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As a national agency of aeronautics and space in Indonesia, LAPAN has a responsibility to advance space science in Indonesia and to encourage research collaborations in this field between Indonesia and international research institutes. This year, the Space Science Center of LAPAN starts to organize the International Symposium on Space Science (ISSS). We hope that the ISSS can be an annual symposium. This year, we organized this symposium on 25 September 2019. This one-day event is the first international symposium that aims to elaborate basic and applied researches on space science from Indonesia and abroad. In particular, as our theme for this symposium, we encourage researchers either from Indonesia or abroad to present their researches on space science in general for this symposium and we aspire to strengthen forecast operation in space weather and its application to the users in Indonesia.

We were surprised! The participants attending this one-day symposium reach 107 peoples. The participants came from Indonesia, Malaysia, Japan, and China. We design that the participants can present their work either in oral or poster types. Furthermore, the crucial factor for this symposium is that we facilitate the works from the participants that can be published at a journal with the peer-reviewed process. We have worked hard to process all accepted manuscripts reviewed by professionals and experts in the space science field. At least, one manuscript is under reviewed by one reviewer, and the handling editor decided whether a manuscript can be accepted or rejected mainly based on the reviewer's comments. Of 35 manuscripts submitted to our symposium, 25 manuscripts can be suitable for scientific publication.

As we mentioned before, the ISSS 2019 is the first symposium on space science held in Indonesia. We thank all participants who attend and support this symposium. Hopefully, we continue this symposium in the future. See you all in the future!

List of Coordinator, Co-coordinator, Secretariat, Proceeding Team, Scientific Committee, Reviewers are available in the pdf.

List of photos are available in this pdf.

All papers published in this volume of Journal of Physics: Conference Series have been peer reviewed through processes administered by the proceedings Editors. Reviews were conducted by expert referees to the professional and scientific standards expected of a proceedings journal published by IOP Publishing.

Wolf-Rayet (WR) stars exhibit broad emission lines in their spectra. Based on the featured lines, they are classified into three types: nitrogen-rich WN, carbon-rich WC, and oxygen-rich WO. Broad emission lines indicate high expansion velocity and also previous studies showed that WR stars possessed higher mass-loss rates compared with another type of stars. Thus, it is suggested that the expansion velocity and the mass loss of WR stars play a role in the enrichment of interstellar matter. Our observations were conducted between July 2018 and June 2019 using NEO-R1000 (R∼1000) spectrograph with spectral range 4500-7000Å at the Bosscha Observatory and consisted of WN and WC type stars. Data reduction and expansion velocities determination were carried out using IRAF with longslit-transform routine and Gaussian fitting respectively. To obtain mass-loss rates, we compared our observed spectra with models provided by Potsdam Wolf-Rayet Models (PoWR). In several cases, the contribution of WR stars can be directly observed as Wolf-Rayet nebulae, whose structures are influenced by the high expansion velocity of the nearby WR stars. Assuming that the total of WR stars in the Milky Way is ∼ 2600, we estimated that the population release ∼ 0.507 M⊙ of material annually into Galactic environment.

The bright sky caused by light pollution is a problem for astronomical research. One of the first steps in dealing with the effects of light pollution is to calculate the level of light pollution. Measurement of sky brightness using Sky Quality Meter (SQM) can be done massively through mobile campaign/observations. LAPAN conducted such observations at several places namely Sumatera Barat, Sumedang, Jawa Tengah, Jawa Timur and Kupang by using SQM attached on vehicles. Those campaigns covers 80 to 980 km journey and the total distance traveled was about 2870 km. The obtained data show that the sky brightness above regions surveyed vary from 10 magnitude per arcsec² (mpsas), especially around Surabaya, Jawa Timur to 22 mpsas. The results then compared radiance map of the Earth surface from Visible Infrared Imaging Radiometer Suite (VIIRS) aboard Suomi National Polar Orbiting Partnership (NPP). Moderate correlations between in-situ sky brightness data and the radiance map are achieved. Further analyses are required prior to utilization of those relations in the development of Indonesia's sky brightness map which is presumably more accurate than the existing global map of sky brightness.

