Hakim L Malasan - Academia.edu (original) (raw)
Papers by Hakim L Malasan
Journal of Multidisciplinary Academic, May 19, 2019
Observatorium Astronomi Lampung (OAL) merupakan observatorium kedua di Indonesia yang dibangun di... more Observatorium Astronomi Lampung (OAL) merupakan observatorium kedua di Indonesia yang dibangun di Gunung Betung dari hasil konsorsium antara Pemerintah Provinsi Lampung, Institut Teknologi Sumatera, dan Institut Teknologi Bandung. OAL dapat dijadikan sebagai titik baru sebagai laboratorium astronomi di belahan langit ekuator. Pada kesempatan ini akan membahas aspek teknis instrumen yang terdapat di OAL seperti teleskop, analisator, dan detektor. Optimalisasi pemanfaatan instrumen dari hasil simulasi konfigurasi antara teleskop, analisator, dan detektor dengan hasil terbaik jika konfigurasi tersebut antara teleskop 0,7 meter dengan filter Baader UBVRI serta detektor CCD FLI PL16803. Fasilitas instrumen yang dimiliki OAL didedikasikan untuk kegiatan penelitian, pendidikan, dan edukasi pelayanan publik. Dengan kehadiran OAL diharapkan mampu memberikan nilai positif baik untuk masyarakat Lampung maupun kemajuan ilmu pengetahuan terutama astronomi.
8th Asian-Pacific Regional Meeting, Volume II, 2002
We present new photometric data for 14 Galactic open clusters in the anti-galactic center region,... more We present new photometric data for 14 Galactic open clusters in the anti-galactic center region, observed with the 65-cm telescope at Gunma Astronomical Observatory, providing an additional sample of old open clusters to refer to the history of cluster formation and the chemical evolution in the Galactic disk. Parameters of the clusters, i.e. the age, the metallicity, the distance, and the reddening, are estimated by fitting Padova isochrones in the color-magnitude diagram. While no clusters were estimated to be as old as young globular clusters, ages of 13 out of 14 of the clusters are older than the Hyades, up to an age of ˜3.6 Gyr.
Telah dilakukan studi mengenai pembentukan garis emisi pada Beta Lyrae. Beta Lyrae menjadi objek ... more Telah dilakukan studi mengenai pembentukan garis emisi pada Beta Lyrae. Beta Lyrae menjadi objek penelitian yang menarik selama 200 tahun terakhir dari berbagai metode pengamatan sinar-X, UV, optic, radio, dan inframerah. Kami memaparkan hasil pengamatan spektroskopi Beta Lyrae menggunakan spektrograf NEO R-1000 yang dipasang pada teleskop C-11 di Observatorium Bosscha. Pengamatan dilakukan selama bulan Agustus hingga September pada tahun 2015. Hasil pengamatan spektroskopi Beta Lyrae juga dibandingkan dengan data dari BeSS untuk melihat variasi perubahan spektrumnya terhadap waktu. Kemunculan profil garis invers P-Cygni pada panjang gelombang He I 5876 menjadi salah satu kasus yang menarik pada Beta Lyrae. Kami menduga bahwa profil invers P-Cygni dalam tahap evolusi spektrum sebelumnya berupa profil P-Cygni. Perubahan spektrum profil P-Cygni menjadi invers P-Cygni mengindikasikan bahwa keadaan lapisan gas terluar yang tidak stabil secara dinamik akibat proses transfer massa atau terjadi perubahan kecepatan rotasi yang berdampak pada perubahan laju kehilangan massa. Selain itu, juga terdapat fitur garis emisi yang kuat di panjang gelombang Hα λ 6563. Puncak profil garis Hα tersebut mengalami pergeseran panjang gelombang. Pergeseran garis dapat mengindikasikan adanya efek tekanan atau akibat dari ejeksi lapisan bintang.
IOP conference series, Jul 1, 2022
Journal of Physics: Conference Series, 2022
Vision is a continuous two-dimensional (2-D) image that can be perceived by human visual system. ... more Vision is a continuous two-dimensional (2-D) image that can be perceived by human visual system. Mathematically, image is a 2-D function that expresses the intensity of light. This research introduces the fundamental ideas of computer vision. We used OpenCV (Open-Source Computer Vision) to solve automatic image processing techniques, especially enhancement of contrast crescent visibility. We described an image using feature vectors to characterize and numerically to quantify the contents of an image. Then, we compared several techniques for increasing image quality, such as Basic contrast, Binary thresholding, Otsu thresholding, Histogram equalization, and Adaptive Histogram equalization. Finally, we calculated the statistical features of the image before and after enhancement process, and also decided to choose the best enhancement technique that will be implemented on a self-constructed cascade classifier in the future.
