Multi-color Optical Variability of the TeV Blazar Mrk 501 in the Low-State [PDF]
New Astron.13:375-384,2008, 2008 We report results based on the monitoring of the BL Lac object Mrk 501 in the optical (B, V and R) passbands from March to May 2000. Observations spread over 12 nights were carried out using 1.2 meter Mount Abu Telescope, India and 61 cm Telescope at Sobaeksan Astronomy Observatory, South Korea.
arxiv +1 more source
On the discovery of K I 7699 A line strength variation during the 1982 - 1984 eclipse of Epsilon Aurigae [PDF]
New Astronomy 51 (2017), 2017 The discovery of K I 7699{\AA} line strength variations during the 1982-1984 eclipse of {\epsilon} Aurigae is described. The equivalent widths and radial velocities of the K I 7699{\AA} line derived from spectra obtained during 1981 November to 1983 July with the 2.1-meter Otto Struve reflector telescope of the McDonald observatory are presented.
arxiv +1 more source
Light Curve Analysis of SAO23229 [PDF]
Journal of Astronomy and Space Sciences, 1993 We have made UBV light curves of a newly discovered eclipsing binary, SAO23229 at Sobaeksan Astronomy Observatory. We determined a minimum light time of HJD2448636.1170+/-0.0005 that is 3 minutes later than predicted time, and founda peculiar light ...
Ho-Il Kim +3 more
doaj
Heliocentric Potential (HCP) Prediction Model for Nowscast of Aviation Radiation Dose [PDF]
Journal of Astronomy and Space Sciences, 2015 It is well known that the space radiation dose over the polar route should be carefully considered especially when the space weather shows sudden disturbances such as CME and flares.
Junga Hwang +4 more
doaj +1 more source
A novel algorithm for extracting frequent gradual patterns
Machine Learning with Applications, 2021 The extraction of frequent gradual pattern is an important problem in computer science and largely studied by the scientist’s community of research in data mining. A frequent gradual pattern translates a recurrent co-variation between the attributes of a
Tayou Djamegni Clémentin +2 more
doaj
Ionospheric measurements of relative coronal brightness during the total solar eclipses of 11 August, 1999 and 9 July, 1945 [PDF]
Annales Geophysicae, 2000 Swept-frequency (1-10 MHz) ionosonde measurements were made at Helston, Cornwall (50°06'N, 5°18'W) during the total solar eclipse on August 11, 1999. Soundings were made every three minutes.
C. J. Davis +9 more
doaj +1 more source
Close Binary System GO Cyg [PDF]
, 2011 In this study, we present long term photometric variations of the close binary system \astrobj{GO Cyg}. Modelling of the system shows that the primary is filling Roche lobe and the secondary of the system is almost filling its Roche lobe.
B. Kalomeni +48 more
core +2 more sources
TOI-199 b: A Well-characterized 100 day Transiting Warm Giant Planet with TTVs Seen from Antarctica
The Astronomical Journal, 2023 We present the spectroscopic confirmation and precise mass measurement of the warm giant planet TOI-199 b. This planet was first identified in TESS photometry and confirmed using ground-based photometry from ASTEP in Antarctica including a full 6.5 hr ...
Melissa J. Hobson +51 more
doaj +1 more source
Time variation of the fine structure constant in the early universe and the Bekenstein model [PDF]
, 2007 We calculate bounds on the variation of the fine structure constant at the time of primordial nucleosynthesis and at the time of neutral hydrogen formation. We use these bounds and other bounds from the late universe to test Bekenstein model.
Antoniadis +106 more
core +3 more sources
PSR B0809+74: Understanding Its Perplexing Subpulse-separation (P2) Variations [PDF]
Astron.Astrophys. 429 (2005) 999-1006, 2004 The longitude separation between adjacent drifting subpulses, $P_2$, is roughly constant for many pulsars. It was then perplexing when pulsar B0809+74 was found to exhibit substantial variations in this measure, both with wavelength and with longitude position within the pulse window.
arxiv +1 more source