646 research outputs found
Multi-band high resolution spectroscopy rules out the hot Jupiter BD+20 1790b - First data from the GIARPS Commissioning
Context. Stellar activity is currently challenging the detection of young
planets via the radial velocity (RV) technique. Aims. We attempt to
definitively discriminate the nature of the RV variations for the young active
K5 star BD+20 1790, for which visible (VIS) RV measurements show divergent
results on the existence of a substellar companion. Methods. We compare VIS
data with high precision RVs in the near infrared (NIR) range by using the
GIANO - B and IGRINS spectrographs. In addition, we present for the first time
simultaneous VIS-NIR observations obtained with GIARPS (GIANO - B and HARPS -
N) at Telescopio Nazionale Galileo (TNG). Orbital RVs are achromatic, so the RV
amplitude does not change at different wavelengths, while stellar activity
induces wavelength-dependent RV variations, which are significantly reduced in
the NIR range with respect to the VIS. Results. The NIR radial velocity
measurements from GIANO - B and IGRINS show an average amplitude of about one
quarter with respect to previously published VIS data, as expected when the RV
jitter is due to stellar activity. Coeval multi-band photometry surprisingly
shows larger amplitudes in the NIR range, explainable with a mixture of cool
and hot spots in the same active region. Conclusions. In this work, the claimed
massive planet around BD+20 1790 is ruled out by our data. We exploited the
crucial role of multi- wavelength spectroscopy when observing young active
stars: thanks to facilities like GIARPS that provide simultaneous observations,
this method can reach its maximum potential.Comment: 12 pages, 7 figure
The GAPS programme at TNG XXII. The GIARPS view of the extended helium atmosphere of HD189733 b accounting for stellar activity
Exoplanets orbiting very close to their host star are strongly irradiated.
This can lead the upper atmospheric layers to expand and evaporate into space.
The metastable helium (HeI) triplet at 1083.3nm has recently been shown to be a
powerful diagnostic to probe extended and escaping exoplanetary atmosphere. We
perform high-resolution transmission spectroscopy of the transiting hot Jupiter
HD189733b with the GIARPS (GIANO-B + HARPS-N) observing mode of the Telescopio
Nazionale Galileo, taking advantage of the simultaneous optical+near infrared
spectral coverage to detect HeI in the planet's extended atmosphere and to
gauge the impact of stellar magnetic activity on the planetary absorption
signal. Observations were performed during five transit events of HD189733b. By
comparison of the in- and out-of-transit GIANO-B observations we compute
high-resolution transmission spectra, on which we perform equivalent width
measurements and light-curves analyses to gauge the excess in-transit
absorption in the HeI triplet. We detect an absorption signal during all five
transits. The mean in-transit absorption depth amounts to 0.75+/-0.03%. We
detect night-to-night variations in the HeI absorption signal likely due to the
transit events occurring in presence of stellar surface inhomogeneities. We
evaluate the impact of stellar-activity pseudo-signals on the true planetary
absorption using a comparative analysis of the HeI and the H lines. We
interpret the time-series of the HeI absorption lines in the three nights not
affected by stellar contamination -exhibiting a mean in-transit absorption
depth of 0.77+/-0.04%- using a 3-d atmospheric code. Our simulations suggest
that the helium layers only fill part of the Roche lobe. Observations can be
explained with a thermosphere heated to 12000 K, expanding up to
1.2 planetary radii, and losing 1 g/s of metastable helium.Comment: 17 pages, 17 figures, accepted for publication in A&
Case report 511
Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/46790/1/256_2004_Article_BF00364055.pd
Case report 511
Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/46792/1/256_2004_Article_BF00366771.pd
GIARPS: commissioning and first scientific results
GIARPS (GIAno \& haRPS) is a project devoted to have on the same focal
station of the Telescopio Nazionale Galileo (TNG) both high resolution
spectrographs, HARPS-N (VIS) and GIANO-B (NIR), working simultaneously. This
could be considered the first and unique worldwide instrument providing
cross-dispersed echelle spectroscopy at a resolution of 50,000 in the NIR range
and 115,000 in the VIS and over in a wide spectral range (m)
in a single exposure. The science case is very broad, given the versatility of
such an instrument and its large wavelength range. A number of outstanding
science cases encompassing mainly extra-solar planet science starting from
rocky planets search and hot Jupiters to atmosphere characterization can be
considered. Furthermore both instruments can measure high precision radial
velocities by means the simultaneous thorium technique (HARPS-N) and absorbing
cell technique (GIANO-B) in a single exposure. Other science cases are also
possible. GIARPS, as a brand new observing mode of the TNG started after the
moving of GIANO-A (fiber fed spectrograph) from Nasmyth-A to Nasmyth-B where it
was re-born as GIANO-B (no more fiber feed spectrograph). The official
Commissioning finished on March 2017 and then it was offered to the community.
Despite the work is not finished yet. In this paper we describe the preliminary
scientific results obtained with GIANO-B and GIARPS observing mode with data
taken during commissioning and first open time observations.Comment: 10 pages, 11 figures, Telescopes and Astronomical instrumentation,
SPIE Conf. 201
Quantitative trait loci conferring grain mineral nutrient concentrations in durum wheat 3 wild emmer wheat RIL population
Mineral nutrient malnutrition, and particularly
deficiency in zinc and iron, afflicts over 3 billion people
worldwide. Wild emmer wheat, Triticum turgidum ssp.
dicoccoides, genepool harbors a rich allelic repertoire for
mineral nutrients in the grain. The genetic and physiological
basis of grain protein, micronutrients (zinc, iron,
copper and manganese) and macronutrients (calcium,
magnesium, potassium, phosphorus and sulfur) concentration
was studied in tetraploid wheat population of 152
recombinant inbred lines (RILs), derived from a cross
between durum wheat (cv. Langdon) and wild emmer
(accession G18-16). Wide genetic variation was found
among the RILs for all grain minerals, with considerable
transgressive effect. A total of 82 QTLs were mapped for
10 minerals with LOD score range of 3.2–16.7. Most QTLs
were in favor of the wild allele (50 QTLs). Fourteen pairs
of QTLs for the same trait were mapped to seemingly
homoeologous positions, reflecting synteny between the A
and B genomes. Significant positive correlation was found
between grain protein concentration (GPC), Zn, Fe and Cu,
which was supported by significant overlap between the
respective QTLs, suggesting common physiological and/or
genetic factors controlling the concentrations of these
mineral nutrients. Few genomic regions (chromosomes 2A,
5A, 6B and 7A) were found to harbor clusters of QTLs for
GPC and other nutrients. These identified QTLs may
facilitate the use of wild alleles for improving grain
nutritional quality of elite wheat cultivars, especially in
terms of protein, Zn and Fe
- …