18 research outputs found
Searching for Extraterrestrial Amino Acids in a Contaminated Meteorite: Amino Acid Analyses of the Canakkale L6 Chondrite
Amino acids can serve as important markers of cosmochemistry, as their abundances and isomeric and isotopic compositions have been found to vary predictably with changes in parent body chemistry and alteration processes. Amino acids are also of astrobiological interest because they are essential for life on Earth. Analyses of a range of meteorites, including all groups of carbonaceous chondrites, along with H, R, and LL chondrites, ureilites, and a martian shergottite, have revealed that amino acids of plausible extraterrestrial origin can be formed in and persist after a wide range of parent body conditions. However, amino acid analyses of L6 chondrites to date have not provided evidence for indigenous amino acids. In the present study, we performed amino acid analysis on larger samples of a different L6 chondite, Canakkale, to determine whether or not trace levels of indigenous amino acids could be found. The Canakkale meteor was an observed fall in late July, 1964, near Canakkale, Turkey. The meteorite samples (1.36 and 1.09 g) analyzed in this study were allocated by C. Y. Ornek, along with a soil sample (1.5 g) collected near the Canakkale recovery site
The final decline of Nova (V1974) Cygni 1992 and discovery of an associated extended emission nebulosity
New spectroscopic observations of Nova Cygni 1992 (V1974 Cyg) carried out in 1994-95 have shown a progressive decrease of the ionization level, made evident by the fading or disappearance of the emission lines of [Ne V], [Ne III], [Fe VII], [Fe VI] and [O III], which were outstanding in the 1992-93 spectra. An echelle spectrum obtained at Asiago in October 1995 clearly shows the complexity of the velocity field of the nova. By scanning three spectra in 1994-95 perpendicular to the direction of the dispersion along Hα, it has been found all around the nova an extended emission nebulosity, having an upper diameter of about 3arcmin in July 1994 and nearly 4arcmin in May and October 1995. By assuming that the excitation of this nebulosity was due to the ultraviolet radiation emitted by the nova in the 1992 outburst, we found the distance to the nova about 1.9+/-0.1kpc
Discovery of Irradiation Induced Variations in the Light Curve of the Classical Nova Cygni 2001 No.2 (V2275 Cyg)
We present the CCD photometry, light curve and time series analysis of the
classical nova V2275 Cyg (N Cyg 2001 No.2). The source was observed for 14
nights in total using an R filter in 2002 and 2003 with the 1.5 m
Russian-Turkish joint telescope (RTT150) at the TUBITAK (The Scientific and
Technical Research Council of Turkey) National Observatory in Antalya Turkey,
as part of a large program on the CCD photometry of Cataclysmic Variables
(CVs). We report the detection of two distinct periodicities in the light curve
of the nova : a) P_1=0.31449(15) d -- 7.6 h, b) P_2=0.017079(17) d -- 24.6 min.
The first period is evident in both 2002 and 2003 whereas the second period is
only detected in the 2003 data set. We interpret the first period as the
orbital period of the system and attribute the orbital variations to aspect
changes of the secondary irradiated by the hot WD. We suggest that the nova was
a Super Soft X-ray source in 2002 and, perhaps, in 2003. The second period
could be a QPO originating from the oscillation of the ionization front (due to
a hot WD) below the inner Lagrange point as predicted by King (1989) or a beat
frequency in the system as a result of the magnetic nature of the WD if steady
accretion has already been re-established.Comment: 6 pages and 8 figures. Accepted to be published in MNRAS main Journal
as it stand
A photometric study of SDSS J081256.85+191157.8: Detection of orbital and negative superhump periods
The results obtained from unfiltered photometric CCD observations of SDSS J081256.85+191157.8 made during 3 nights in January 2012 are presented. A period of 0.160151(d) +/- 0.000079 was detected in the data. This period is consistent with the previously proposed orbital period of P P-orb = 0.160151(79) day. A quasi-periodicity of 0.148159(86) day was discovered in all data. This period is a negative superhump period. Therefore we suggest that SDSS J081256.85+191157.8 is classified as a negative superhump system. An improved orbital ephemeris is also determined: T-min (HJD) = 2455929.510163(364) + 0.1600 46(46)*E. (C) 2013 Elsevier B.V. All rights reserved
Spectral evolution of Nova (V1494) Aql and its high velocity jets
Spectral evolution of the fast nova V1494 Aql was monitored soon
after its discovery in December 1999 to September 2000. The first spectra
showed prominent emission lines of H I and Fe II, while He I was seen in
absorption. The radial velocities of the absorption components of H I,
He I and N II rapidly increased (in the negative sense) during the early
decline stage, while those of Fe II remained nearly constant. When a
new spectrum was taken on February 6, 2000 after the seasonal interruption,
this nova was in the transition stage. The spectra in the transition stage
showed emission lines of H I, He I, He II, N II, N III, Si II, [N II], [O I],
[O III], [Fe II], [Fe VI], [Ca V] etc., hence the emission lines of Fe II had
disappeared. A quasi-periodic oscillation of luminosity with a time scale of
about days and a mean amplitude of about 1.2 mag in V band was
seen from February to the middle of April 2000. The emission lines of He II
and [Ca V] disappeared around a light maximum of the oscillation, while the
emission lines of N II and N III strengthened. At the
same time high velocity (-2900 and +2830 km s-1) broad emission wings of
H I lines appeared, which suggest an ejection of high velocity jets.
