We report the discovery of two transiting extrasolar planets by the HATSouth survey. HATS-9b orbits an old (10.8 + or - 1.5 Gyr) V = 13.3 G dwarf star with a period P approximately 1.9153 days. The ...host star has a mass of 1.03 M sub(odot), radius of 1.503 Rodot, and effective temperature 5366 + or - 70 K. The planetary companion has a mass of 0.837 M sub(J) and radius of 1.065 R sub(J), yielding a mean density of 0.85 g cm super(-3). HATS-10b orbits a V = 13.1 G dwarf star with a period P approximately 3.3128 days. The host star has a mass of 1.1 M sub(odot), radius of 1.11 R sub(odot), and effective temperature 5880 + or - 120 K. The planetary companion has a mass of 0.53 M sub(J) and radius of 0.97 R sub(J), yielding a mean density of 0.7 g cm super(-3). Both planets are compact in comparison with planets receiving similar irradiation from their host stars and lie in the nominal coordinates of Field 7 of K2, but only HATS-9b falls on working silicon. Future characterization of HATS-9b with the exquisite photometric precision of the Kepler telescope may provide measurements of its reflected light signature.
Abstract
We report the discovery of two transiting Neptunes by the HATSouth survey. The planet HATS-37Ab has a mass of
(31.5 ± 13.4
M
⊕
) and a radius of
, and is on a
day orbit around a
mag,
star ...with a radius of
. We also present evidence that the star HATS-37A has an unresolved stellar companion HATS-37B, with a photometrically estimated mass of
. The planet HATS-38b has a mass of
(23.5 ± 3.5
M
⊕
) and a radius of
, and is on a
day orbit around a
mag,
star with a radius of
. Both systems appear to be old, with isochrone-based ages of
Gyr, and
Gyr, respectively. Both HATS-37Ab and HATS-38b lie in the Neptune desert and are thus examples of a population with a low occurrence rate. They are also among the lowest-mass planets found from ground-based wide-field surveys to date.
We report the discovery of HATS-1b, a transiting extrasolar planet orbiting the moderately bright V = 12.05 G dwarf star GSC 6652-00186, and the first planet discovered by HATSouth, a global network ...of autonomous wide-field telescopes. HATS-1b has a period of P approximately 3.4465 days, mass of M sub(p) approximately 1.86 M sub(J), and radius of R sub(p) approximately 1.30 R sub(J). The host star has a mass of 0.99 M sub(odot) and radius of 1.04 R sub(odot). The discovery light curve of HATS-1b has near-continuous coverage over several multi-day timespans, demonstrating the power of using a global network of telescopes to discover transiting planets.
We report the discovery by the HATSouth network of HATS-7b, a transiting Super-Neptune with a mass of 0.120 + or - 0.012 MsubJ, a radius of 0.563 + 0.046 - 0.034 RsubJ, and an orbital period of ...3.1853 days. The host star is a moderately bright K dwarf star with a mass of 0.849 + or - 0.027 MsubS, a radius of 0.815 + 0.049 - 0.035 RsubS, and a metallicity of Fe/H= +0.250 + or - 0.080. HATS-7b, which, together with the recently discovered HATS-8b, is one of the first two transiting Neptunes discovered in the Southern sky, is a prime target for additional follow-up observations with southern hemisphere facilities to characterize the atmospheres of super-Neptunes.
We report the discovery of HATS-71b, a transiting gas giant planet on a day orbit around a mag M3 dwarf star. HATS-71 is the coolest M dwarf star known to host a hot Jupiter. The loss of light during ...transits is 4.7%, more than in any other confirmed transiting planet system. The planet was identified as a candidate by the ground-based HATSouth transit survey. It was confirmed using ground-based photometry, spectroscopy, and imaging, as well as space-based photometry from the NASA Transiting Exoplanet Survey Satellite mission (TIC 234523599). Combining all of these data, and utilizing Gaia DR2, we find that the planet has a radius of and mass of (95% confidence upper limit of ), while the star has a mass of and a radius of .
Methylthymol blue in Fricke gels Penev, K I; Mequanint, K
Journal of physics. Conference series,
01/2015, Letnik:
573, Številka:
1
Journal Article
Recenzirano
Odprti dostop
The initial trial of methylthymol blue (MTB) as a chelator for ferric iron in Fricke gel dosimeters, used for three-dimensional (3D) dosimetry in cancer radiotherapy, is reported. MTB is a structural ...analogue of the conventionally used xylenol orange (XO); however, the absorbance spectrum of the ferric-MTB complex is shifted to higher wavelengths, which should allow for lower amount of light scattering during gel scanning. In this study, two gelatin substrates, two sources of XO and one source of MTB have been compared. The MTB- containing gels exhibited similar dose response and diffusion coefficient to the XO-containing gels at their wavelengths of maximum absorption (620 and 585 nm, respectively). In addition, the MTB gels gave an excellent dose response at 633 nm, which is an important wavelength that is already used with other 3D dosimeters.
