826 research outputs found
Searching for young Jupiter analogs around AP Col: L-band high-contrast imaging of the closest pre-main sequence star
The nearby M-dwarf AP Col was recently identified by Riedel et al. 2011 as a
pre-main sequence star (age 12 - 50 Myr) situated only 8.4 pc from the Sun. The
combination of its youth, distance, and intrinsically low luminosity make it an
ideal target to search for extrasolar planets using direct imaging. We report
deep adaptive optics observations of AP Col taken with VLT/NACO and Keck/NIRC2
in the L-band. Using aggressive speckle suppression and background subtraction
techniques, we are able to rule out companions with mass m >= 0.5 - 1M_Jup for
projected separations a>4.5 AU, and m >= 2 M_Jup for projected separations as
small as 3 AU, assuming an age of 40 Myr using the COND theoretical
evolutionary models. Using a different set of models the mass limits increase
by a factor of ~2. The observations presented here are the deepest
mass-sensitivity limits yet achieved within 20 AU on a star with direct
imaging. While Doppler radial velocity surveys have shown that Jovian bodies
with close-in orbits are rare around M-dwarfs, gravitational microlensing
studies predict that ~17% of these stars host massive planets with orbital
separations of 1-10 AU. Sensitive high-contrast imaging observations, like
those presented here, will help to validate results from complementary
detection techniques by determining the frequency of gas giant planets on wide
orbits around M-dwarfs.Comment: Accepted for publication in ApJ, 6 pages text ApJ style (incl.
references), 4 figures, 1 tabl
Abuse of nutmeg seeds: Detectable by means of liquid chromatography-mass spectrometry techniques?
Numerous case reports of intoxications with nutmeg seeds (Myristica fragrans, Houtt.)
can be found in literature often following their abuse, as psychotropic effects were
described after ingestions of large doses. The successful detection of the main ingredients of the nutmeg seeds essential oil elemicin, myristicin, and safrole, as well as
their metabolites in human urine by gas chromatography coupled to mass spectrometry (GC-MS) was already described. The aim of this study was to investigate the
detectability of the main ingredients of nutmeg seeds and their metabolites in human
blood and urine samples using liquid chromatography coupled to linear ion trap mass
spectrometry (LC-LIT-MSn
) and liquid chromatography coupled to high-resolution
mass spectrometry (LC-HRMS/MS) after nutmeg seed abuse. Sample material of
three individuals was retrospectively investigated after a systematic screening
approach indicated an intoxication with nutmeg seeds as a likely cause of symptoms.
Metabolic patterns in plasma and urine using GC-MS were comparable with those
described in earlier publications. Investigations using hyphenated liquid chromatography techniques lead to the detection of myristicin and safrole, as well as further
metabolites not described using GC-MS and revealed sulfation as an additional Phase
II metabolic pathway. These results might help to detect or confirm future intoxications with nutmeg seeds by using LC-MS techniques
An apodizing phase plate coronagraph for VLT/NACO
We describe a coronagraphic optic for use with CONICA at the VLT that
provides suppression of diffraction from 1.8 to 7 lambda/D at 4.05 microns, an
optimal wavelength for direct imaging of cool extrasolar planets. The optic is
designed to provide 10 magnitudes of contrast at 0.2 arcseconds, over a
D-shaped region in the image plane, without the need for any focal plane
occulting mask.Comment: 9 pages, 5 figures, to appear in Proc. SPIE Vol. 773
Confirmation and characterization of the protoplanet HD100546 b - Direct evidence for gas giant planet formation at 50 au
We present the first multi-wavelength, high-contrast imaging study confirming
the protoplanet embedded in the disk around the Herbig Ae/Be star HD100546. The
object is detected at () and (),
but not at (), and the emission consists of a point
source component surrounded by spatially resolved emission. For the point
source component we derive apparent magnitudes of mag,
mag, and mag (3 limit), and a
separation and position angle of and ,
and and in and , respectively.
We demonstrate that the object is co-moving with HD100546 and can reject any
(sub-)stellar fore-/background object. Fitting a single temperature blackbody
to the observed fluxes of the point source component yields an effective
temperature of K and a radius for the emitting area
of R. The best-fit luminosity is
. We quantitatively compare
our findings with predictions from evolutionary and atmospheric models for
young, gas giant planets, discuss the possible existence of a warm,
circumplanetary disk, and note that the de-projected physical separation from
the host star of au poses a challenge standard planet formation
theories. Considering the suspected existence of an additional planet orbiting
at 13--14 au, HD100546 appears to be an unprecedented laboratory to study
the formation of multiple gas giant planets empirically.Comment: Accepted for publication in ApJ; 13 pages incl. 9 figures, 2 tables
and references in ApJ-styl
Constraints on the nearby exoplanet Eps Ind Ab from deep near/mid-infrared imaging limits
© ESO 2021. This is the accepted manuscript version of an article which has been published in final form at https://doi.org/10.1051/0004-6361/202140730The past decade has seen increasing efforts in detecting and characterising exoplanets by high contrast imaging in the near/mid-infrared, which is the optimal wavelength domain for studying old, cold planets. In this work, we present deep AO imaging observations of the nearby Sun-like star Ind A with NaCo () and NEAR (10-12.5 microns) instruments at VLT, in an attempt to directly detect its planetary companion whose presence has been indicated from radial velocity (RV) and astrometric trends. We derive brightness limits from the non-detection of the companion with both instruments, and interpret the corresponding sensitivity in mass based on both cloudy and cloud-free atmospheric and evolutionary models. For an assumed age of 5 Gyr for the system, we get detectable mass limits as low as 4.4 in NaCo and 8.2 in NEAR bands at 1.5\arcsec from the central star. If the age assumed is 1 Gyr, we reach even lower mass limits of 1.7 in NaCo and 3.5 in NEAR bands, at the same separation. However, based on the dynamical mass estimate (3.25 ) and ephemerides from astrometry and RV, we find that the non-detection of the planet in these observations puts a constraint of 2 Gyr on the lower age limit of the system. NaCo offers the highest sensitivity to the planetary companion in these observations, but the combination with the NEAR wavelength range adds a considerable degree of robustness against uncertainties in the atmospheric models. This underlines the benefits of including a broad set of wavelengths for detection and characterisation of exoplanets in direct imaging studies.Peer reviewe
Criteria for Reporting the Development and Evaluation of Complex Interventions in healthcare: revised guideline (CReDECI 2)
The JWST Early Release Science Program for Direct Observations of Exoplanetary Systems II: A 1 to 20 Micron Spectrum of the Planetary-Mass Companion VHS 1256-1257 b
We present the highest fidelity spectrum to date of a planetary-mass object.
