Search Publications
An empirical metallicity tracer in CEMP and C-normal stars
Hansen, C. J.; Reichert, M.; Singh, D. +2 more
Context. Deriving the metallicity, [Fe/H], in low-resolution spectra of carbon-enhanced metal-poor (CEMP) stars is a tedious task that, owing to the large number of line blends, often leads to uncertainties on [Fe/H] exceeding 0.25 dex. The CEMP stars increase in number with decreasing [Fe/H] and some of these are known to be bona fide second gene…
Census of the Young Stellar Population in the Galactic H II Region Sh2-242
Joshi, Santosh; Dutta, Somnath; Mondal, Soumen +3 more
We present here identification and characterization of the young stellar population associated with an active star-forming site Sh2-242. We used our own new optical imaging and spectroscopic observational data, as well as several archival catalogs, e.g., Pan-STARRS 1, Gaia DR2, IPHAS, Wide-field InfraRed Camera, 2MASS, and Spitzer. Slit spectrosco…
ALMA and NACO observations towards the young exoring transit system J1407 (V1400 Cen)
Hales, A.; van der Marel, N.; Min, M. +8 more
Aims: Our aim was to directly detect the thermal emission of the putative exoring system responsible for the complex deep transits observed in the light curve for the young Sco-Cen star 1SWASP J140747.93-394542.6 (V1400 Cen, hereafter J1407), confirming it as the occulter seen in May 2007, and to determine its orbital parameters with respect …
Pulsation and rotation in NGC 6811: the Kepler short-cadence stars
Rodríguez, E.; Martín-Ruiz, S.; Rodríguez-López, C. +3 more
We have analysed a selected sample of 36 Kepler short-cadence stars in the field of NGC 6811. The results reveal that all the targets are variable: two red giant stars with solar-like oscillations, 21 main-sequence pulsators (16 δ Scuti and five γ Doradus stars), and 13 rotating variables. Three new γ Doradus (γ Dor) variables (one is a hot γ Dor …
Light curve analysis of ground-based data from exoplanets transit database
Poro, A.; Davoudi, F.; Khakpash, S. +9 more
Photometric observations of exoplanet transits can be used to derive the orbital and physical parameters of an exoplanet. We analyzed several transit light curves of exoplanets that are suitable for ground-based observations whose complete information is available on the Exoplanet Transit Database (ETD). We analyzed transit data of planets includi…
Miscellaneous photometric variations in cataclysmic variables: V455 And, SS Cyg, AQ Men, LQ Peg, RW Tri and UX UMa
Bruch, Albert
Cataclysmic variables are among the photometrically most unstable star in the zoo of stellar objects, exhibiting light variations on all time-scales between millennia and seconds. The literature is full of reports on variable phenomena which often require independent confirmation before they can be accepted as established facts. In this contributi…
Organic matter in interstellar dust lost at the approach to the heliosphere. Exothermic chemical reactions of free radicals ignited by the Sun
Kimura, Hiroshi; Postberg, Frank; Altobelli, Nicolas +1 more
Aims: We tackle the conundrums of organic materials missing from interstellar dust when measured inside the Solar System, while undoubtedly existing in the local interstellar cloud (LIC), which surrounds the Solar System.
Methods: We present a theoretical argument that organic compounds sublimate almost instantaneously by exothermic reac…
Ionospheric total electron content of comet 67P/Churyumov-Gerasimenko
Henri, Pierre; Hajra, Rajkumar; Galand, Marina +6 more
We study the evolution of a cometary ionosphere, using approximately two years of plasma measurements by the Mutual Impedance Probe on board the Rosetta spacecraft monitoring comet 67P/Churyumov-Gerasimenko (67P) during August 2014-September 2016. The in situ plasma density measurements are utilized to estimate the altitude-integrated electron num…
Numerical simulation and data analysis of the 23 July 2012 SEP event observed by ACE, STEREO-A, and STEREO-B
Qin, G.; Qi, S. -Y.
An extremely powerful, superfast interplanetary coronal mass ejection (ICME) from the Sun on 23 July 2012 was detected by widely separated multiple spacecraft, namely STEREO-A, STEREO-B, and ACE, together with the ICME-driven shock and associated solar energetic particles (SEPs). We use the Parker spiral magnetic field model to analyze the relatio…
The Molecular Clouds Associated with the H II Regions/Candidates between L = 207°7 and L = 211°7
Wang, Hongchi; Ma, Yuehui; Zhang, Miaomiao +2 more
Using the PMO-13.7 m millimeter telescope at Delingha in China, we have conducted a large-scale simultaneous survey of 12CO, 13CO, and C18O J = 1 - 0 emission toward the sky region centered at l = 209°7, b = -2°25 with a coverage of 4°0 × 4°5. The majority of the emission in the region comes from the clouds with ve…