Journal of Physics: Conference Series, 2022
We report low and intermediate resolution spectra of the recurrent nova RS Oph taken at two obser... more We report low and intermediate resolution spectra of the recurrent nova RS Oph taken at two observatories. A low resolution spectrum (R ≈ 1000) was taken at ITERA Astronomical Observatory (IAO) in Lampung by using 25 cm (f/8) RC Astrograph telescope equipped with a LISA Pack Spectrograph eight days after the outburst. Twenty intermediate spectra (R ≈ 5000) were taken on several consecutive nights using LHIRES III spectrograph attached to a 25 cm (f/10) Meade LX-200R telescope at Bosscha Observatory, Lembang. We identified significant change in the strength of atomic lines from low resolution spectrum compared to previous observations. A clear and distinct Balmer emission decrement can be seen from the spectrum. Our intermediate resolution spectroscopy revealed a variability of P-Cygni profile on a broad Hα line. The P-Cygni profile evolved and disappeared at recent observations. It is thought that there was a new shell formed after the outburst and later combined with the previous s...
IOP Conference Series: Earth and Environmental Science, 2021
In early 2021, a rare extraterrestrial object passed at high speed, followed by a powerful boom, ... more In early 2021, a rare extraterrestrial object passed at high speed, followed by a powerful boom, with a bright flare crossing the atmosphere and falling in Astomulyo Village, Punggur, Central Lampung, Indonesia. This object has been scientifically determining as a meteorite. Toward the spot where we first found it, we presented this object named Astomulyo meteorite. This research investigated its chemical properties using an X-ray fluorescence (XRF) analyzer. As the result, the major composition of this meteorite is Si (28.3-27.1%), Fe (22.1-19.8%), Mg (17.3-15.2%), Al (2.9-2.4%), Ca (1.7-1.9%), and S (1.0-0.97%). Its minor elements are Mn, Ni, Cr, P, and some trace elements such as Co, Ti, Sb, Sn, V, Cd, Zn. This meteorite suggested classifying as the H-Chondrites group. Fe, Ni, Al, and Ti enrichment occur on the meteorite’s surface. It is probably related to this meteorite origin and continuously processes until it falls to the Earth’s surface.
Bintang ganda gerhana V525 Sagittarii pertama kali ditemukan oleh O'Connell pada tahun 1934. ... more Bintang ganda gerhana V525 Sagittarii pertama kali ditemukan oleh O'Connell pada tahun 1934. Dari studi tersebut, V525 Sagittarii diklasifikasikan sebagai bintang ganda gerhana tipe β Lyrae. Publikasi mengenai parameter V525 Sagittari terakhir kali dipublikasikan oleh O'Connell pada tahun 1951. Tugas Akhir ini membahas pengamatan V525 Sagittarii dan analisis kurva cahaya dengan metode fitting kualitatif. Pengamatan dilakukan di Observatorium Bosscha, Lembang, dengan menggunakan instrumen berupa teleskop GAO-ITB Remote Telescope System dan detektor CCD ST9-XE yang dilengkapi filter Bessell BVRI. Hasil akhir dari Tugas Akhir ini adalah parameter fisis dan parameter orbit dari V525 Sagittari, yaitu inklinasi orbit (i), fraksi massa (q), fraksi luminositas dari kedua komponen (L/Ltot), dan radius relatif dari kedua komponen (rback). Parameter yang dihasilkan merupakan parameter dengan fitting yang paling cocok dengan kurva cahaya hasil pengamatan. Dari hasil pengamatan diketahui...
IOP Conference Series: Earth and Environmental Science, 2020
Spectroscopic observations of standard stars (spectrophotometric) have been carried out at Bossch... more Spectroscopic observations of standard stars (spectrophotometric) have been carried out at Bosscha Observatory ITB (latitude= 6°49′28″ S, longitude= 107°36′56″ E, altitude=1310 m) using the Celestron C-11 reflector (D=11 inches, F/10.0), equipped with NEO R-1000 spectrograph (Resolution of 1000), and ST-8XME CCD camera to deduce total atmospheric extinction curve. Spectrograms were reduced with the long-slit task in the Image Reduction and Analysis Facility (IRAF). The total extinction curve obtained from observation is decomposed into three main components, i.e. Rayleigh scattering, Ozone and water vapor absorptions, and extinction by aerosol. The extinction profile by Aerosol serves as an important indication on size and distribution of particulates as the main constituent of atmospheric pollutant. This pollutant can be resulted from natural process or anthropogenic activities. The behavior of atmospheric extinction over Bosscha Observatory based on long-term astronomical photomet...