Numerous spacecraft have been reported to experience failures or anomalies due to various sources such as solar and geomagnetic storms. One of the important keys to investigate anomalies on spacecraft is satellite local time (SLT) utilized to track satellite position in space. Since not every local time of anomaly was registered and recorded well especially for low Earth orbit (LEO) spacecraft, it is necessary to find a method to determine SLT. A Simplified General Perturbations-4 (SGP4) method has been applied to overcome the absence of SLT information in the satellite anomaly database. A series of DMSP satellites are employed for the case study. In addition, the AACGM model is also taken into account for mean local times (MLTs) calculation. The discrepancy of MLTs is found between the observation, calculation and AACGM model and supposedly comes from the TLE data, which seemingly gives rise to incorrect orbital parameters. The deviation of MLTs leads to different morphology of MLT distribution in which the observed MLTs scatter from dusk to midnight sector, whereas the others spread within the dusk and noon sectors of MLT.

Coronal holes are an area that appears dark in the corona, which is observable in EUV and X-ray wavelengths. This area has an open magnetic field structure. The magnetogram image showed that the coronal hole has one polarity (unipolar). Commonly, the shape and size of the coronal hole at the poles are related to the structural strength of the magnetic field. Because of this unipolar nature, the coronal hole becomes a source of the high-speed solar wind, which can cause a geomagnetic storm. The number, size, and position of the coronal hole vary as a function of the solar cycle, with the reversal of magnetic polarity every 11 years. The characteristics of the coronal hole will be different at the maximum and minimum phases of the solar cycle. Aims of this study are to determine the morphology of coronal hole based on the area, magnetic field strength, open magnetic flux, and the evolution of the coronal hole according to latitude during minimum solar activity (or spotless days) and maximum at the Solar Cycle 24. The method applied in this study is CHIMERA (Coronal Hole Identification via Multi-thermal Emission Recognition Algorithm). There are relations between magnetic field strength and magnetic flux with areas of coronal holes from September 2010 to May 2019 that follow the exponential and linear distributions.

The measurement of the Night Sky Brightness (NSB) has been done at the Observatorium Ilmu Falak Universitas Muhammadiyah Sumatera Utara (OIF UMSU) during the total lunar eclipse on 28 July 2018. NSB was measured using three Sky Quality Meters (SQMs). We were directing those SQMs to the eastern horizon, zenith, and the western horizon with a resolution of 2 seconds. The results showed that zenith direction SQM data had a change in NSB due to the lunar eclipse. Before the eclipse, the NSB was 14.78 mpsas, and the NSB during the total Moon phase was 18.03 mpsas. While the SQM data in the direction of the eastern and the western horizons are showing insignificant changes, those were 15.58 mpsas and 15.15 mpsas, respectively. These are because fog and light pollution originating from the city center of Medan are heavily influencing the area in the direction of the eastern and western horizons.

One of the key outstanding problems in studies of galaxy evolution is understanding the connection between AGN and star formation (SF). Nevertheless, finding the existence of an SF-AGN connection is still not clear which process dominates the energetic output in both local and high redshift Universe. We present 360 X-ray selected obscured (type 2) AGNs at redshift z < 1.5. We acquired star formation properties for those X-ray detected AGN which available in the Cosmological Evolution Survey (COSMOS) project. We compared the star formation properties for our X-ray detected AGNs and non-X-ray galaxies using starburstiness. The step further is analyzing the X-ray properties and starburstiness of X-ray detected AGN for proving the existence of a connection. The starburstiness distribution of X-ray detected AGNs shows some excess in low star forming activity compared with the non-AGN objects. This excess might be an interesting topic to analyze the AGN type. For X-ray detected AGNs, We found that X-ray activities arise both in high and lower star forming activity. From those properties relation, we conclude that the AGNs could be triggered by starburst either directly or delayed.

We present the results of 83 measurements of night sky brightness with portable photometers for five locations, namely the Bosscha Observatory, Cimahi, Bandung, Yogyakarta, and Kupang during the moonless days from years 2011 to 2018. In the first place, instead of the zenith direction, we also evaluated the night sky brightness in various angles of the zenith distances. At the beginning of the morning twilight, solar dips were significantly affected by light and air pollution. It can cause a pseudo night effect, resulting from absorption by particles of low atmospheric height, which is due to air pollution. The duration of twilight is also influenced by the pollution level. A new tool to determine the boundaries of astronomical, nautical, and civil twilight using sky brightness difference was introduced. We also recommend a preferred solar dip of 18.5° for Islamic fajr prayer in Indonesia with twilight duration at 70.5 minutes.

