26 research outputs found
Phenylketonuria in Portugal: Genotype-Phenotype Correlations Using Molecular, Biochemical, and Haplotypic Analyses
The impairment of the hepatic enzyme phenylalanine hydroxylase (PAH) causes elevation of phenylalanine levels in blood and other body fluids resulting in the most common inborn error of amino acid metabolism (phenylketonuria). Persistently high levels of phenylalanine lead to irreversible damage to the nervous system. Therefore, early diagnosis of the affected individuals is important, as it can prevent clinical manifestations of the disease.info:eu-repo/semantics/publishedVersio
New asymptotic giant branch carbon stars in the galactic halo
SPRINGER has CopyrightInternational audienceFor the first time the data on the eight confirmed or candidate carbon (C) stars found mainly fromobjective-prism plates are presented. By using the Catalina database of lightcurves, we find that allthese stars are pulsating, allowing a distance to be estimated through the K-band Period-Luminosity(PL) relation. This relation does not depend on spectral type (M or C) and distances are reliable even forC candidates. Seven stars are more than 10 kpc from the galactic plane, suggesting they do not belong tothe galactic disk. We also find one star located at about 180 kpc from the Sun, being one of the mostdistant star in the Galaxy. Many of these new C stars are relatively blue. Some comments are alsoprovided on seven other known halo carbon stars for which either a pulsation period is obtained, orbecause they were not included in previous works on halo C stars
FBS 0137+400: an N-type semiregular variable carbon star
International audienc
New CH Carbon Stars Found in the DFBS
International audienceIn this paper, we discuss the nature of three new carbon © stars discovered in the Digitized First Byurakan Survey (DFBS). The three stars show early-type spectra in the DFBS. To better characterize these objects, medium-resolution CCD spectra were obtained. These stars show spectral features typical to CH-giant
New Carbon Stars Confirmed in the Digitized First Byurakan Survey Database
Published in Astrofizika, 62, 4, 643-647, November 2019International audienc
The Digitized First Byurakan Survey Data Base. Late-Type Stars Candidates. New Confirmations. I
International audienceThe Digitized First Byurakan Survey (DFBS) is the digitized version of the First Byurakan Survey (FBS, or Markarian survey). The FBS was the first systematic survey of the extragalactic sky. This objective-prism survey was carried out in 1965-1980 by B.E.Markarian and his colleagues using the 1 m Schmidt telescope of the Byurakan Astrophysical Observatory and resulted in discovery of 1517 UVX-excess (Markarian) galaxies. FBS low-resolution spectral plates have been used for a long time to search and study faint Late-Type Stars (LTS, M-type and C stars) at high Galactic latitudes. A total of 18 lists of the FBS LTS were published between 1990 and 2016. We report newly confirmed C and M giants, and also large amount of M dwarfs based on the Gaia DR3 BP/RP low-resolution spectroscopic data base. Some of the newly confirmed M dwarfs presents binary systems. Some of them are new eclipsing binaries. In our previous studies of the DFBS spectral plates, all were presented as LTS candidates. Gaia high-accuracy astrometric and photometric data and Transiting Exoplanet Survey Satellite (TESS) data are used to characterize these new confirmed LTS. TESS phase-dependent light curves show rotational modulations and flares for many new M dwarfs. This confirmations of the large number of completely new objects represents a very significant extension in the census of M giants, faint N-type Asymptotic Giant Branch C stars, CH-type C giants at high Galactic latitudes, and M dwarfs in the solar vicinity. Some objects are located more than 7 kpc from the Galactic plane. Ultimately, we aim to present value-added catalog and update the FBS LTS catalog. Note that a large amount of the blue stellar objects with UVX-excess and numerous of emission line objects were also detected
TYC 1417-891-1 and TYC 1478-742-1: Eclipsing Variable Stars. The Gaia EDR3 and TESS Photometric Data
International audienceBased on the TESS (Transiting Exoplanet Survey Satellite) phase dependent light curves, we confirm the eclipsing type variability nature for two G-type dwarfs: TYC 1417-891-1 and TYC 1478-742-1. Both objects show EA (Algol-type) light curves morphology. Orbital period for TYC 1417-891-1 is P ≈ 8.0 day and for TYC 1478-742-1, P ≈ 13.6 day. We present Gaia EDR3 and TESS catalogue important physical parameters as well as LAMOST spectra. Both objects are relatively bright and are located at a distance of 260.59 (±3.21) pc (TYC 1417-891-1) and 117.42 (±0.74) pc (TYC 1478-742-1). The TESS light curve of TYC 1478-742-1 shows also flares as well. We discuss possible nature of the secondary and faint objects around these stars
Investigation of Faint Galactic Carbon Stars from the First Byurakan Spectral sky Survey. Optical Variability. I. N-Type AGB Carbon Stars. K-band Absolute Magnitudes and Distances
International audienceThe goal of this paper is to present an optical variability study of the comparatively faint carbon (C) stars which have been discovered by searching the First Byurakan Survey (FBS) low-resolution (lr) spectral plates at high Galactic latitudes using recent wide-area variability databases. The light curves from the Catalina Sky Survey (CSS) and Northern Sky Variability Survey (NSVS) databases were exploited to study theit variability nature. In this paper, first in this series, the variability classes are presented for 54 N-type Asymptotic Giant Branch (AGB) C stars. One finds that 9 stars belongs to the group of Mira-type, 43 are Semi-Regular (SR), and 2 stars are Irregular (Irr)-type variables. The variability types of 27 objects has been established for the first time. K-band absolute magnitudes, distances, and height from the Galactic plane were estimated for all of them. We aim to better understand the nature of the selected C stars through spectroscopy, 2MASS photometric colors, and variability data. Most of the tools used in this study are developed within the framework of the Astronomical Virtual Observatory
M Dwarfs Found In The First Byurakan Spectral Sky Survey Data Base. Gaia EDR3 And TESS Data. Some Preliminary Results
In order to gain more information on the 236 M dwarfs identified in the First Byurakan Survey (FBS) low-resolution (lr) spectroscopic database, Gaia EDR3 high-accuracy astrometric and photometric data and Transiting Exoplanet Survey Satellite (TESS) data are used to characterize these M dwarfs and their possible multiplicity
Investigations of the Periodic Variables in the Catalina and Linear Databases
International audienceIn this study we continue spectral class determinations for large numbers of optically faint periodic variables taken from the Catalina Surveys Data Release 1 (CSDR1) and LINEAR data sets. Spectral classes and physical parameters are presented for 1184 periodic variables with periods P ≥ 10 days, taken from modern large sky area spectroscopic and photometric databases, including LAMOST (Large Sky Area Multi-Object Fiber Spectroscopic Telescope), SDSS (Sloan Digital Sky Survey), the Hamburg Quasar Survey (HQS), the Hamburg/ESO Survey (HES), and Gaia Data Release 2 (DR2). In Gaia DR2 catalogue, luminosities are presented for 276 objects and radial velocities (RV) for 108 objects out of 1184. Spectral classes were confirmed for more than 650 objects. The majority of the variables are found to be F, G, K, M dwarfs and giants, a few dozen carbon (C) stars (N-type Asymptotic Giant Branch (AGB) stars), and a few S stars. Some periodic variables are blue objects, such as B and A stars. The periods are in the range 10 ≤ P ≤ 1504 days and Catalina magnitudes in range 11.5 ≤ V ≤ 20.0 mag. Finding new and faint evolved AGB stars in the halo of our Galaxy is the first priority. A catalogue containing multiparameter data for 1184 periodic variables from modern astronomical databases has been generated