197 research outputs found
Three planets around HD 27894. A close-in pair with a 2:1 period ratio and an eccentric Jovian planet at 5.4 AU
Aims. Our new program with HARPS aims to detect mean motion resonant
planetary systems around stars which were previously reported to have a single
bona fide planet, often based only on sparse radial velocity data. Methods.
Archival and new HARPS radial velocities for the K2V star HD 27894 were
combined and fitted with a three-planet self-consistent dynamical model. The
best-fit orbit was tested for long-term stability. Results. We find clear
evidence that HD 27894 is hosting at least three massive planets. In addition
to the already known Jovian planet with a period 18 days
we discover a Saturn-mass planet with 36 days, likely in
a 2:1 mean motion resonance with the first planet, and a cold massive planet
( 5.3 ) with a period 5170
days on a moderately eccentric orbit ( = 0.39). Conclusions. HD
27894 is hosting a massive, eccentric giant planet orbiting around a tightly
packed inner pair of massive planets likely involved in an asymmetric 2:1 mean
motion resonance. HD 27894 may be an important milestone for probing planetary
formation and evolution scenarios.Comment: 4 pages, 2 tables, 3 figures. Accepted for publication in A&A Letters
to the Edito
Rossiter-McLaughlin Observations of 55 Cnc e
We present Rossiter-McLaughlin observations of the transiting super-Earth 55
Cnc e collected during six transit events between January 2012 and November
2013 with HARPS and HARPS-N. We detect no radial-velocity signal above 35 cm/s
(3-sigma) and confine the stellar v sin i to 0.2 +/- 0.5 km/s. The star appears
to be a very slow rotator, producing a very low amplitude Rossiter-McLaughlin
effect. Given such a low amplitude, the Rossiter-McLaughlin effect of 55 Cnc e
is undetected in our data, and any spin-orbit angle of the system remains
possible. We also performed Doppler tomography and reach a similar conclusion.
Our results offer a glimpse of the capacity of future instrumentation to study
low amplitude Rossiter-McLaughlin effects produced by super-Earths.Comment: Accepted for publication in ApJ Letter
The EBLM project. II. A very hot, low-mass M dwarf in an eccentric and long period eclipsing binary system from SuperWASP
In this paper, we derive the fundamental properties of
1SWASPJ011351.29+314909.7 (J0113+31), a metal-poor (-0.40 +/- 0.04 dex),
eclipsing binary in an eccentric orbit (~0.3) with an orbital period of ~14.277
d. Eclipsing M dwarfs orbiting solar-type stars (EBLMs), like J0113+31, have
been identified from WASP light curves and follow-up spectroscopy in the course
of the transiting planet search. We present the first binary of the EBLM sample
to be fully analysed, and thus, define here the methodology. The primary
component with a mass of 0.945 +/- 0.045 Msun has a large radius (1.378 +/-
0.058 Rsun) indicating that the system is quite old, ~9.5 Gyr. The M-dwarf
secondary mass of 0.186 +/- 0.010 Msun and radius of 0.209 +/- 0.011 Rsun are
fully consistent with stellar evolutionary models. However, from the
near-infrared secondary eclipse light curve, the M dwarf is found to have an
effective temperature of 3922 +/- 42 K, which is ~600 K hotter than predicted
by theoretical models. We discuss different scenarios to explain this
temperature discrepancy. The case of J0113+31 for which we can measure mass,
radius, temperature and metallicity, highlights the importance of deriving
mass, radius and temperature as a function of metallicity for M dwarfs to
better understand the lowest mass stars. The EBLM Project will define the
relationship between mass, radius, temperature and metallicity for M dwarfs
providing important empirical constraints at the bottom of the main sequence.Comment: 13 pages, 7 figures. Accepted for publication in A&
18F-PSMA-1007 PET/CT for response assessment in patients with metastatic renal cell carcinoma undergoing tyrosine kinase or checkpoint inhibitor therapy: preliminary results
INTRODUCTION Tyrosine kinase (TKI) and checkpoint inhibitors (CI) prolonged overall survival in metastatic renal cell carcinoma (mRCC). Early prediction of treatment response is highly desirable for the individualization of patient management and improvement of therapeutic outcome; however, serum biochemistry is unable to predict therapeutic efficacy. Therefore, we compared 18F-PSMA-1007 PET imaging for response assessment in mRCC patients undergoing TKI or CI therapy compared to CT-based response assessment as the current imaging reference standard.