Star clusters are groups of stars that are bonded to each other by their gravitational forces. In general, star clusters are divided into the globular cluster and open cluster. There will always be some dynamic interactions in their lifetime, i.e. the process of relaxation and equipartition of interstellar encounter energy. The modeling is done by using King, Generalised King (GKing), Optimised Generalised King (OGKing), Elson Fall Freeman (EFF), Generalised Density Profile (GDP), and Restricted Generalised Density Profile (RGDP) profiles. Based on the Bayes factor, the results of a review of the density structure for star cluster Blanco 1 are dominated by King group profiles (King, GKing, and OGKing). Ellipticity values at the core radius (_rc and tidal radius (_rt obtained are $0.07_{ - 0.01}^{ + 0.56}$ and $0.10_{ - 0.01}^{ + 0.66}$, respectively. The estimation of the occurrence of mass segregation can be viewed from the value of κ. The κ valued obtained for Blanco 1 is $0.06_{ - 0.24}^{ + 0.10}$ means that it undergo some mass segregation. The total mass obtained using the tidal force relationship of gravitational interactions with the potential Galaxy is $1623_{ - 364}^{ + 273}M \odot$.

Diffuse interstellar bands (DIBs) are a collection of weak interstellar absorptions in the spectra of reddened objects. We have successfully measured three strong DIBs (i.e., λ 5780, 5797, and 6614 Å) on the spectra of 125 Galactic Archaeology with HERMES (GALAH) target stars. The fitting uses a template spectrum in order to extract and measure individual DIB. We applied a correlation study between DIBs and confirmed that DIBs are positively correlated with each other, meaning that their carrier(s) are co-existing in the interstellar medium. Also, DIBs are well-correlated with color excess E(B-V). From this result, which is in a good agreement with earlier studies, conclude that DIBs can be used as a tracer of the interstellar medium.

In the present paper, we investigate the impact of solar activity on Low Earth Orbiting (LEO) satellites. How the increase in the number of coronal mass ejections and solar flares raises the likelihood that sensitive instruments in space and will be damaged by energetic particles accelerated in these events. So, we study the effect of perturbation forces on the Keplerian orbital elements of two LEO satellites using atmosphere model NRLMSISE00. The equation of motion and the effect of all perturbation are solved by using a High-Precision Orbit Propagation (HPOP) model, with Runge-Kutta 7 method, this method was treated by Cowell's technique. In this respect we deduce that solar activity influences the upper atmosphere; this influence is mediated through rapid geomagnetic disturbances.

The recent advances in observational and computational techniques allow studying the formation and dynamical evolution of planetary systems at an unprecedented level. The formation and evolution of isolated planetary systems are challenging in itself and it is more complicated by the dense environments in which stars and planets are typically born. Here, we present an overview of the internal and external processes that govern the dynamical evolution of planetary systems, and we provide a brief overview of a selection of the computational tools that are presently available to carry out realistic simulations of planetary systems in dense stellar environments.

τ Ceti, a G8-V class star, has similar physical properties with our sun, even though most values are smaller and not as active as the sun. It has also been widely reviewed that this metal-poor population II star has terrestrial planetary systems, some of which are in the Habitable Zone. This paper aims to build the interior structure of τ Ceti through modeling experiments with Modules for Experiments in Stellar Astrophysics (MESA) program. The work began with the determination of several fundamental parameters obtained from previous observations of both interferometry and spectroscopy on several references, and also from basic calculations which are then used as input to build the model in MESA. Structural modeling has been carried out in accordance with current star conditions, which is in the main sequence phase. Finally, the result various physical parameters so-called stellar interior structure such as mass, luminosity, pressure, temperature, radius, and age, as well as zonal division of nuclear core (R < 0.23 R⊙,), radiative (0.23 < R⊙ < 0.54), and convective zone (0.54 < R⊙ < 0.775) were obtained.

