Presentation on theme: "HATSouth: a global network of automated telescopes to detect transiting exoplanets Luigi Mancini Max Planck Institute for Astronomy, Heidelberg."— Presentation transcript:
HATSouth: a global network of automated telescopes to detect transiting exoplanets Luigi Mancini Max Planck Institute for Astronomy, Heidelberg
HATSouth is a network of automated and homogeneous telescopes capable of year-round 24-hour monitoring of positions over an entire hemisphere of the sky. HATSouth employs six telescope units spread over three locations with large longitude separation in the southern hemisphere: Las Campanas Observatory - Chile, HESS site - Namibia, Siding Spring Observatory - Australia LCO HESS SSO HS1 HS2 HS3 HS4 HS5 HS6
Hat-South partners P ONTIFICIA U NIVERSIDAD C ATOLICA D E C HILE M AX P LANCK I NSTITUTE FOR A STRONOMY HESS S ITE, N AMIBIA S IDING S PRING O BSERVATORY, A USTRALIA L AS C AMPANAS, C HILE B. C. Addison G. A. Bakos (P.I.) D. Bayliss B. Beky R. Brahm L. Buchhave B. Csak P. Conroy Z. Csubry N. Espinoza J. D. Hartman T. Henning A. Jordan J. Lazar M. Mohler L. Mancini N. Nikolov R. W. Noyes K. Penev I. Papp M. Rabus D. D. Sasselov B. Schmidt P. Sari V. Suc C. G. Tinney D. J. Wright G. Zhou
Each of the three sites operates two HATSouth units. All HATS units are protected by a clamshell dome, and operate in a fully automated manner. Each unit holds on a common mount 4×18cm f/2.8 Takahashi astrographs, each incorporating an Apogee 4K×4K CCD detector with Sloan r filter. Each HATS unit has a mosaic field of view on the sky of 8°×8°, with a scale of 3.7’’ pixel -1. We observe 12 field per year. Technical details are reported in Bakos et al. PASP 2012, arXiv:1206.1391
The units and control buildings were installed at all three sites in 2009. The HATSouth control building at each of the sites hosts the computer system that is responsible for operating the instruments. We have four computers at each site; one control computer for each of the two HATS units, one node-computer, and a server for storing data. Each control computer manages an entire unit, including the dome, telescope mount, attached devices, and all four CCDs. The control computer performs real-time analysis of the images acquired, such as calibrations, astrometry, PSF analysis, focusing, and other tasks.
At each site an array of weather sensing devices are attached to the roof top of the control building. We continuously monitor the meteorological conditions at the sites with 30 second time resolution. Each of the six units has conducted observations on 500 nights over a two- year time period, yielding a total of more than 1 million science frames at 4-min integration time, and observing 10.65 hours per day on average. Photometric precision reaches ≈ 6 mmag at 4-min cadence for the brightest non-saturated stars at r ≈ 9
Light curves are extracted by aperture photometry with the IRAF task Daophot, and treated with External Parameter Decorrelation (Bakos et al. ApJ 670, 826, 2007) Trend Filtering Algorithm (Kovács et al. MNRAS 356, 557, 2005) Periodic transit signals are identified with the Box-fitting Least Squares technique (Kovács et al. AAP 391, 369, 2002). Promising transiting-planet candidates are then selected as HATSouth candidates. After the identification of a candidate, its host star undergoes spectral analysis, in order to estimate its RV variation, and photometric follow-up. Spectroscopic observations ANU 2.3mWiFeS,SSO Euler 1.2mCoralieLa Silla ESO 2.2mFEROSLa Silla NOT 2.56mFIESLa Palma AAT 3.9mCYCLOPSSSO Photometric observations ESO 2.2mGRONDLa Silla FTS 2.0mSSO Swope 1.0m LCO CTIO 0.9mCTIO
Light curves are extracted by aperture photometry with the IRAF task Daophot, and treated with External Parameter Decorrelation (Bakos et al. ApJ 670, 826, 2007) Trend Filtering Algorithm (Kovács et al. MNRAS 356, 557, 2005) Periodic transit signals are identified with the Box-fitting Least Squares technique (Kovács et al. AAP 391, 369, 2002). Promising candidates with planet like transits are then selected as HAT- South candidates.
Simulations indicate that for a single HATSouth field observed over two months the total expected planet yield is 2.9. Assuming 12 fields observed per year, we expect to find ≈30 transiting planets per year, including ≈1 planet per year with R 10 d (Bakos et al. PASP 2012).
Analysis of 10 fields have yielded: ≈ 300 candidates ≈ 30 good candidates 3 confirmed hot-Jupiter planets
HATS-1b HATS-1b is a transiting extrasolar planet orbiting around a moderately bright V=12.05 G dwarf star (M=0.99 M ⊙ and R=1.04 R ⊙ ). HATS-1b has P = 3.4465 d, M = 1.86 M J, R = 1.30 R J.
HATS-1b HATS-1b is a transiting extrasolar planet orbiting around a moderately brightV=12.05 G dwarf star (M=0.99 M ⊙ and R=1.04 R ⊙ ). HATS-1b has P = 3.4465 d, M = 1.86 M J, R = 1.30 R J. Penev et al. Astronomical Journal 2012, arXiv:1206.1524
Conclusions The HATSouth network with three sites and 24 telescopes is capable of continuously monitoring 128 square arc-degrees at celestial positions. The primary scientific goal of the network is to discover and characterize a large number of transiting extrasolar planets, reaching out to long periods and down to small planetary radii. So far we detected 3 hot-Jupiters and have a lot of candidates. Global networks of telescopes present a powerful way of studying time-variable astronomical phenomena.