Periodic UV modulation of X1850 — 087: a double degenerate binary in the globular cluster NGC 6712?
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چکیده
منابع مشابه
Low - energy absorption towards the ultra - compact X – ray binary 4 U 1850 − 087 located in the globular cluster NGC 6712
We report the results of two XMM–Newton observations of the ultra-compact low-mass X–ray binary 4U 1850−087 located in the galactic globular cluster NGC6712. A broad emission feature at 0.7 keV was detected in an earlier ASCA observation and explained as the result of an unusual Ne/O abundance ratio in the absorbing material local to the source. We find no evidence for this feature and derive N...
متن کامل1 Xmm-newton Results on the Ultracompact Low Mass X–ray Binary 4u 1850-087 in the Globular Cluster Ngc 6712
We report on preliminary results from our XMM-Newton observation of the Low Mass X-ray Binary 4U 1850-087, located in the galactic globular cluster NGC 6712. It is an ultracompact binary system, with an orbital period of 20.6 min. In previous low-resolution X-ray observations 4U 1850-087 displayed a soft excess residual around 0.7 keV, possibly indicative of the presence of a high Ne/O ratio, a...
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We present extensive UBVR photometry of the Galactic globular cluster (GGC) NGC6712 obtained with the ESO Very Large Telescope (VLT) which reach down to two magnitudes below the main sequence turn-off and allows us for the first time to determine the age of this cluster. By using the apparent luminosity of the zero age horizontal branch (ZAHB), VZAHB = 16.32 ± 0.05 and the stellar main sequence...
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We have carried out extensive VLT–FORS1 observations covering a fair fraction of the intermediate metallicity globular cluster NGC 6712 in the V and R bands. We derive accurate colour–magnitude diagrammes (CMD) and luminosity functions (LFs) of the cluster main sequence (MS) for four overlapping fields extending from the centre of the cluster out to a radius of ∼ 10 ′ , well beyond the nominal ...
متن کاملThe Peculiar Sdb Ngc 6121-v46: a Low-mass Double Degenerate Ellip- Soidal Variable in a Globular Cluster
The variable sdB known as V46 in the globular cluster M4 has remained enigmatic since its discovery almost 10 years ago. We present here radial velocity measurements obtained from medium-resolution VLT/FORS2 spectra that show variations at twice the period of the luminosity changes. This implies that the system is an ellipsoidal variable. Unlike the other sdB binaries of this nature, the fundam...
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ژورنال
عنوان ژورنال: Monthly Notices of the Royal Astronomical Society
سال: 1996
ISSN: 0035-8711,1365-2966
DOI: 10.1093/mnras/282.3.l37