Two star clusters can be located near each other as a result of either simultaneous birth or system encounters, and thus are called a binary star cluster system. We analyzed three candidates of binary cluster: ASCC 16-ASCC 21, NGC 6716-Collinder 394, and NGC 2547-Pozzo 1 based on Gaia DR2. Each pair have physical separations of 13 pc, 13 pc, and 42 pc. In order to constrain the binarity of the candidates, we investigated their morphology, age estimates, photometric mass, and kinematics.

Active regions, which are mainly responsible for the energetic blast from the Sun so-called flare, have a highly concentrated magnetic field. Almost all flares have been attributed to the dynamics of its magnetic field on the photosphere. One method to know the changings is through studying their properties using magnetogram data. The data that are obtained from Helioseismic Magnetic Imager (HMI) instruments onboard Solar Dynamics Observatory (SDO) have a good temporal resolution which can make a better analysis. We analyze three properties of photospheric magnetic field namely total photospheric magnetic free energy (TOTPOT), total unsigned vertical current (TOTUSJZ) and total unsigned current helicity (TOTUSJH) of the active region (AR) 12740 which produced almost M-class flare at the very minimum phase of solar cycle 24. Then, we compared their values to the average values of all the corresponding parameters for almost one solar cycle. The results showed that the values of each parameter in AR 12740 was below the average values of C-flare-productive ARs. The TOTPOT was half of the average while TOTUSJH and TOTUSJZ were around one-third of the average.

Centaurs are small bodies whose semi-major axes are located between Jupiter and Neptune. They have chaotic orbits and may be in orbital resonances with giant planets. An orbital resonance occurs when a simple commensurability presents between some fundamental frequencies of orbital elements. One of the resonance states is 1:1 (mean motion) resonance or co-orbital with the respected planet. This resonance can also occur in high inclination Centaurs. This study describes the results of long term orbital integration of a retrograde Centaur 2006 RJ2 (inclination of 165°) for 200,000 years. Resonance state of 2006 RJ2 was examined using the FAIR (Fast Identification of Mean Motion Resonance) method for 243 orbital clones with automation by developing Python codes. We report that 2006 RJ2 may be in retrograde 1:1 resonance with Saturn for about 160,000 years in the future. However, the clones exhibit chaotic orbits and show many temporally unstable resonances. Since the quality of its orbital elements is not quite precise, 2006 RJ2 shows a low possibility in the state of long retrograde 1:1 resonance with Saturn.

The differential rotation is the difference in the rate of rotation of each latitude in the Sun indicating that the Sun is not a solid body. The differential rotation is the result of the interaction between rotation and convection and causes dynamo circulation that affects the cycle of solar activity. In this research, we measured the coordinates of 304 sunspots umbra as tracer in the rising phase of the Solar Cycle 24 to obtain the differential rotation equation. Coordinates of sunspots were measured using AIA images at a wavelength of 4500 Å from SDO (Solar Dynamic Observatory) with JHelioviewer software. The areas of sunspots were measured using HMI (Helioseismic Magnetic Imager) images with ImageJ software. From the measurement, we derived the differential rotation equation and the relation of sidereal rotation and area of sunspots umbra. The differential rotation equation obtained in this research is ω(B) = (14.27 ± 0.01) - (0.78 ± 0.10) sin²B (°/day). There is a difference between the differential rotation equation of the northern and southern hemispheres that indicates the asymmetry between different hemispheres. We got the sidereal rotation of sunspots with area < 5 MH is 0.70% higher than sunspots with area > 15 MH.

In this study, the moonlit sky brightness model that incorporates extinction and scattering parameters were fitted to the observational data obtained at four locations across Indonesia namely Biak, Garut, Pasuruan and Sumedang. Possible parameters were sampled using Markov Chain Monte Carlo to construct posterior distributions of corresponding parameters. The typical values of extinction parameter are below 0.5 except for Pasuruan whose value almost reaches unity. Atmospheric scattering is represented by Rayleigh scattering factors with values of around 1.0 and Mie scattering factors which are an order magnitude higher than Rayleigh scattering factors. The results indicate that the tropical atmosphere of Indonesia tends to be more turbid than the atmosphere at higher latitudes though more studies are required to confirm this indication.