Journal of Mathematical and Fundamental Sciences, 2019
H line variations of 8 B-emission (Be) stars are presented. Stars that are listed in the Bright ... more H line variations of 8 B-emission (Be) stars are presented. Stars that are listed in the Bright Star Catalogue were observed in 2009 at the Bosscha Observatory, Lembang, Indonesia. It was found that 4 stars showed phase changing from Be double-peaked to Be single-peaked emission line profiles, 1 showed single-peaked to double-peaked profiles, 1 showed double-peaked to Bnormal, while two other stars did not show phase changing. The stars also showed variations in the V/R and E/C values, which represent the strength of the emission lines. The phase changes were detected from a comparison of the observed data to the current data in the BeSS database.
Journal of Physics: Conference Series, 2019
Diffuse Interstellar Bands (DIBs) are set of absorption features, mostly at optical and near infr... more Diffuse Interstellar Bands (DIBs) are set of absorption features, mostly at optical and near infrared wavelengths, that are found in the spectra of reddened stars and other objects. DIBs are actively being investigated to understand the nature of their properties and carriers and also their roles in interstellar matter enrichment. Among of the proposed carriers is large carbonaceous molecules (fullerenes). Interestingly, such as C60 and C70 have been detected in Planetary Nebulae (PN) environment. This detection allows us to study DIBs in fullerene-rich space environment. In this work, we study the presence of DIBs in central star of planetary nebulae (CSPN) by using archival data of optical spectra observed with 8.1-m Gemini South Telescope and Gemini Multi-Object Spectrographs (GMOS, spectral range of 3900 Å - 5900 Å and resolution of R ∼ 2300) and also from 2.5-m Isaac Newton Telescope with IDS spectrograph (R ∼ 2300). We measured the equivalent width of 4430, 5870 and 6283 Å DIB...
Journal of Physics: Conference Series, 2019
We present the spectroscopic observation of β Lyrae, an interacting eclipsing binary, with orbita... more We present the spectroscopic observation of β Lyrae, an interacting eclipsing binary, with orbital rotation period of 12.9 days, with one component known as the B-emission (Be) star. The primary star is a B6-B8II of 3 M⊙ and the secondary is a 13 M⊙ B0.5V star. The secondary star is embedded in the accretion disk produced by the infalling matter from the primary star, and this disk is estimated as the source of the emission lines. The observations were conducted at Bosscha Observatory, Lembang, Indonesia from May to August 2018, using 10” Meade LX-200R Telescope (D = 254 f/D = 9.84), equipped with a Littrow High Resolution Spectrograph (LHIRES) III, grating of 1200 grooves/mm yielding in the resolution of R∼5900, and CCD SBIG ST-402 XME camera with backfocus at 17.5 mm. Seeing during observation was estimated to be 2 arc seconds. During this period, we have obtained 15 spectra in various wavelength coverage, 4 spectra covering around λλ = 5779 – 6046 ÅÅ (typical S/N = 0.02), 1 spect...
Journal of Physics: Conference Series, 2019
Diffuse interstellar bands (DIBs) are an enigmatic set of interstellar absorption features, obser... more Diffuse interstellar bands (DIBs) are an enigmatic set of interstellar absorption features, observed at optical and near infrared wavelengths in the spectra of reddened stars in our Galaxy also in other galaxies. Identifying the carriers of DIBs has been a longstanding challenge and is still very much a work in progress. In recent years, surveys of DIBs have been conducted, but mostly focus on strong bands. In this work, we extracted and measured DIBs recorded in the high-resolution stellar spectra of ε Auriga (ε Aur) and IQ Per observed by using Gunma Astronomical Observatory Echelle Spectrograph (GAOES) (spectral resolution R∼65000). Observations were aimed at obtaining high resolution spectra of double-lined detached eclipsing binaries. For each selected DIB, we performed spectral fitting of a combination of a smooth stellar continuum (polynomial function), an empirical DIB model, and a synthetic telluric transmission. The high-quality data allow us to measure not only strong and...
Journal of Physics: Conference Series, 2019
Observations of the central star planetary nebulae (CSPN) IC 4663 revealed its spectral features ... more Observations of the central star planetary nebulae (CSPN) IC 4663 revealed its spectral features similar to WN sequence of massive Wolf-Rayet (WR) stars. Because CSPN IC 4663 spectrum is dominated by broad He II and N V emission lines, it is classified as [WN3] spectral type. The similarity on the central stars composition of O(He) and IC 4663 provides evidence for evolutionary sequence [WN] → O(He). Evolution of CSPN IC 4663 followed evolution low-mass star, but experienced born-again scenario when it enters white dwarf phase. So it goes back to Asymptotic Giant Branch (AGB) phase. To investigate central star properties, the nebula and its evolutionary status, we constructed the spectral energy distribution (SED) model by using photoionization code CLOUDY based on data set from optic to far-IR wavelength (∼3 – 100 μm) and include the Postdam Wolf-Rayet (PoWR) stellar model atmosphere. The comparison between the nebular abundances from photoionization model result and AGB model give...
