Ripeness attributes of Arkansas-grown peaches and nectarines at harvest and during postharvest storage

Since peaches and nectarines are a valued fresh-market crop worldwide, evaluating postharvest potential helps determine feasibility for commercial markets. The ripeness attributes of 10 peach and nectarine genotypes were evaluated at harvest (day 0) and after 7 and 14 d storage at 4° C. The fruit was hand harvested at tree ripeness (ripened on the tree) and commercial ripeness (ripened during storage). The attributes of the tree-ripened fruit and commercially-ripened fruit varied at harvest and included chlorophyll (0.04-0.86 abs), peach weight (132-264 g), soluble solids (7.23-12.57%), pH (3.18-4.66), titratable acidity (0.16-1.21%), and flesh firmness (6.92-35.72 N). In general, tree-ripened fruit had higher fruit weight, soluble solids, and pH and lower chlorophyll, titratable acidity, and firmness than commercially-ripened fruit at harvest. For the tree-ripened fruit, A-811 CN was the largest (247.67 g), A-794 CN had the highest soluble solids (12.57%) and titratable acidity (0.88%), ‘Souvenirs’ (6.92 N) had the lowest firmness, and ‘Amoore Sweet’ (18.28 N) was the firmest. During storage of commercially-ripened fruit, chlorophyll and fruit weight decreased, while soluble solids increased, but there were no changes in pH or titratable acidity. During storage, A-885 (0.35 abs) had the lowest chlorophyll and ‘Effie’ had the largest fruit (203.11 g) and highest soluble solids (12.02%). Some ripeness attributes of the commercially-ripened fruit, such as chlorophyll and weight, were not achieved as compared to the tree-ripened fruit. The results of this study provide insight on the potential for releasing new peach and nectarine genotypes from the University of Arkansas Fruit Breeding Program

The Anomalous Infrared Emission of Abell 58

We present a new model to explain the excess in mid and near infrared emission of the central, hydrogen poor dust knot in the planetary nebula (PN) Abell 58. Current models disagree with ISO measurement because they apply an average grain size and equilibrium conditions only. We investigate grain size distributions and temperature fluctuations affecting infrared emission using a new radiative transfer code and discuss in detail the conditions requiring an extension of the classical description. The peculiar infrared emission of V605 Aql, the central dust knot in Abell 58, has been modeled with our code. V605 Aql is of special interest as it is one of only three stars ever observed to move from the evolutionary track of a central PN star back to the post-AGB state.Comment: 17 pages, 4 figures; accepted and to be published in Ap

Thermal infrared observations of near-Earth asteroid 2002 NY40

We obtained N-band observations of the Apollo asteroid 2002 NY40 during its close Earth fly-by in August 2002 with TIMMI2 at the ESO 3.6 m telescope. The photometric measurement allowed us to derive a radiometric diameter of 0.28+/-0.03 km and an albedo of 0.34+/-0.06 through the near-Earth asteroid thermal model (NEATM) and a thermophysical model (TPM). The values are in agreement with results from radar data, visual and near-IR observations. In this first comparison between these two model approaches we found that the empirical NEATM beaming parameter $\eta$=1.0 corresponds to a thermal inertia values of about 100 $\mathrm{J m^{-2} s^{-0.5} K^{-1}}$ for a typical range of surface roughness, assuming an equator-on viewing angle. Our TPM analysis indicated that the surface of 2002 NY40 consists of rocky material with a thin or no dust regolith. The asteroid very likely has a prograde sense of rotation with a cold terminator at the time of our observations. Although both model approaches can fit the thermal spectra taken at phase angles of 22$^{\circ}$ and 59$^{\circ}$, we did not find a consistent model solution that describes all pieces of photometric and spectroscopic data. In addition to the 2002 NY40 analysis, we discuss the possibilities to distinguish between different models with only very few photometric and/or spectroscopic measurements spread over a range of phase angles.Comment: 6 pages, 4 figures, A&A accepte

The fluorine abundance in a Galactic Bulge AGB star measured from CRIRES spectra

We present measurements of the fluorine abundance in a Galactic Bulge Asymptotic Giant Branch (AGB) star. The measurements were performed using high resolution K-band spectra obtained with the CRIRES spectrograph, which has been recently installed at ESO's VLT, together with state-of-the-art model atmospheres and synthetic spectra. This represents the first fluorine abundance measurement in a Galactic Bulge star, and one of few measurements of this kind in a third dredge-up oxygen-rich AGB star. The F abundance is found to be close to the solar value scaled down to the metallicity of the star, and in agreement with Disk giants that are comparable to the Bulge giant studied here. The measurement is of astrophysical interest also because the star's mass can be estimated rather accurately (1.4 \lesssim M/\mathrm{M}_{\sun} \lesssim 2.0). AGB nucleosynthesis models predict only a very mild enrichment of F in such low mass AGB stars. Thus, we suggest that the fluorine abundance found in the studied star is representative for the star's natal cloud, and that fluorine must have been produced at a similar level in the Bulge and in the Disk.Comment: 11 pages, 1 figure, accepted for publication by Ap