We report an optical spectroscopic observational program of emission-line objects at Bosscha Observatory. The observations were conducted on 18 nights between May to July 2019. We employ the spectrograph NEO-R1000 (R∼1000) equipped with SBIG ST-8 XME CCD camera attached to a 28 cm (F/10) telescope and the spectrograph LHIRES III (R∼5000) equipped with SBIG ST-402 CCD camera attached to a 25 cm (F/10) telescope. Data reduction has been carried out using longslit transform routines within the Image Reduction and Analysis Facility (IRAF). We have successfully obtained the spectra of 9 Wolf-Rayet (WR) stars, 13 B-emission (Be) stars, 2 Luminous Blue Variable (LBV) stars, 8 Herbig Ae/Be (HAeBe) stars, and 1 recurrent nova. The obtained spectra are presented and discussed in this paper.

The study of orbital dynamics and evolution of Solar system small-bodies like asteroids has been conducted regularly with the latest data to ensure and update our understanding of the object's motion, especially the ones located nearby the Earth. One of its examples is asteroid 469219 Kamo'oalewa, which currently known as an Earth Quasi-satellite (QS). In this article, we investigate the orbital dynamics of 469219 Kamo'oalewa by running an N-body numerical integration. It was calculated from its latest orbital solution at epoch JD 2458600.5 using Gauss-Radau scheme provided by IAS15 integrator, which available on REBOUND code package. We found that the co-orbital motion of the asteroid towards Earth happens during time interval (–19.7,19.5) thousand years, with QS–HS transition happening at that period. The current QS motion started 15 years ago and will be transitioning to HS at around 50 years from now. After losing its current state, it will orbit the Sun near the Earth as an Apollo asteroid. We also investigated the secular evolution of this asteroid and found the result that support its QS–HS transition nature. On some occasions like a long period of HS, we found several orbital characteristics that resemble Kozai–Lidov resonance, but it doesn't hold long before the transition to QS resumes.

Granular particles can be found on the asteroids in the form of regolith. Regolith is a pile of boulders and gravels that covers the surface of an asteroid and have various sizes. Brazil Nut Effect (BNE) is one of the well-known phenomena that happened in this sort of system. This phenomenon leads to occur a tendency for larger boulders to come up to the surface. Some asteroids like Eros and Itokawa show that BNE supposes to happen also in a low gravity environment. BNE in asteroid may be generated by seismic vibration that causes inter-particle collisions. The collisions are represented by contacts among particles, so that contact forces need to be counted in modeling BNE. This study aims to build a modeling of BNE in asteroid involving contact forces caused by inter-particle collisions during the seismic vibration. This study shows that contact forces have a positive role in BNE by inter-particle contacts. The contacts accommodate the system to keep larger boulders staying in the elevated height. In the model that only involves static friction (without rolling), the vector of normal forces dominates over the tangential one for the resultant forces. Uprising of the larger boulders has been observed in the simulation, but most of them are still buried underneath the smaller ones. It is predicted that a seismic vibration with large enough energy is needed to make all of the larger boulders to come up to the surface. With that result, the larger boulders observed on the surface of some asteroids nowadays are reasonably the result of BNE which caused by heavy bombardment by meteoroids in the early stage of Solar System formation that drives some high-energy seismic vibration.

Not only have interior structures, but stars also have an atmosphere. Physical processes and phenomena that occur in the atmosphere of a star also have a relationship with the stellar interior. One of them is the energy transport process produced from the stellar core and delivered to the surface and atmosphere of the star. The stellar atmospheric model is built by taking into account the changes in various parameters, such as mass depth (∫ ρ dx), temperature (T), gas pressure (P_gas), electron density (n_e), Rosseland absorption coefficient (κ_R), and radiation pressure (P_rad) to the changes in optical depth (τ) of the star. The stellar parameters used for building this model are from the LL Aquarii star which is a detached eclipsing binary star. The star system has a mass of 1.1949 M_⨀ for LL Aqr A and 1.0337 M_⨀ for LL Aqr B with effective temperatures of 6124 K and 5747 K respectively. The obtained atmospheric model is the result of bilinear interpolation of the Kurucz atmospheric grid model with T_eff and g parameters. The results of the LL Aqr atmospheric model become inputs for modeling the stars synthetic spectrum using the SPECTRUM program. Convolution with the rotational velocity of the star and spectral parameters of the spectrograph instrument used will produce a synthetic spectrum that corresponds to the spectrum acquired from observations. The results showed conformity with the observed spectrum with an O-C difference of 0.05 on average.