Journal of Physics: Conference Series, 2016
Spectroscopic observations in the wavelength range of λλ4000 — 8000 A of the planetary nebulae (P... more Spectroscopic observations in the wavelength range of λλ4000 — 8000 A of the planetary nebulae (PN), NGC 6543 and NGC 7662, have been undertaken in 2014 using the compact spectrograph attached to the 28-cm Schmidt-Cassegrainian reflector at Koyama Astronomical Observatory. We derived physical parameters of NGC 6543 and NGC 7662 from the analyses of observed emission lines, i.e. electron temperature, density, and elemental abundances. To obtain more reliable physical quantities of NGC 6543 and NGC 7662, the use of photoionization model is needed. We use the computer code, CLOUDY C13.3 to build detailed photoionization models of NGC 6543 and NGC 7662. Model of NGC 6543 and 7662 can be constructed by providing sufficient information on physical parameters of the central stars and the nebula. In this work, input parameters to construct the photoionization model of NGC 6543 and NGC 7662 are distance, temperature and luminosity of central star and nebula parameters. The model results were compared with observational result taken in 2014. Observed and modeled temperatures were deduced from [O III] λλ(4959 + 5007) A /λ4636 A and the electron density from [S II] λλ 6716/6731 A. There are some discrepancies between observed and modeled due to limitations inherent with the resolution and quality of spectroscopic data. Further spectroscopic observations with higher resolution of NGC 6543 and NGC 7662 is recommended.
Journal of Physics: Conference Series, 2016
The March 9th 2016 total solar eclipse observation was carried out at Universitas Palangkaraya, C... more The March 9th 2016 total solar eclipse observation was carried out at Universitas Palangkaraya, Central Kalimantan. Time-resolved imaging of the Sun has been conducted before, after, and during totality of eclipse while optical spectroscopic observation has been carried out only at the totality. The imaging observation in white light was done to take high resolution images of solar corona. The images were taken with a DSLR camera that is attached to a refractor telescope (d=66 mm, f/5.9). Despite cloudy weather during the eclipse moments, we managed to obtain the images with lower signal-to-noise ratio, including identifiable diamond ring, prominence and coronal structure. The images were processed using standard reduction procedure to increase the signal-to-noise ratio and to enhance the corona. Then, the coronal structure is determined and compared with ultraviolet data from SOHO to analyze the correlation between visual and ultraviolet corona. The spectroscopic observation was conducted using a slit-less spectrograph and a DSLR camera to obtain solar flash spectra. The flash spectra taken during the eclipse show emissions of H 4861 A, He I 5876 A, and H 6563 A. The Fe XIV 5303 A and Fe X 6374 A lines are hardly detected due to low signal-to-noise ratio. Spectral reduction and analysis are conducted to derive the emission lines intensity relative to continuum intensity. We use the measured parameters to determine the temperature of solar chromosphere.
Publications of The Korean Astronomical Society, 2015
(NARIT) has joined the BIMA Project as the main partner. This project aims to build an open-datab... more (NARIT) has joined the BIMA Project as the main partner. This project aims to build an open-database of eclipsing binary minima and to establish the orbital period of each system and its variations. The project is conducted on the basis of multisite monitoring observations of eclipsing binaries with magnitudes less than 19 mag. Differential photometry methods have been applied throughout the observations. Data reduction was performed using IRAF. The observations were carried out in BVRI bands using three different small telescopes situated in Indonesia, Thailand, and Chile. Computer programs have been developed for calculating the time of minima. To date, more than 140 eclipsing binaries have been observed. From them 71 minima have been determined. We present and discuss the O-C diagrams for some eclipsing binary systems.
We present new CCD photometric observation of V899 Herculis system which obtained in May-June 201... more We present new CCD photometric observation of V899 Herculis system which obtained in May-June 2010 at Bosscha Observatory ITB, Lembang Indonesia, using the 20.3 cm(f/10.0) Schmidt-Cassegrain GAO-ITB RTS telescope equipped with ST8 CCD camera. We secure 1 time of primary minimum. We employed Cubic Fit method tep{bre1973} to make minimum timing and define the primary minima. Discussion on the nature of V899 Her based on new O-C diagram analysis will be presented.
