2,626 research outputs found
The HATNet and HATSouth Exoplanet Surveys
The Hungarian-made Automated Telescope Network (HATNet) has been in operation
since 2003, with the key science goal being the discovery and accurate
characterization of transiting extrasolar planets (TEPs) around bright stars.
Using six small, 11\,cm\ aperture, fully automated telescopes in Arizona and
Hawaii, as of 2017 March, it has discovered and accurately characterized 67
such objects. The HATSouth network of telescopes has been in operation since
2009, using slightly larger, 18\,cm diameter optical tubes. It was the first
global network of telescopes using identical instrumentation. With three
premier sites spread out in longitude (Chile, Namibia, Australia), the HATSouth
network permits round-the-clock observations of a 128 square arcdegree swath of
the sky at any given time, weather permitting. As of this writing, HATSouth has
discovered 36 transiting exoplanets. Many of the altogether ~100 HAT and
HATSouth exoplanets were the first of their kind. They have been important
contributors to the rapidly developing field of exoplanets, motivating and
influencing observational techniques, theoretical studies, and also actively
shaping future instrumentation for the detection and characterization of such
objects.Comment: Invited review chapter, accepted for publication in "Handbook of
Exoplanets", edited by H.J. Deeg and J.A. Belmonte, Springer Reference Work
The rich frequency spectrum of the triple-mode variable AC And
Fourier analysis of the light curve of AC And from the HATNet database
reveals the rich frequency structure of this object. Above 30 components are
found down to the amplitude of 3 mmag. Several of these frequencies are not the
linear combinations of the three basic components. We detect period increase in
all three components that may lend support to the Pop I classification of this
variable.Comment: Poster presented at IAU Symposium 301, "Precision Asteroseismology -
Celebration of the Scientific Opus of Wojtek Dziembowski", 19-23 August 2013,
Wroclaw, Polan
HAT-P-12b: A Low-Density Sub-Saturn Mass Planet Transiting a Metal-Poor K Dwarf
We report on the discovery of HAT-P-12b, a transiting extrasolar planet
orbiting the moderately bright V=12.8 K4 dwarf GSC 03033-00706, with a period P
= 3.2130598 +- 0.0000021 d, transit epoch Tc = 2454419.19556 +- 0.00020 (BJD)
and transit duration 0.0974 +- 0.0006 d. The host star has a mass of 0.73 +-
0.02 Msun, radius of 0.70 +- ^0.02_0.01 Rsun, effective temperature 4650 +- 60
K and metallicity [Fe/H] = -0.29 +- 0.05. We find a slight correlation between
the observed spectral line bisector spans and the radial velocity, so we
consider, and rule out, various blend configurations including a blend with a
background eclipsing binary, and hierarchical triple systems where the
eclipsing body is a star or a planet. We conclude that a model consisting of a
single star with a transiting planet best fits the observations, and show that
a likely explanation for the apparent correlation is contamination from
scattered moonlight. Based on this model, the planetary companion has a mass of
0.211 +- 0.012 MJup, and a radius of 0.959 +- ^0.029_0.021 RJup yielding a mean
density of 0.295 +- 0.025 g cm^-3. Comparing these observations with recent
theoretical models we find that HAT-P-12b is consistent with a ~ 1-4.5 Gyr,
mildly irradiated, H/He dominated planet with a core mass Mc <~ 10 Mearth.
HAT-P-12b is thus the least massive H/He dominated gas giant planet found to
date. This record was previously held by Saturn.Comment: Accepted for publication in ApJ, 13 pages, 9 figures, 5 table
HAT-P-16b: A 4 Mj Planet Transiting A Bright Star On An Eccentric Orbit
We report the discovery of HAT-P-16b, a transiting extrasolar planet orbiting
the V = 10.8 mag F8 dwarf GSC 2792-01700, with a period P = 2.775960 +-
0.000003 d, transit epoch Tc = 2455027.59293 +- 0.00031 (BJD), and transit
duration 0.1276 +- 0.0013 d. The host star has a mass of 1.22 +- 0.04 Msun,
radius of 1.24 +- 0.05 Rsun, effective temperature 6158 +-80 K, and metallicity
[Fe/H] = +0.17 +- 0.08. The planetary companion has a mass of 4.193 +- 0.094
MJ, and radius of 1.289 +- 0.066 RJ yielding a mean density of 2.42 +- 0.35
g/cm3. Comparing these observed characteristics with recent theoretical models,
we find that HAT-P-16b is consistent with a 1 Gyr H/He-dominated gas giant
planet. HAT-P-16b resides in a sparsely populated region of the mass{radius
diagram and has a non-zero eccentricity of e = 0.036 with a significance of 10
sigma.Comment: Submitted to Ap
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