The excitation state increased throughout the nebular stage. The last
spectra taken in September 2000 showed highly excited emission lines up to
[Fe VII] and [Fe X] λ6374.5.
The interstellar extinction is estimated as from
the equivalent widths of the interstellar absorption components of Na I D1
and D2. Using this result, the distance to the nova is estimated as
kpc. The mass and the helium abundance of the ejecta are
estimated as 6.2 ±
1.4 10 and N(He)/N(H) ±
0.01, respectively. The electron density of the ejecta decreased as
during the nebular stage, where t is time
from light maximum. This low decline rate suggests that the ejecta had a
ring like shape as well a large mass loss which may have continued
throughout the nebular stage
Searching for superhump period of cataclysmic variable AY Psc
The results obtained from unfiltered photometric CCD observations of AY Psc made during 17, 20 and 12 nights, respectively, in 2003, 2004 and 2005 are presented. A period of 0.21732 +/- 0.00001 d was detected in the data. This period is consistent with the previously proposed orbital period of P(orb) = 0.2173209 d ((Diaz and Steiner, 1990)). Since this period was present in the light curves taken in all three years, with no apparent change in its value or amplitude. it is interpreted as the orbital period of this binary system. In addition, quasi-periodicities of 0.2057 +/- 0.0001 d, 0.2063 +/- 0.0001 d, 0.2072 +/- 0.0001 d for the years 2003, 2004 and 2005, respectively, were also discovered. These periods were interpreted as negative superhump periods and it was seen that they changes from year to year. Therefore AY Psc is then classified as a negative superhump system. (C) 2008 Elsevier B.V. All rights reserved
CCD photometry of V2275 Cygni (N Cyg 2001 No.2) in 2002-2003
We present the CCD photometry, light curve and time series analysis of the classical nova V2275 Cyg. The source is observed for 14 nights in total using standard R filters in 2002 and 2003 with the 1.5m Russian-Turkish joint telescope (RTT150) at the TUBITAK National Observatory (TUG) in Antalya Turkey. We report the detection of two periodicities in the light curve of the nova : a) P-1=0.31449(15) d, b) P-2=0.017079(17) d. We propose that the first period is the orbital period of the system as a result of the aspect changes of the secondary irradiated by the hot WD. The second period could be a QPO originating from the oscillation of the ionization front below the inner Lagrange point as predicted by King (1989) or could be a QPO/beat period related to the magnetic nature of the WD
Micro-Raman, FTIR, SEM-EDX and structural analysis of the Canakkale meteorite
This study demonstrates for the first time, the spectroscopic characterization of Canakkale Meteorite that fell at Canakkale, Republic of Turkey (40 degrees 8'44 '' N; 26 degrees 24'23 '' E). The olivine group [(Mg, Fe)(2)SiO4], enstatite [Mg2Si2O6] (one of the orthopyroxene minerals) and plagioclase were identified by the micro-Raman and FTIR spectroscopies and EDX-SEM analyses. This meteorite has not yet been classified in the World's Database of Meteorites. The aim of this study is to investigate this meteorite by vibrational spectroscopic techniques and open the possibility to classify it and list in the World's Database of Meteorites. (C) 2012 Elsevier B.V. All rights reserved