Journal of Multidisciplinary Academic, May 19, 2019
Observatorium Astronomi Lampung (OAL) merupakan observatorium kedua di Indonesia yang dibangun di... more Observatorium Astronomi Lampung (OAL) merupakan observatorium kedua di Indonesia yang dibangun di Gunung Betung dari hasil konsorsium antara Pemerintah Provinsi Lampung, Institut Teknologi Sumatera, dan Institut Teknologi Bandung. OAL dapat dijadikan sebagai titik baru sebagai laboratorium astronomi di belahan langit ekuator. Pada kesempatan ini akan membahas aspek teknis instrumen yang terdapat di OAL seperti teleskop, analisator, dan detektor. Optimalisasi pemanfaatan instrumen dari hasil simulasi konfigurasi antara teleskop, analisator, dan detektor dengan hasil terbaik jika konfigurasi tersebut antara teleskop 0,7 meter dengan filter Baader UBVRI serta detektor CCD FLI PL16803. Fasilitas instrumen yang dimiliki OAL didedikasikan untuk kegiatan penelitian, pendidikan, dan edukasi pelayanan publik. Dengan kehadiran OAL diharapkan mampu memberikan nilai positif baik untuk masyarakat Lampung maupun kemajuan ilmu pengetahuan terutama astronomi.
8th Asian-Pacific Regional Meeting, Volume II, 2002
We present new photometric data for 14 Galactic open clusters in the anti-galactic center region,... more We present new photometric data for 14 Galactic open clusters in the anti-galactic center region, observed with the 65-cm telescope at Gunma Astronomical Observatory, providing an additional sample of old open clusters to refer to the history of cluster formation and the chemical evolution in the Galactic disk. Parameters of the clusters, i.e. the age, the metallicity, the distance, and the reddening, are estimated by fitting Padova isochrones in the color-magnitude diagram. While no clusters were estimated to be as old as young globular clusters, ages of 13 out of 14 of the clusters are older than the Hyades, up to an age of ˜3.6 Gyr.
Telah dilakukan studi mengenai pembentukan garis emisi pada Beta Lyrae. Beta Lyrae menjadi objek ... more Telah dilakukan studi mengenai pembentukan garis emisi pada Beta Lyrae. Beta Lyrae menjadi objek penelitian yang menarik selama 200 tahun terakhir dari berbagai metode pengamatan sinar-X, UV, optic, radio, dan inframerah. Kami memaparkan hasil pengamatan spektroskopi Beta Lyrae menggunakan spektrograf NEO R-1000 yang dipasang pada teleskop C-11 di Observatorium Bosscha. Pengamatan dilakukan selama bulan Agustus hingga September pada tahun 2015. Hasil pengamatan spektroskopi Beta Lyrae juga dibandingkan dengan data dari BeSS untuk melihat variasi perubahan spektrumnya terhadap waktu. Kemunculan profil garis invers P-Cygni pada panjang gelombang He I 5876 menjadi salah satu kasus yang menarik pada Beta Lyrae. Kami menduga bahwa profil invers P-Cygni dalam tahap evolusi spektrum sebelumnya berupa profil P-Cygni. Perubahan spektrum profil P-Cygni menjadi invers P-Cygni mengindikasikan bahwa keadaan lapisan gas terluar yang tidak stabil secara dinamik akibat proses transfer massa atau terjadi perubahan kecepatan rotasi yang berdampak pada perubahan laju kehilangan massa. Selain itu, juga terdapat fitur garis emisi yang kuat di panjang gelombang Hα λ 6563. Puncak profil garis Hα tersebut mengalami pergeseran panjang gelombang. Pergeseran garis dapat mengindikasikan adanya efek tekanan atau akibat dari ejeksi lapisan bintang.
IOP conference series, Jul 1, 2022
Journal of Physics: Conference Series, 2022
Vision is a continuous two-dimensional (2-D) image that can be perceived by human visual system. ... more Vision is a continuous two-dimensional (2-D) image that can be perceived by human visual system. Mathematically, image is a 2-D function that expresses the intensity of light. This research introduces the fundamental ideas of computer vision. We used OpenCV (Open-Source Computer Vision) to solve automatic image processing techniques, especially enhancement of contrast crescent visibility. We described an image using feature vectors to characterize and numerically to quantify the contents of an image. Then, we compared several techniques for increasing image quality, such as Basic contrast, Binary thresholding, Otsu thresholding, Histogram equalization, and Adaptive Histogram equalization. Finally, we calculated the statistical features of the image before and after enhancement process, and also decided to choose the best enhancement technique that will be implemented on a self-constructed cascade classifier in the future.
