S. Castellini

Università degli Studi di Perugia, Perugia, Umbria, Italy

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Publications (7)6 Total impact

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    ABSTRACT: Context. Beating the Earth's day-night cycle is mandatory for long and continuous time-series photometry and had been achieved with either large ground-based networks of observatories at different geographic longitudes or when conducted from space. A third possibility is offered by a polar location with astronomically-qualified site characteristics. Aims. In this paper, we present the first scientific stellar time-series optical photometry from Dome C in Antarctica and analyze approximately 13,000 CCD frames taken in July 2007. Methods. The optical pilot telescope of the "International Robotic Antarctic Infrared Telescope", named "small IRAIT" (sIRAIT), and its UBV RI CCD photometer were used in BV R for a continuous 243 hours (10.15 days) with a duty cycle of 98% and a cadence of 155 sec. The prime targets were the chromospherically active, spotted binary star V841 Cen and the non-radially pulsating �-Scuti star V1034 Cen. Results. We confirm the known 0.2-day fundamental period of V1034 Cen and found a total of 23 further periods between 2.2 hours and 3.5 days. V841 Cen's V amplitude due to spots appeared to be at a record high of 0. m4 in V in July 2007. We present a spot-model analysis with a light-curve inversion technique and found the star with a spot filling factor of 44% of the visible hemisphere, among the highest ever measured values for active stars, and a temperature difference photosphere minus spot of 750±100 K. Its odd-numbered (for a single site) rotation period was determined with a higher precision than before (5.8854±0.0026 days) despite the comparably short data set. The rms scatter from a 2.4-hour data subset was 3 mmag in V and 4.2 mmag in R. The differential data quality is 3-4 times better than with the 25cm Fairborn Automatic Photoelectric Telescope in southern Arizona and is likely due to the exceptionally low scintillation noise at Dome C. Conclusions. We conclude that high-precision CCD photometry with exceptional time coverage and cadence can be obtained at Dome C in Antarctica and be successfully used for time-series astrophysics.
    Astronomy and Astrophysics 10/2008; 490:287-295. DOI:10.1051/0004-6361:200810379 · 4.48 Impact Factor
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    ABSTRACT: Beating the Earth's day-night cycle is mandatory for long and continuous time-series photometry and had been achieved with either large ground-based networks of observatories at different geographic longitudes or when conducted from space. A third possibility is offered by a polar location with astronomically-qualified site characteristics. Aims. In this paper, we present the first scientific stellar time-series optical photometry from Dome C in Antarctica and analyze approximately 13,000 CCD frames taken in July 2007. We conclude that high-precision CCD photometry with exceptional time coverage and cadence can be obtained at Dome C in Antarctica and be successfully used for time-series astrophysics. Comment: accepted for A&A
    EAS Publications Series 07/2008; DOI:10.1051/eas:0833037
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    ABSTRACT: Small IRAIT is a 25 cm Cassegrain telescope, installed at Dome C, on the high Antarctic plateau, during 2007 winter campaign. It performed a first test of multiband (UBVRI) photometry from Dome C, taking advantage of its remote control system that allowed a 10 days, 98% duty cycle run on a chromospherically active, spotted star in Cen (V841); it also tested multiband acquisition on open clusters, AGB stars, blazars (PKS2155), eclipsing binaries. In situ optimization made the telescope able to operate in the cold, harsh Antarctic environment.
    Proceedings of SPIE - The International Society for Optical Engineering 07/2008; DOI:10.1117/12.791908 · 0.20 Impact Factor
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    ABSTRACT: First time-series observations with the 25-cm sIRAIT Antarctic pilot telescope from May 2007 are presented and show that the site is well suited for time-series high-precision photometry. Our target stars were one spotted 5.998-day rotating variable and one short-period delta-Scuti star. A total of 13 000 BVR CCD frames covered a time series of 243 consecutive hours.
    EAS Publications Series; 01/2008
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    ABSTRACT: This article reviews the situation for robotization of telescopes and instruments at the Antarctic station Concordia on Dome C. A brain-storming meeting was held in Tenerife in March 2007 from which this review emerged.We describe and summarize the challenges for night-time operations of various astronomical experiments at conditions “between Earth and Space” and conclude that robotization is likely a prerequisite for continuous astronomical data taking during the 2000-hour night at Dome C. (© 2007 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)
    Astronomische Nachrichten 06/2007; 328(6):451 - 474. DOI:10.1002/asna.200710780 · 1.12 Impact Factor
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    ABSTRACT: Small IRAIT is a 25 cm telescope planned to be installed at Dome C during February 2007. It will be equipped with a CCD, a filter wheel, two photomultipliers and a liquid crystal tunable filter. Small IRAIT is intended to: test astronomical measurements from Dome C; provide site qualification and suitability for asteroseismology by taking advantage of the low scintillation level and the possibility for long uninterrupted observations. Small IRAIT will be the forerunner of the IRAIT telescope that will be installed during the Antarctic Summer 2007-2008.
    Communications in Asteroseismology 05/2007; 150:315. DOI:10.1553/cia150s315
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    ABSTRACT: Thanks to exceptional coldness, low sky brightness and low content of water vapour of the above atmosphere Dome C, one of the three highest peaks of the large Antarctic plateau, is likely to be the best site on Earth for thermal infrared observations (2.3-300 μm) as well as for the far infrared range (30 μm-1mm). IRAIT (International Robotic Antarctic Infrared Telescope) will be the first European Infrared telescope operating at Dome C. It will be delivered to Antarctica at the end of 2006, will reach Dome C at the end of 2007 and the first winter-over operation will start in spring 2008. IRAIT will offer a unique opportunity for astronomers to test and verify the astronomical quality of the site and it will be a useful test-instrument for a new generation of Antarctic telescopes and focal plane instrumentations. We give here a general overview of the project and of the logistics and transportation options adopted to facilitate the installation of IRAIT at Dome C. We summarize the results of the electrical, electronics and networking tests and of the sky polarization measurements carried out at Dome C during the 2005-2006 summer-campaign. We also present the 25 cm optical telescope (small-IRAIT project) that will installed at Dome C during the Antarctic summer 2006-2007 and that will start observations during the 2007 Antarctic winter when a member of the IRAIT collaboration will join the Italian-French Dome C winter-over team.
    Proceedings of SPIE - The International Society for Optical Engineering 07/2006; 6267(1):62671H. DOI:10.1117/12.670302 · 0.20 Impact Factor