VHS 1256 b is a 20 M widely separated (8\arcsec, a =
150 au), young, planetary-mass companion that shares photometric colors and
spectroscopic features with the directly imaged exoplanets HR 8799 c, d, and e.
As an L-to-T transition object, VHS 1256 b exists along the region of the
color-magnitude diagram where substellar atmospheres transition from cloudy to
clear. We observed VHS 1256~b with \textit{JWST}'s NIRSpec IFU and MIRI MRS
modes for coverage from 1 m to 20 m at resolutions of 1,000 -
3,700. Water, methane, carbon monoxide, carbon dioxide, sodium, and potassium
are observed in several portions of the \textit{JWST} spectrum based on
comparisons from template brown dwarf spectra, molecular opacities, and
atmospheric models. The spectral shape of VHS 1256 b is influenced by
disequilibrium chemistry and clouds. We directly detect silicate clouds, the
first such detection reported for a planetary-mass companion.Comment: Accepted ApJL Iterations of spectra reduced by the ERS team are
hosted at this link:
https://github.com/bemiles/JWST_VHS1256b_Reduction/tree/main/reduced_spectr
The JWST Early Release Science Program for Direct Observations of Exoplanetary Systems IV: NIRISS Aperture Masking Interferometry Performance and Lessons Learned
We present a performance analysis for the aperture masking interferometry
(AMI) mode on board the James Webb Space Telescope Near Infrared Imager and
Slitless Spectrograph (JWST/NIRISS). Thanks to self-calibrating observables,
AMI accesses inner working angles down to and even within the classical
diffraction limit. The scientific potential of this mode has recently been
demonstrated by the Early Release Science (ERS) 1386 program with a deep search
for close-in companions in the HIP 65426 exoplanetary system. As part of ERS
1386, we use the same dataset to explore the random, static, and calibration
errors of NIRISS AMI observables. We compare the observed noise properties and
achievable contrast to theoretical predictions. We explore possible sources of
calibration errors, and show that differences in charge migration between the
observations of HIP 65426 and point-spread function calibration stars can
account for the achieved contrast curves. Lastly, we use self-calibration tests
to demonstrate that with adequate calibration, NIRISS AMI can reach contrast
levels of mag. These tests lead us to observation planning
recommendations and strongly motivate future studies aimed at producing
sophisticated calibration strategies taking these systematic effects into
account. This will unlock the unprecedented capabilities of JWST/NIRISS AMI,
with sensitivity to significantly colder, lower mass exoplanets than
ground-based setups at orbital separations inaccessible to JWST coronagraphy.Comment: 20 pages, 12 figures, submitted to AAS Journal
The \textit{JWST} Early Release Science Program for Direct Observations of Exoplanetary Systems III: Aperture Masking Interferometric Observations of the star HIP\,65426 at
We present aperture masking interferometry (AMI) observations of the star HIP
65426 at as a part of the \textit{JWST} Direct Imaging Early
Release Science (ERS) program obtained using the Near Infrared Imager and
Slitless Spectrograph (NIRISS) instrument. This mode provides access to very
small inner working angles (even separations slightly below the Michelson limit
of for an interferometer), which are inaccessible with the
classical inner working angles of the \textit{JWST} coronagraphs. When combined
with \textit{JWST}'s unprecedented infrared sensitivity, this mode has the
potential to probe a new portion of parameter space across a wide array of
astronomical observations. Using this mode, we are able to achieve a contrast
of \,mag relative to the host star at a separation
of {\sim}0.07\arcsec but detect no additional companions interior to the
known companion HIP\,65426\,b. Our observations thus rule out companions more
massive than 10{-}12\,\rm{M\textsubscript{Jup}} at separations
from HIP\,65426, a region out of reach of ground or
space-based coronagraphic imaging. These observations confirm that the AMI mode
on \textit{JWST} is sensitive to planetary mass companions orbiting at the
water frost line, even for more distant stars at 100\,pc. This result
will allow the planning and successful execution of future observations to
probe the inner regions of nearby stellar systems, opening essentially
unexplored parameter space.Comment: 15 pages, 9 figures, submitted to ApJ Letter
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