Journal of Physics: Conference Series, 2022
We report low and intermediate resolution spectra of the recurrent nova RS Oph taken at two obser... more We report low and intermediate resolution spectra of the recurrent nova RS Oph taken at two observatories. A low resolution spectrum (R ≈ 1000) was taken at ITERA Astronomical Observatory (IAO) in Lampung by using 25 cm (f/8) RC Astrograph telescope equipped with a LISA Pack Spectrograph eight days after the outburst. Twenty intermediate spectra (R ≈ 5000) were taken on several consecutive nights using LHIRES III spectrograph attached to a 25 cm (f/10) Meade LX-200R telescope at Bosscha Observatory, Lembang. We identified significant change in the strength of atomic lines from low resolution spectrum compared to previous observations. A clear and distinct Balmer emission decrement can be seen from the spectrum. Our intermediate resolution spectroscopy revealed a variability of P-Cygni profile on a broad Hα line. The P-Cygni profile evolved and disappeared at recent observations. It is thought that there was a new shell formed after the outburst and later combined with the previous s...
IOP Conference Series: Earth and Environmental Science, 2021
In early 2021, a rare extraterrestrial object passed at high speed, followed by a powerful boom, ... more In early 2021, a rare extraterrestrial object passed at high speed, followed by a powerful boom, with a bright flare crossing the atmosphere and falling in Astomulyo Village, Punggur, Central Lampung, Indonesia. This object has been scientifically determining as a meteorite. Toward the spot where we first found it, we presented this object named Astomulyo meteorite. This research investigated its chemical properties using an X-ray fluorescence (XRF) analyzer. As the result, the major composition of this meteorite is Si (28.3-27.1%), Fe (22.1-19.8%), Mg (17.3-15.2%), Al (2.9-2.4%), Ca (1.7-1.9%), and S (1.0-0.97%). Its minor elements are Mn, Ni, Cr, P, and some trace elements such as Co, Ti, Sb, Sn, V, Cd, Zn. This meteorite suggested classifying as the H-Chondrites group. Fe, Ni, Al, and Ti enrichment occur on the meteorite’s surface. It is probably related to this meteorite origin and continuously processes until it falls to the Earth’s surface.
Bintang ganda gerhana V525 Sagittarii pertama kali ditemukan oleh O'Connell pada tahun 1934. ... more Bintang ganda gerhana V525 Sagittarii pertama kali ditemukan oleh O'Connell pada tahun 1934. Dari studi tersebut, V525 Sagittarii diklasifikasikan sebagai bintang ganda gerhana tipe β Lyrae. Publikasi mengenai parameter V525 Sagittari terakhir kali dipublikasikan oleh O'Connell pada tahun 1951. Tugas Akhir ini membahas pengamatan V525 Sagittarii dan analisis kurva cahaya dengan metode fitting kualitatif. Pengamatan dilakukan di Observatorium Bosscha, Lembang, dengan menggunakan instrumen berupa teleskop GAO-ITB Remote Telescope System dan detektor CCD ST9-XE yang dilengkapi filter Bessell BVRI. Hasil akhir dari Tugas Akhir ini adalah parameter fisis dan parameter orbit dari V525 Sagittari, yaitu inklinasi orbit (i), fraksi massa (q), fraksi luminositas dari kedua komponen (L/Ltot), dan radius relatif dari kedua komponen (rback). Parameter yang dihasilkan merupakan parameter dengan fitting yang paling cocok dengan kurva cahaya hasil pengamatan. Dari hasil pengamatan diketahui...
IOP Conference Series: Earth and Environmental Science, 2020
Spectroscopic observations of standard stars (spectrophotometric) have been carried out at Bossch... more Spectroscopic observations of standard stars (spectrophotometric) have been carried out at Bosscha Observatory ITB (latitude= 6°49′28″ S, longitude= 107°36′56″ E, altitude=1310 m) using the Celestron C-11 reflector (D=11 inches, F/10.0), equipped with NEO R-1000 spectrograph (Resolution of 1000), and ST-8XME CCD camera to deduce total atmospheric extinction curve. Spectrograms were reduced with the long-slit task in the Image Reduction and Analysis Facility (IRAF). The total extinction curve obtained from observation is decomposed into three main components, i.e. Rayleigh scattering, Ozone and water vapor absorptions, and extinction by aerosol. The extinction profile by Aerosol serves as an important indication on size and distribution of particulates as the main constituent of atmospheric pollutant. This pollutant can be resulted from natural process or anthropogenic activities. The behavior of atmospheric extinction over Bosscha Observatory based on long-term astronomical photomet...