A self-gravity ofspherical granular particles in the two-dimensional system is simulated. Some of the spherical particles are bonded through a spring force to form composite particles. These spherical and composite particles are attracted to each other due to gravitational force and prevented from collapse into a single point by the normal force. A previous study reported that a two-dimensional monodispersed system will form a hexagonal close-packed (HCP) configuration. In this work, it will be perturbed by some of the composite particles that could have HCP form, simple cubic (SC) form, or a mix of SC-HCP (MSH) form. These forms can be categorized into SC family (□, I, L, T, F, H, E), HCP family (Δ, □, V, X), and MSH family (⌂, K, M, W, N, Z), that can be compacted to maximum contactopy through lock-and-key mechanism (KL). The compaction of some forms from the SC family is similar to the Tetris game, where the structure should be compacted before it could be eliminated in the game. In this work, not all forms from the three families are simulated. The particles in general tend to form a final configuration with the most compact form and the composite particles seems also to influence their surrounding particles to construct the configuration.

It has been reported that there is a discrepancy of 4σ in the neutron lifetime measurement with two methods, i.e., the trap method (measuring the number of neutrons remaining in the various time intervals) and beam method (measuring the number of protons formed from regulated neutrons currents). Fornal and Grinstein (2019) proposed that the possibility neutrons decay into the dark matter can explain this discrepancy. In this study, the author asses the consequence of the proposal by studying the impact on neutron stars with Hyperon. Based on our numerical calculation we found that dark matter may be present in the core of a neutron star because it only appears at very high densities, and the population is negligible with a maximum population of about 0.1%

We used ionosonde and GPS receivers during March–April in 2004–2005 and 2011–2015 to investigate the latitudinal variation of equatorial plasma bubble (EPB) occurrence rate in cases of strong and weak pre-reversal enhancement (PRE). The ionosonde at Chumphon in Thailand was used to estimate the PRE strength. Ten GPS receivers in Southeast Asia, ranging from magnetic latitude (ML) of 4.4°S to 21.6°S, were used to investigate the latitudinal variation of EPB occurrence rate. In the case of strong PRE, the EPB occurrence rates decrease from 38.9% to 34.9% at ML of 4.4°S–7.2°S. Continuously, the occurrence rate increases and reaches the peak (44%) at ML of 9.3°S; afterward, the occurrence rate rapidly decreases and reaches below 5% at ML of 21.6°S. In the case of weak PRE, the occurrence rate decreases from 21.8% at ML of 4.4°S, seems constant (15.3%–16%) at ML of 8.2°S–12.1°S, and reaches less than 5% at ML of 16.1°S. Generally, the EPB occurrence rate and its latitudinal extension in case of strong PRE are higher than that in case of weak PRE. Interestingly, we found that the latitudinal occurrence rate peak of the EPB in case of strong is farther than that in case of weak PRE.

Pc5 ULF waves have attracted significant attention and been studied through theory, simulation, and observations. To understand the generation mechanisms of ULF waves, one should consider frequency characteristics, solar wind parameters, and geomagnetic activity. Observation on Pc5 magnetic pulsations due to solar wind perturbations at the low latitudes currently has not been widely explored. In this paper, we analyzed the amplitude of Pc5 magnetic pulsations during magnetic storms on 7–8 September 2017. We also investigated the effect of shock in the solar wind on the amplitude of Pc5 magnetic pulsation. We used the magnetometer data of four stations in the Indonesian region, which is located at low latitude, the ACE satellite data, and the Dst index. To extract Pc5 magnetic pulsations, we used the second-order of Butterworth filter with applying the Hamming windowing method. The result shows that the fluctuation in solar wind dynamic pressure triggers the Pc5 pulsations with similar waveforms and the same phase in both components of H and D. Large southward Bz component of the interplanetary magnetic field accompanied by the increase of solar wind dynamic pressure caused the large and long duration of Pc5 pulsation.