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Automatic Tracking of Active Regions and Detection of Solar Flares in Solar EUV Images
Caballero, C.; Aranda, M. C.
Solar catalogs are frequently handmade by experts using a manual approach or semi-automated approach. The appearance of new tools is very useful because the work is automated. Nowadays it is impossible to produce solar catalogs using these methods, because of the emergence of new spacecraft that provide a huge amount of information. In this articl…
Orphan penumbrae: Submerging horizontal fields
Bellot Rubio, L. R.; Jurčák, J.; Sobotka, M.
Aims: We investigate the properties of orphan penumbrae, which are photospheric filamentary structures observed in active regions near polarity inversion lines that resemble the penumbra of regular sunspots but are not connected to any umbra.
Methods: We use Hinode data from the Solar Optical Telescope to determine the properties of orph…
Emission Measure Distribution for Diffuse Regions in Solar Active Regions
Tripathi, Durgesh; Mason, Helen E.; Klimchuk, James A. +1 more
Our knowledge of the diffuse emission that encompasses active regions is very limited. In this paper we investigate two off-limb active regions, namely, AR 10939 and AR 10961, to probe the underlying heating mechanisms. For this purpose, we have used spectral observations from Hinode/EIS and employed the emission measure (EM) technique to obtain t…
The evolving spectrum of the planetary nebula Hen 2-260
Zijlstra, A. A.; van Hoof, P. A. M.; Hajduk, M. +3 more
Aims: We analysed the planetary nebula Hen 2-260 using optical spectroscopy and photometry. We compared our observations with the data from literature to search for evolutionary changes. We also searched for photomertic variability of the central star.
Methods: The object Hen 2-260 was observed with the SAAO 1.0 m telescope (photometry) …
Dayside/nightside asymmetry of ion densities and velocities in Saturn's inner magnetosphere
Wahlund, J. -E.; Morooka, M. W.; Holmberg, M. K. G.
We present Radio and Plasma Wave Science Langmuir probe measurements from 129 Cassini orbits, which show a day/night asymmetry in both ion density and ion velocity in the radial region 4-6 RS (1 RS = 60,268 km) from the center of Saturn. The ion densities ni vary from an average of ∼35 cm-3 around noon u…
The candidate luminous blue variable G79.29+0.46: a comprehensive study of its ejecta through a multiwavelength analysis
Umana, G.; Agliozzo, C.; Noriega-Crespo, A. +5 more
We present a multiwavelength analysis of the nebula around the candidate luminous blue variable G79.29+0.46. The study is based on our radio observations performed at the Expanded Very Large Array and at the Green Bank Telescope and on archival infrared data sets, including recent images obtained by the Herschel Space Observatory. We confirm that …
CLASH: Extending Galaxy Strong Lensing to Small Physical Scales with Distant Sources Highly Magnified by Galaxy Cluster Members
Infante, L.; Zheng, W.; Molino, A. +35 more
We present a complex strong lensing system in which a double source is imaged five times by two early-type galaxies. We take advantage in this target of the extraordinary multi-band photometric data set obtained as part of the Cluster Lensing And Supernova survey with Hubble (CLASH) program, complemented by the spectroscopic measurements of the VL…
A state-of-the-art analysis of the dwarf irregular galaxy NGC 6822
Hidalgo, S. L.; Bono, G.; Pietrinferni, A. +5 more
We present a detailed photometric study of the dwarf irregular galaxy NGC 6822 aimed at investigating the properties of its stellar populations and, in particular, the presence of stellar radial gradients. Our goal is to analyse the stellar populations in six fields, which cover the whole bar of this dwarf galaxy. We derived the quantitative star …
Wavevector anisotropy of plasma turbulence at ion kinetic scales: solar wind observations and hybrid simulations
Narita, Y.; Motschmann, U.; Comişel, H.
Wavevector anisotropy of ion-scale plasma turbulence is studied at various values of ion beta. Two complementary methods are used. One is multi-point measurements of magnetic field in the near-Earth solar wind as provided by the Cluster spacecraft mission, and the other is hybrid numerical simulation of two-dimensional plasma turbulence. Both meth…
IP Eridani: A surprising long-period binary system hosting a He white dwarf
Jorissen, A.; Masseron, T.; Van Winckel, H. +3 more
We determine the orbital elements for the K0 IV + white dwarf (WD) system IP Eri, which appears to have a surprisingly long period of 1071 d and a significant eccentricity of 0.25. Previous spectroscopic analyses of the WD, based on a distance of 101 pc inferred from its Hipparcos parallax, yielded a mass of only 0.43 M⊙, implying it to…