Journal of Mathematical and Fundamental Sciences, 2019
H line variations of 8 B-emission (Be) stars are presented. Stars that are listed in the Bright ... more H line variations of 8 B-emission (Be) stars are presented. Stars that are listed in the Bright Star Catalogue were observed in 2009 at the Bosscha Observatory, Lembang, Indonesia. It was found that 4 stars showed phase changing from Be double-peaked to Be single-peaked emission line profiles, 1 showed single-peaked to double-peaked profiles, 1 showed double-peaked to Bnormal, while two other stars did not show phase changing. The stars also showed variations in the V/R and E/C values, which represent the strength of the emission lines. The phase changes were detected from a comparison of the observed data to the current data in the BeSS database.
Journal of Physics: Conference Series, 2019
Diffuse Interstellar Bands (DIBs) are set of absorption features, mostly at optical and near infr... more Diffuse Interstellar Bands (DIBs) are set of absorption features, mostly at optical and near infrared wavelengths, that are found in the spectra of reddened stars and other objects. DIBs are actively being investigated to understand the nature of their properties and carriers and also their roles in interstellar matter enrichment. Among of the proposed carriers is large carbonaceous molecules (fullerenes). Interestingly, such as C60 and C70 have been detected in Planetary Nebulae (PN) environment. This detection allows us to study DIBs in fullerene-rich space environment. In this work, we study the presence of DIBs in central star of planetary nebulae (CSPN) by using archival data of optical spectra observed with 8.1-m Gemini South Telescope and Gemini Multi-Object Spectrographs (GMOS, spectral range of 3900 Å - 5900 Å and resolution of R ∼ 2300) and also from 2.5-m Isaac Newton Telescope with IDS spectrograph (R ∼ 2300). We measured the equivalent width of 4430, 5870 and 6283 Å DIB...
Journal of Physics: Conference Series, 2019
We present the spectroscopic observation of β Lyrae, an interacting eclipsing binary, with orbita... more We present the spectroscopic observation of β Lyrae, an interacting eclipsing binary, with orbital rotation period of 12.9 days, with one component known as the B-emission (Be) star. The primary star is a B6-B8II of 3 M⊙ and the secondary is a 13 M⊙ B0.5V star. The secondary star is embedded in the accretion disk produced by the infalling matter from the primary star, and this disk is estimated as the source of the emission lines. The observations were conducted at Bosscha Observatory, Lembang, Indonesia from May to August 2018, using 10” Meade LX-200R Telescope (D = 254 f/D = 9.84), equipped with a Littrow High Resolution Spectrograph (LHIRES) III, grating of 1200 grooves/mm yielding in the resolution of R∼5900, and CCD SBIG ST-402 XME camera with backfocus at 17.5 mm. Seeing during observation was estimated to be 2 arc seconds. During this period, we have obtained 15 spectra in various wavelength coverage, 4 spectra covering around λλ = 5779 – 6046 ÅÅ (typical S/N = 0.02), 1 spect...
Journal of Physics: Conference Series, 2019
Diffuse interstellar bands (DIBs) are an enigmatic set of interstellar absorption features, obser... more Diffuse interstellar bands (DIBs) are an enigmatic set of interstellar absorption features, observed at optical and near infrared wavelengths in the spectra of reddened stars in our Galaxy also in other galaxies. Identifying the carriers of DIBs has been a longstanding challenge and is still very much a work in progress. In recent years, surveys of DIBs have been conducted, but mostly focus on strong bands. In this work, we extracted and measured DIBs recorded in the high-resolution stellar spectra of ε Auriga (ε Aur) and IQ Per observed by using Gunma Astronomical Observatory Echelle Spectrograph (GAOES) (spectral resolution R∼65000). Observations were aimed at obtaining high resolution spectra of double-lined detached eclipsing binaries. For each selected DIB, we performed spectral fitting of a combination of a smooth stellar continuum (polynomial function), an empirical DIB model, and a synthetic telluric transmission. The high-quality data allow us to measure not only strong and...
Journal of Physics: Conference Series, 2019
Observations of the central star planetary nebulae (CSPN) IC 4663 revealed its spectral features ... more Observations of the central star planetary nebulae (CSPN) IC 4663 revealed its spectral features similar to WN sequence of massive Wolf-Rayet (WR) stars. Because CSPN IC 4663 spectrum is dominated by broad He II and N V emission lines, it is classified as [WN3] spectral type. The similarity on the central stars composition of O(He) and IC 4663 provides evidence for evolutionary sequence [WN] → O(He). Evolution of CSPN IC 4663 followed evolution low-mass star, but experienced born-again scenario when it enters white dwarf phase. So it goes back to Asymptotic Giant Branch (AGB) phase. To investigate central star properties, the nebula and its evolutionary status, we constructed the spectral energy distribution (SED) model by using photoionization code CLOUDY based on data set from optic to far-IR wavelength (∼3 – 100 μm) and include the Postdam Wolf-Rayet (PoWR) stellar model atmosphere. The comparison between the nebular abundances from photoionization model result and AGB model give...
