ORCID Profile
0000-0002-5859-2796
Current Organisation
Universiti Malaya
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Publisher: Univ. of Malaya
Date: 30-06-2022
Abstract: Middle Age lunar crescent visibility criterion is criterion that was produced during 8th until 17th century. This includes al-Khawarizmi lunar crescent visibility criterion in 8th century until al-Lathiqi lunar crescent visibility criterion in 17th century. Numbers of review on mathematics and astronomy during the Middle Age, however the number of review that specifically written for Middle Age lunar crescent visibility criterion limited, with majority of review is written to study the historical of Middle Age science, astronomy, mathematics and geography as a whole, and not converge on lunar crescent visibility criterion. . Therefore, this article aimed to provide a review on Middle Age lunar crescent visibility criterion. The review is conducted using literature analysis, snowball literature search and specific inclusion and exclusion criteria. The review is performed based on 13 works on lunar crescent visibility criterion that pass the selection criteria. The review found out that most of the lunar crescent visibility criterion is based on al-Khawarizmi arc of separation and solar longitude, lunar crescent visibility criterion, with exception on Ibn Tariq, Ibn Qurra and Ibnu Yunus lunar crescent visibility criterion that adopt angular distance or elongation. The review suggest that a new outlook on Middle Age lunar crescent visibility criterion study can be done, by conducting an assessment on new data of moonsighting, and comparing with modern lunar crescent visibility criterion research.
Publisher: American Astronomical Society
Date: 24-01-2018
Publisher: AIP
Date: 2011
DOI: 10.1063/1.3573687
Publisher: AIP
Date: 2013
DOI: 10.1063/1.4803563
Publisher: IEEE
Date: 07-2011
Publisher: Oxford University Press (OUP)
Date: 12-10-2019
Abstract: Asteroseismology is a promising tool to study Galactic structure and evolution because it can probe the ages of stars. Earlier attempts comparing seismic data from the Kepler satellite with predictions from Galaxy models found that the models predicted more low-mass stars compared to the observed distribution of masses. It was unclear if the mismatch was due to inaccuracies in the Galactic models, or the unknown aspects of the selection function of the stars. Using new data from the K2 mission, which has a well-defined selection function, we find that an old metal-poor thick disc, as used in previous Galactic models, is incompatible with the asteroseismic information. We use an importance-s ling framework, which takes the selection function into account, to fit for the metallicities of a population synthesis model using spectroscopic data. We show that spectroscopic measurements of [Fe/H] and [α/Fe] elemental abundances from the GALAH survey indicate a mean metallicity of log (Z/Z⊙) = −0.16 for the thick disc. Here Z is the effective solar-scaled metallicity, which is a function of [Fe/H] and [α/Fe]. With the revised disc metallicities, for the first time, the theoretically predicted distribution of seismic masses show excellent agreement with the observed distribution of masses. This indirectly verifies that the asteroseismic mass scaling relation is good to within five per cent. Assuming the asteroseismic scaling relations are correct, we estimate the mean age of the thick disc to be about 10 Gyr, in agreement with the traditional idea of an old α-enhanced thick disc.
Publisher: Elsevier BV
Date: 10-2023
Publisher: Oxford University Press (OUP)
Date: 27-10-2017
No related grants have been discovered for Mohd Hafiz Mohd Saadon.