Johny Setiawan

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The influence of surface chemistry and solution pH on the adsorption of benzene and toluene on activated carbon and its acid and heat treated forms were studied. A commercial coal-based activated carbon F-400 was chosen as carbon parent. The carbon samples were obtained by modification of F-400 by means of chemical treatment with HNO3 and thermal treatment(More)
We present the detailed spectroscopic analysis of 72 evolved stars, which were previously studied for accurate radial velocity variations. Using one Hyades giant and another well studied star as the reference abundance, we determine the [Fe/H] for the whole sample. These metallicities, together with the T eff values and the absolute V-band magnitude derived(More)
Deriving unambiguously the orbital parameters and masses of extrasolar planets requires at least 2-dimensional information on either the positions or motions of the planet directly (currently out of reach) or, indirectly, of the host star. The latter can be done with high-precision astrometry at the 10 microarcsec level. To achieve this goal, a consortium(More)
PRIMA, the instrument for Phase-Referenced Imaging and Micro-arcsecond Astrometry at the VLTI, is currently being developed at ESO. PRIMA will implement the dual-feed capability, at first for two UTs or ATs, to enable simultaneous interferometric observations of two objects that are separated by up to 1 arcmin. PRIMA is designed to perform narrowangle(More)
ESO’s PRIMA (Phase-Referenced Imaging and Micro-arcsecond Astrometry) facility at the VLT Interferometer on Cerro Paranal in Chile is expected to be fully operational in only a few years from now. With PRIMA/VLTI, it will then be possible to perform relative astrometry with an accuracy of the order of 10 microarcseconds over angles of about 10 arcseconds.(More)
ESO’s PRIMA (Phase-Referenced Imaging and Micro-arcsecond Astrometry) facility at the VLT Interferometer on Cerro Paranal in Chile is expected to be fully operational in only a couple of years from now. With PRIMA/VLTI, it will then be possible to perform relative astrometry with an accuracy of the order of 10 μas over angles of about 10. The main science(More)
We present preliminary results on the radial velocity follow-up of a planetary transit candidate (P=2.43d, V=15.4 mag) detected during the MA-CHO project. The photometry is consistent with a grazing transit of an object with radius ≥1.8R J orbiting a K dwarf star, and is the brightest best candidate detected from MACHO. Results from the 2.2m MPG/ESO(More)
With observations of the EP Cru system, we continue our series of measurements of spin-orbit angles in eclipsing binary star systems, the BANANA project (Binaries Are Not Always Neatly Aligned). We find a close alignment between the sky projections of the rotational and orbital angular momentum vectors for both stars (βp = −1.8± 1.6◦ and |βs| < 17◦). We(More)
As part of the BANANA project (Binaries Are Not Always Neatly Aligned), we have found that the eclipsing binary CV Velorum has misaligned rotation axes. Based on our analysis of the Rossiter-McLaughlin effect, we find sky-projected spin-orbit angles of βp = −52± 6◦ and βs = 3± 7◦ for the primary and secondary stars (B2.5V + B2.5V, P = 6.9 d). We combine(More)