Large Interstellar Polarisation Survey. LIPS I: FORS2 spectropolarimetry in the Southern Hemisphere

Polarimetric studies of light transmitted through interstellar clouds may give constraints on the properties of the interstellar dust grains. Traditionally, broadband linear polarisation (BBLP) measurements have been considered an important diagnostic tool for the study of the interstellar dust, while comparatively less attention has been paid to spectropolarimetric measurements. However, spectropolarimetry may offer stronger constraints than BBLP, for example by revealing narrowband features, and by allowing us to distinguish the contribution of dust from the contribution of interstellar gas. Therefore, we have decided to carry out a Large Interstellar Polarisation Survey (LIPS) using spectropolarimetric facilities in both hemispheres. Here we present the results obtained in the Southern Hemisphere with the FORS2 instrument of the ESO Very Large Telescope. Our spectra cover the wavelength range 380--950\,nm at a spectral resolving power of about 880. We have produced a publicly available catalogue of 127 linear polarisation spectra of 101 targets. We also provide the Serkowski-curve parameters, as well as the wavelength gradient of the polarisation position angle for the interstellar polarisation along 76 different lines of sight. In agreement with previous literature, we found that the best-fit parameters of the Serkowski-curve are not independent of each other. However, the relationships that we obtained are not always consistent with what was found in previous studies.Comment: Accepted by A&A (replaced on 12 October 2017 simply to correct a Metadata error

A comparison between Pa alpha and H alpha emission: The relation between HII region mean reddening, local gas density and metallicity

We measure reddenings to HII regions in NGC 2903, NGC 1512, M51, NGC 4449 and NGC 6946 from Hubble Space Telescope Pa alpha and H alpha images. Extinctions range from A_V ~ 5 - 0 depending upon the galaxy. For the galaxies with HST images in both lines, NGC 2903, NGC 1512 and M51, the Pa alpha and H alpha emission are almost identical in morphology which implies that little emission from bright HII regions is hidden from view by regions of comparatively high extinction. The scatter in the measured extinctions is only +- 0.5 mag. We compare the reddenings we measure in five galaxies using the Pa alpha to H alpha ratios to those measured previously from the Balmer decrement in the LMC and as a function of radius in M101 and M51. We find that luminosity weighted mean extinctions of these ensembles of HI regions are correlated with gas surface density and metallicity. The correlation is consistent with the mean extinction depending on dust density where the dust to gas mass ratio scales with the metallicity. This trend is expected if HII regions tend to be located near the mid-plane of a gas disk and emerge from their parent molecular clouds soon after birth. In environments with gas densities below a few hundred Msol/pc^2 star formation rates estimated from integrated line fluxes and mean extinctions are likely to be fairly accurate.Comment: accepted for publication in A

Improved orbital solution and masses for the very low-mass multiple system LHS 1070

We present a refined orbital solution for the components A, B, and C of the nearby late-M type multiple system LHS 1070. By combining astrometric datapoints from NACO/VLT, CIAO/SUBARU, and PUEO/CFHT, as well as a radial velocity measurement from the newly commissioned near infrared high-resolution spectrograph CRIRES/VLT, we achieve a very precise orbital solution for the B and C components and a first realistic constraint on the much longer orbit of the A-BC system. Both orbits appear to be co-planar. Masses for the B and C components calculated from the new orbital solution (M_(B+C) = 0.157 +/- 0.009 M_sun) are in excellent agreement with theoretical models, but do not match empirical mass-luminosity tracks. The preliminary orbit of the A-BC system reveals no mass excess for the A component, giving no indication for a previously proposed fourth (D) component in LHS 1070.Comment: published in A&A, 2008, 484, 429; added CFHT acknowledgemen

AN ISOCAM MID-IR SURVEY OF TMC-2 Searching for sub stellar objects

Abstract We are conducting a mid-infrared survey of the Taurus Molecular Cloud 2 complex (TMC-2) in order to identify new low mass members and build a more complete IMF down to the sub stellar regime. Here we present a preliminary analysis of one of the surveyed fields. This field contains two previously known members of TMC-2. Based on the observed mid-IR excess we identify 6 new member candidates. Assuming a distance of 140 pc we find luminosities of ∼1.5−3.5 10 −3 L for these objects, placing them squarely in the brown dwarf domain. In addition to the two known stars and the 6 new brown dwarf candidates, we do not detect more luminous stars or brown dwarfs with IR excesses

IRAS04496-6958: A luminous carbon star with silicate dust in the Large Magellanic Cloud

We describe ISO observations of the obscured Asymptotic Giant Branch (AGB) star IRAS04496-6958 in the Large Magellanic Cloud (LMC). This star has been classified as a carbon star. Our new ISOCAM CVF spectra show that it is the first carbon star with silicate dust known outside of the Milky Way. The existence of this object, and the fact that it is one of the highest luminosity AGB stars in the LMC, provide important information for theoretical models of AGB evolution and understanding the origin of silicate carbon stars.Comment: 4 pages, 3 figures, accepted for publication in A&A Letter