METHODS 18F-PSMA-1007 PET/CT was performed in mRCC patients prior to initiation of systemic treatment and 8~weeks after therapy initiation. Treatment response was evaluated separately on 18F-PSMA-PET and CT. Changes on PSMA-PET (SUVmean) were assessed on a per patient basis using a modified PERCIST scoring system. Complete response (CRPET) was defined as absence of any uptake in all target lesions on posttreatment PET. Partial response (PRPET) was defined as decrease in summed SUVmean of > 30%. The appearance of new, PET-positive lesions or an increase in summed SUVmean of > 30% was defined as progressive disease (PDPET). A change in summed SUVmean of ± 30% defined stable disease (SDPET). RECIST 1.1 criteria were used for response assessment on CT. Results of radiographic response assessment on PSMA-PET and CT were compared.
RESULTS Overall, 11 mRCC patients undergoing systemic treatment were included. At baseline PSMA-PET1, all mRCC patients showed at least one PSMA-avid lesion. On follow-up PET2, 3 patients showed CRPET, 3 PRPET, 4 SDPET, and 1 PDPET. According to RECIST 1.1, 1 patient showed PRCT, 9 SDCT, and 1 PDCT. Overall, concordant classifications were found in only 2 cases (2 SDCT + PET). Patients with CRPET on PET were classified as 3 SDCT on CT using RECIST 1.1. By contrast, the patient classified as PRCT on CT showed PSMA uptake without major changes during therapy (SDPET). However, among 9 patients with SDCT on CT, 3 were classified as CRPET, 3 as PRPET, 1 as PDPET, and only 2 as SDPET on PSMA-PET. CONCLUSION On PSMA-PET, heterogeneous courses were observed during systemic treatment in mRCC patients with highly diverging results compared to RECIST 1.1. In the light of missing biomarkers for early response assessment, PSMA-PET might allow more precise response assessment to systemic treatment, especially in patients classified as SD on CT
Intermediate Resolution Near-Infrared Spectroscopy of 36 late-M Dwarfs
We present observations of 36 late-M dwarfs obtained with the KeckII/NIRSPEC
in the J-band at a resolution of \sim20,000. We have measured projected
rotational velocities, absolute radial velocities, and pseudo-equivalent widths
of atomic lines. 12 of our targets did not have previous measurements in the
literature.
For the other 24 targets, we confirm previously reported measurements. We
find that 13 stars from our sample have vsini below our measurement threshold
(12 km/s) whereas four of our targets are fast rotators (vsini > 30 km/s). As
fast rotation causes spectral features to be washed out, stars with low
projected rotational velocities are sought for radial velocity surveys.
At our intermediate spectral resolution we have confirmed the identification
of neutral atomic lines reported in Mclean et al. 2007. We also calculated
pseudo-equivalent widths (p-EW) of 12 atomic lines. Our results confirm that
the p-EW of K I lines are strongly dependent on spectral types. We observe that
the p-EW of Fe I and Mn I lines remain fairly constant with later spectral
type. We suggest that those lines are particularly suitable for deriving
metallicities for late-M dwarfs.Comment: accepted in Astronomical Journal. 30 pages, 7 tables, and 7 figure
A Spectral Survey of WASP-19b with ESPRESSO
High resolution precision spectroscopy provides a multitude of robust
techniques for probing exoplanetary atmospheres. We present multiple
VLT/ESPRESSO transit observations of the hot-Jupiter exoplanet WASP-19b with
previously published but disputed atmospheric features from low resolution
studies. Through spectral synthesis and modeling of the Rossiter-McLaughlin
(RM) effect we calculate stellar, orbital and physical parameters for the
system. From narrow-band spectroscopy we do not detect any of H\,I, Fe\,I,
Mg\,I, Ca\,I, Na\,I and K\,I neutral species, placing upper limits on their
line contrasts. Through cross correlation analyses with atmospheric models, we
do not detect Fe\,I and place a 3 upper limit of
on its mass
fraction, from injection and retrieval. We show the inability to detect the
presence of HO for known abundances, owing to lack of strong absorption
bands, as well as relatively low S/N ratio. We detect a barely significant peak
(3.02\,\,0.15\,) in the cross correlation map for TiO, consistent
with the sub-solar abundance previously reported. This is merely a hint for the
presence of TiO and does \textit{not} constitute a confirmation. However, we do
confirm the presence of previously observed enhanced scattering towards blue
wavelengths, through chromatic RM measurements, pointing to a hazy atmosphere.
