-transit, constraints on the eccentricity of the TrES-1b
orbit (), and upper limits on the mass of the Trojan
companions (14 ) at the 3 level.Comment: 8 pages, 5 figures, 2 tables. Published in PASJ. Corrected typo
Disks around massive young stellar objects: are they common?
We present K-band polarimetric images of several massive young stellar
objects at resolutions 0.1-0.5 arcsec. The polarization vectors around
these sources are nearly centro-symmetric, indicating they are dominating the
illumination of each field. Three out of the four sources show elongated
low-polarization structures passing through the centers, suggesting the
presence of polarization disks. These structures and their surrounding
reflection nebulae make up bipolar outflow/disk systems, supporting the
collapse/accretion scenario as their low-mass siblings. In particular, S140
IRS1 show well defined outflow cavity walls and a polarization disk which
matches the direction of previously observed equatorial disk wind, thus
confirming the polarization disk is actually the circumstellar disk. To date, a
dozen massive protostellar objects show evidence for the existence of disks;
our work add additional samples around MYSOs equivalent to early B-type stars.Comment: 9 pages, including 2 figures, 1 table, to appear on ApJ
Long-term prevention of renal insufficiency, excess matrix gene expression, and glomerular mesangial matrix expansion by treatment with monoclonal antitransforming growth factor-ß antibody in \u3ci\u3edb/db\u3c/i\u3e diabetic mice
Emerging evidence suggests that transforming growth factor-(TGF-β) is an important mediator of diabetic nephropathy. We showed previously that short-term treatment with a neutralizing monoclonal anti-TGF-antibody (αT) in streptozotocin-diabetic mice prevents early changes of renal hypertrophy and increased matrix mRNA. To establish that overactivity of the renal TGF-system mediates the functional and structural changes of the more advanced stages of nephropathy, we tested whether chronic administration of αT prevents renal insufficiency and glomerulosclerosis in the db/db mouse, model of type 2 diabetes that develops overt nephropathy. Diabetic db/db mice and nondiabetic db/m littermates were treated intraperitoneally with α or control IgG, 300 µg three times per week for 8 wk. Treatment with αT, but not with IgG, significantly decreased the plasma TGF-β1 concentration without decreasing the plasma glucose concentration. The IgG-treated db/db mice developed albuminuria, renal insufficiency, and glomerular mesangial matrix expansion associated with increased renal mRNAs encoding α 1(IV) collagen and fibronectin. On the other hand, treatment with α completely prevented the increase in plasma creatinine concentration, the decrease in urinary creatinine clearance, and the expansion of mesangial matrix in db/db mice. The increase in renal matrix mRNAs was substantially attenuated, but the excretion of urinary albumin factored for creatinine clearance was not significantly affected by α treatment. We conclude that chronic inhibition of the biologic actions of TGF-with neutralizing monoclonal antibody in db/db mice prevents the glomerulosclerosis and renal insufficiency resulting from type diabetes
Further Observations of the Tilted Planet XO-3: A New Determination of Spin-Orbit Misalignment, and Limits on Differential Rotation
Abstract: We report on observations of the Rossiter-McLaughlin (RM) effect for the XO-3 exoplanetary system. The RM effect for the system was previously measured by two different groups, but their results were statistically inconsistent. To obtain a decisive result we observed two full transits of XO-3b with the Subaru 8.2-m telescope. By modeling these data with a new and more accurate analytic formula for the RM effect, we find the projected spin-orbit angle to be λ=37.3 deg ± 3.0 deg, in good agreement with the previous finding by Winn et al. (2009). In addition, an offset of ~22 m/s[superscript -1] was observed between the two transit datasets. This offset could be a signal of a third body in the XO-3 system, a possibility that should be checked with future observations. We also attempt to search for a possible signature of the stellar differential rotation in the RM data for the first time, and put weak upper limits on the differential rotation parameters.United States. National Aeronautics and Space Administration (NNX11AG85G
Data Reduction Pipeline for the CHARIS Integral-Field Spectrograph I: Detector Readout Calibration and Data Cube Extraction
We present the data reduction pipeline for CHARIS, a high-contrast
integral-field spectrograph for the Subaru Telescope. The pipeline constructs a
ramp from the raw reads using the measured nonlinear pixel response, and
reconstructs the data cube using one of three extraction algorithms: aperture
photometry, optimal extraction, or fitting. We measure and apply both
a detector flatfield and a lenslet flatfield and reconstruct the wavelength-
and position-dependent lenslet point-spread function (PSF) from images taken
with a tunable laser. We use these measured PSFs to implement a -based
extraction of the data cube, with typical residuals of ~5% due to imperfect
models of the undersampled lenslet PSFs. The full two-dimensional residual of
the extraction allows us to model and remove correlated read noise,
dramatically improving CHARIS' performance. The extraction produces a
data cube that has been deconvolved with the line-spread function, and never
performs any interpolations of either the data or the individual lenslet
spectra. The extracted data cube also includes uncertainties for each spatial
and spectral measurement. CHARIS' software is parallelized, written in Python
and Cython, and freely available on github with a separate documentation page.
Astrometric and spectrophotometric calibrations of the data cubes and PSF
subtraction will be treated in a forthcoming paper.Comment: 18 pages, 15 figures, 3 tables, replaced with JATIS accepted version
(emulateapj formatted here). Software at
https://github.com/PrincetonUniversity/charis-dep and documentation at
http://princetonuniversity.github.io/charis-de
Improved Measurement of the Rossiter-McLaughlin Effect in the Exoplanetary System HD 17156
We present an improved measurement of the Rossiter-McLaughlin effect for the
exoplanetary system HD 17156, based on radial-velocity data gathered with the
Subaru 8.2m telescope throughout the planetary transit of UT 2008 November 7.
The data allow for a precise and independent determination of the projected
spin-orbit angle of this system: . This
result supersedes the previous claim of
by Narita et al., which was based on lower-precision data with poor statistics.
Thus the stellar spin and planetary orbital axes of the HD 17156 system are
likely to be well-aligned, despite the planet's large orbital eccentricity
suggesting a history of strong dynamical interactions.Comment: 16 pages, 3 figures, 3 tables, PASJ accepte
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