37 research outputs found
Optical spectroscopy of comets
Comets are pristine remnants of the Solar system, composed of dust and ice.
They remain inactive and undetectable for most of their orbit due to low
temperatures. However, as they approach the Sun, volatile materials sublimate,
expelling dust and creating a visible coma. Spectroscopic observations of
comets help the simultaneous study of both the gas emissions and reflected
sunlight from dust particles. By implementing a long slit, the spatial
variations in molecular emissions can be analysed to be further used for other
computations. Additionally, spatial information aids in extracting the
characteristic profile of the Af(rho) parameter, revealing insights into the
behaviour of dust emissions. A sufficiently long slit would prove advantageous
in extracting information about the emissions occurring at different parts of
the coma or even the tail. We can gain an overall comprehensive understanding
of a comet's chemical composition and dust emission by constructively utilising
low-resolution spectroscopy with the help of a long slit.Comment: 10 pages, 8 figures, accepted for publication in Bulletin de la
Soci\'et\'e Royale des Sciences de Li\`ege (2023
Mass function and dynamical study of the open clusters Berkeley 24 and Czernik 27
We present a photometric study of the open clusters Berkeley 24 (Be
24) and Czernik 27 (Cz 27). The radii of the clusters are determined as
2\farcm7 and 2\farcm3 for Be 24 and Cz 27, respectively. We use the Gaia Data
Release 2 (GDR2) catalogue to estimate the mean proper motions for the
clusters. We found the mean proper motion of Be 24 as mas
yr and mas yr in right ascension and declination
for Be 24 and mas yr and mas yr for
Cz 27. We used probable cluster members selected from proper motion data for
the estimation of fundamental parameters. We infer reddenings =
mag and mag for the two clusters. Analysis of
extinction curves towards the two clusters show that both have normal
interstellar extinction laws in the optical as well as in the near-IR band.
From the ultraviolet excess measurement, we derive metallicities of [Fe/H]=
dex and dex for the clusters Be 24 and Cz 27,
respectively. The distances, as determined from main sequence fitting, are
kpc and kpc. The comparison of observed CMDs with
isochrones, leads to an age of Gyr and Gyr for
Be 24 and Cz 27, respectively.
In addition to this, we have also studied the mass function and dynamical
state of these two clusters for the first time using probable cluster members.
The mass function is derived after including the corrections for data
incompleteness and field star contamination. Our analysis shows that both
clusters are now dynamically relaxedComment: 16 pages including 8 tables. 22 figures. Accepted by MNRA
Effect of a plant versus animal based diet on lipid profile of yoga practicing medical students: a pilot study
Background: Foods play an important role in human health. An excess accumulation of cholesterol in the body is one of the main causes of cardio vascular disease, hypertension, type 2 diabetes mellitus, dyslipidemia and mortality. In the interests of food safety and public health, plants and their compounds are now re-emerging as an alternative approach to treat gastrointestinal diseases. The present study was designed to discuss changes in blood cholesterol levels after the consumption of animal based (non vegetarian) and plant based (vegetarian) food on yoga practising medical students.Methods: Of 81 subjects, a total of 60 subjects within the age group 18 to 22 years were selected for the study and were divided into two groups, non-vegetarian diet group (group A; n=30) and vegetarian diet group (group B; n=30). Subjects in the group A were given a non vegetarian diet and group B a vegetarian diet for a period of 10 days. Assessments were done at baseline and after 10 days.Results: There were no statistically significant changes seen in the lipid profiles of group B and group A after the application of a paired t test. In this study the mean value of total cholesterol, serum triglyceride, serum LDL and serum VLDL were found to be slightly higher in vegetarian group than the non-vegetarian group. Mean value of serum HDL was found to be higher in non-vegetarian group than the vegetarian.Conclusions: The present study concludes that there are more changes in the pre and post lipid profile assessments of the vegetarian group in comparison to the non-vegetarian group
Photometric and spectroscopic study of periodic carbon-chain depleted comets from Belgian and Indian observatories
Optical polarimetry of the blazar CGRaBS~ J0211+1051 from MIRO
We report the detection of high polarization in the first detailed optical
linear polarization measurements on the BL Lac object CGRaBS J0211+1051, which
flared in -rays on 2011 January 23 as reported by Fermi. The
observations were made during 2011 January 30 - February 3 using
photo-polarimeter mounted at the 1.2m telescope of Mt Abu InfraRed
Observatory(MIRO). The CGRaBS J0211+1051 was detected to have degree of polarization (DP) with steady position angle (PA) at
43 on 2011 January 30. During Jan 31 and Feb 1, while polarization
shows some variation, position angle remains steady for the night. Several
olarization flashes occurred during February 2 and 3 resulting in changes in
the DP by more than 4% at short time scales ( 17 to 45 mins). A mild
increase in the linear polarization with frequency is noticed during the nights
of February 2 & 3. The source exhibited significant inter-night variations in
the degree of polarization (changed by about 2 to 9%) and position angle
(changed by 2 to 22) during the five nights of observations. The
intra-night activity shown by the source appears to be related to turbulence in
the relativistic jet. Sudden change in the PA accompanied by a rise in the DP
could be indicative of the fresh injection of electrons in the jet. The
detection of high and variable degree of polarization categorizes the source as
low energy peaked blazar.Comment: 14-pages including 3-figure