We finally present a reanalysis of low resolution transmission spectra of this
exoplanet, concluding that unocculted starspots alone cannot explain previously
detected features. Our reanalysis of the FORS2 spectra of WASP-19b finds a
\,100 sub-solar TiO abundance, precisely constrained to
, consistent with the TiO hint
from ESPRESSO. We present plausible paths to reconciliation with other
seemingly contradicting results.Comment: 24 pages, 16 figures, submitted to MNRA
III.7 Planets orbiting stars more massive than the Sun
This book is dedicated to all the people interested in the CoRoT mission and the beautiful data that were delivered during its six year duration. Either amateurs, professional, young or senior researchers, they will find treasures not only at the time of this publication but also in the future twenty or thirty years. It presents the data in their final version, explains how they have been obtained, how to handle them, describes the tools necessary to understand them, and where to find them. It also highlights the most striking first results obtained up to now. CoRoT has opened several unexpected directions of research and certainly new ones still to be discovered
ROPS: A New Search for Habitable Earths in the Southern Sky
We present the first results from our Red Optical Planet Survey (ROPS) to
search for low mass planets orbiting late type dwarfs (M5.5V - M9V) in their
habitable zones (HZ). Our observations, with the red arm of the MIKE
spectrograph (0.5 - 0.9 microns) at the 6.5 m Magellan Clay telescope at Las
Campanas Observatory indicate that >= 92 per cent of the flux lies beyond 0.7
microns. We use a novel approach that is essentially a hybrid of the
simultaneous iodine and ThAr methods for determining precision radial
velocities. We apply least squares deconvolution to obtain a single high S/N
ratio stellar line for each spectrum and cross correlate against the
simultaneously observed telluric line profile, which we derive in the same way.
Utilising the 0.62 - 0.90 micron region, we have achieved an r.m.s. precision
of 10 m/s for an M5.5V spectral type star with spectral S/N ~160 on 5 minute
timescales. By M8V spectral type, a precision of ~30 m/s at S/N = 25 is
suggested, although more observations are needed. An assessment of our errors
and scatter in the radial velocity points hints at the presence of stellar
radial velocity variations. Of our sample of 7 stars, 2 show radial velocity
signals at 6-sigma and 10-sigma of the cross correlation uncertainties. If the
signals are planetary in origin, our findings are consistent with estimates of
Neptune mass planets that predict a frequency of 13 - 27 per cent for early M
dwarfs.Our current analysis indicates the we can achieve a sensitivity that is
equivalent to the amplitude induced by a 6 M_Earth planet orbiting in the
habitable zone. Based on simulations, we estimate that <10 M_Earth habitable
zone planets will be detected in a new stellar mass regime, with <=20 epochs of
observations.Comment: MNRAS accepted: 14 pages, 8 figures, 3 table
Evaluation of Hungarian Wines for Resveratrol by Overpressured Layer Chromatography
A method, including solid phase extraction sample preparation, overpressured layer chromatographic separation and subsequent densitometric evaluation, was developed for measurement of total resveratrol (cis- and trans-isomers) content of wine. The amount of resveratrol was determined in wine samples from different winemaking regions of Hungary. The total resveratrol was high in Hungarian red wines (3.6–11 mg/L), and much lower in white ones (0.04–1.5 mg/L)
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