We report the discovery of two transiting extrasolar planets from the HATSouth survey. HATS-11, a V= 14.1 G0-star shows a periodic 12.9 mmag dip in its light curve every 3.6192 days and a radial ...velocity variation consistent with a Keplerian orbit. HATS-11 has a mass of 1.000 + or - 0.060 M sub(middot in circle), a radius of 1.444 + or - 0.057 R sub(middot in circle) and an effective temperature of 6060 + or - 150 K, while its companion is a 0.85+ or - 0.12 M sub(J), 1.510 + or - 0.078 R sub(J) planet in a circular orbit. HATS-12 shows a periodic 5.1 mmag flux decrease every 3.1428 days and Keplerian RV variations around a V= 12.8 F-star. HATS-12 has a mass of 1.489 +or- 0.071 M sub(middot in circle), a radius of 2.21+ or -0.21 R sub(middot in circle), and an effective temperature of 6408 + or - 75 K. For HATS-12b, our measurements indicate that this is a 2.38 + or - 0.11M sub(J), 1.35 + or - 0.17 R sub(J) planet in a circular orbit. Both host stars show subsolar metallicities of -0.390 + or - 0.060 dex and -0.100 + or - 0.040 dex, respectively, and are (slightly) evolved stars. In fact, HATS-11 is among the most metal-poor and, HATS-12, with a log gmow * of 3.923 + or - 0.065, is among the most evolved stars hosting a hot-Jupiter planet. Importantly, HATS-11 and HATS-12 have been observed in long cadence by Kepler as part of K2 campaign 7 (EPIC216414930 and EPIC218131080 respectively).
High-precision photometry for K2 Campaign 1 Huang, C. X; Penev, K; Hartman, J. D ...
Monthly notices of the Royal Astronomical Society,
12/2015, Letnik:
454, Številka:
4
Journal Article
Recenzirano
The two reaction wheel K2 mission promises and has delivered new discoveries in the stellar and exoplanet fields. However, due to the loss of accurate pointing, it also brings new challenges for the ...data reduction processes. In this paper, we describe a new reduction pipeline for extracting high-precision photometry from the K2 data set, and present public light curves for the K2 Campaign 1 target pixel data set. Key to our reduction is the derivation of global astrometric solutions from the target stamps, from which accurate centroids are passed on for high-precision photometry extraction. We extract target light curves for sources from a combined UCAC4 and EPIC catalogue – this includes not only primary targets of the K2 campaign 1, but also any other stars that happen to fall on the pixel stamps. We provide the raw light curves, and the products of various detrending processes aimed at removing different types of systematics. Our astrometric solutions achieve a median residual of ∼0.127 arcsec. For bright stars, our best 6.5 h precision for raw light curves is ∼20 parts per million (ppm). For our detrended light curves, the best 6.5 h precision achieved is ∼15 ppm. We show that our detrended light curves have fewer systematic effects (or trends, or red-noise) than light curves produced by other groups from the same observations. Example light curves of transiting planets and a Cepheid variable candidate, are also presented. We make all light curves public, including the raw and detrended photometry, at http://k2.hatsurveys.org.
Context.
The transiting exoplanetary system WASP-174 was reported to be composed by a main-sequence F star (
V
= 11.8 mag) and a giant planet, WASP-174b (orbital period
P
orb
= 4.23 days). However ...only an upper limit was placed on the planet mass (<1.3
M
Jup
), and a highly uncertain planetary radius (0.7−1.7
R
Jup
) was determined.
Aims.
We aim to better characterise both the star and the planet and precisely measure their orbital and physical parameters.
Methods.
In order to constrain the mass of the planet, we obtained new measurements of the radial velocity of the star and joined them with those from the discovery paper. Photometric data from the HATSouth survey and new multi-band, high-quality (precision reached up to 0.37 mmag) photometric follow-up observations of transit events were acquired and analysed for getting accurate photometric parameters. We fit the model to all the observations, including data from the TESS space telescope, in two different modes: incorporating the stellar isochrones into the fit, and using an empirical method to get the stellar parameters. The two modes resulted to be consistent with each other to within 2
σ
.
Results.
We confirm the grazing nature of the WASP-174b transits with a confidence level greater than 5
σ
, which is also corroborated by simultaneously observing the transit through four optical bands and noting how the transit depth changes due to the limb-darkening effect. We estimate that ≈76% of the disk of the planet actually eclipses the parent star at mid-transit of its transit events. We find that WASP-174b is a highly-inflated hot giant planet with a mass of
M
p
= 0.330 ± 0.091
M
Jup
and a radius of
R
p
= 1.435 ± 0.050
R
Jup
, and is therefore a good target for transmission-spectroscopy observations. With a density of
ρ
p
= 0.135 ± 0.042 g cm
−3
, it is amongst the lowest-density planets ever discovered with precisely measured mass and radius.
We report the discovery of HATS-17b, the first transiting warm Jupiter of the HATSouth network. HATS-17b transits its bright (V= 12.4) G-type (Mlow * = 1.131 + or - 0.030 M sub(middot in circle), ...Rlow * = (ProQuest: Formulae and/or non-USASCII text omitted) R sub(middot in circle)) metal-rich (Fe/H = +0.3 dex) host star in a circular orbit with a period of P= 16.2546 days. HATS-17b has a very compact radius of 0.777 + or - 0.056 R sub(J) given its Jupiter-like mass of 1.338 + or - 0.065 M sub(J). Up to 50% of the mass of HATS-17b may be composed of heavy elements in order to explain its high density with current models of planetary structure. HATS-17b is the longest period transiting planet discovered to date by a ground-based photometric survey, and is one of the brightest transiting warm Jupiter systems known. The brightness of HATS-17 will allow detailed follow-up observations to characterize the orbital geometry of the system and the atmosphere of the planet.
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