Journal of Physics: Conference Series, 2016
Spectroscopic observations in the wavelength range of λλ4000 — 8000 A of the planetary nebulae (P... more Spectroscopic observations in the wavelength range of λλ4000 — 8000 A of the planetary nebulae (PN), NGC 6543 and NGC 7662, have been undertaken in 2014 using the compact spectrograph attached to the 28-cm Schmidt-Cassegrainian reflector at Koyama Astronomical Observatory. We derived physical parameters of NGC 6543 and NGC 7662 from the analyses of observed emission lines, i.e. electron temperature, density, and elemental abundances. To obtain more reliable physical quantities of NGC 6543 and NGC 7662, the use of photoionization model is needed. We use the computer code, CLOUDY C13.3 to build detailed photoionization models of NGC 6543 and NGC 7662. Model of NGC 6543 and 7662 can be constructed by providing sufficient information on physical parameters of the central stars and the nebula. In this work, input parameters to construct the photoionization model of NGC 6543 and NGC 7662 are distance, temperature and luminosity of central star and nebula parameters. The model results were compared with observational result taken in 2014. Observed and modeled temperatures were deduced from [O III] λλ(4959 + 5007) A /λ4636 A and the electron density from [S II] λλ 6716/6731 A. There are some discrepancies between observed and modeled due to limitations inherent with the resolution and quality of spectroscopic data. Further spectroscopic observations with higher resolution of NGC 6543 and NGC 7662 is recommended.
Journal of Physics: Conference Series, 2016
The March 9th 2016 total solar eclipse observation was carried out at Universitas Palangkaraya, C... more The March 9th 2016 total solar eclipse observation was carried out at Universitas Palangkaraya, Central Kalimantan. Time-resolved imaging of the Sun has been conducted before, after, and during totality of eclipse while optical spectroscopic observation has been carried out only at the totality. The imaging observation in white light was done to take high resolution images of solar corona. The images were taken with a DSLR camera that is attached to a refractor telescope (d=66 mm, f/5.9). Despite cloudy weather during the eclipse moments, we managed to obtain the images with lower signal-to-noise ratio, including identifiable diamond ring, prominence and coronal structure. The images were processed using standard reduction procedure to increase the signal-to-noise ratio and to enhance the corona. Then, the coronal structure is determined and compared with ultraviolet data from SOHO to analyze the correlation between visual and ultraviolet corona. The spectroscopic observation was conducted using a slit-less spectrograph and a DSLR camera to obtain solar flash spectra. The flash spectra taken during the eclipse show emissions of H 4861 A, He I 5876 A, and H 6563 A. The Fe XIV 5303 A and Fe X 6374 A lines are hardly detected due to low signal-to-noise ratio. Spectral reduction and analysis are conducted to derive the emission lines intensity relative to continuum intensity. We use the measured parameters to determine the temperature of solar chromosphere.
Publications of The Korean Astronomical Society, 2015
(NARIT) has joined the BIMA Project as the main partner. This project aims to build an open-datab... more (NARIT) has joined the BIMA Project as the main partner. This project aims to build an open-database of eclipsing binary minima and to establish the orbital period of each system and its variations. The project is conducted on the basis of multisite monitoring observations of eclipsing binaries with magnitudes less than 19 mag. Differential photometry methods have been applied throughout the observations. Data reduction was performed using IRAF. The observations were carried out in BVRI bands using three different small telescopes situated in Indonesia, Thailand, and Chile. Computer programs have been developed for calculating the time of minima. To date, more than 140 eclipsing binaries have been observed. From them 71 minima have been determined. We present and discuss the O-C diagrams for some eclipsing binary systems.
We present new CCD photometric observation of V899 Herculis system which obtained in May-June 201... more We present new CCD photometric observation of V899 Herculis system which obtained in May-June 2010 at Bosscha Observatory ITB, Lembang Indonesia, using the 20.3 cm(f/10.0) Schmidt-Cassegrain GAO-ITB RTS telescope equipped with ST8 CCD camera. We secure 1 time of primary minimum. We employed Cubic Fit method tep{bre1973} to make minimum timing and define the primary minima. Discussion on the nature of V899 Her based on new O-C diagram analysis will be presented.