Search Publications
The Age Dependence of Mid-infrared Emission around Young Star Clusters
Calzetti, Daniela; Lin, Zesen; Kong, Xu +9 more
Using the star cluster catalogs from the Hubble Space Telescope program Legacy Extragalactic UV survey (LEGUS) and 8 µm images from the IRAC camera on the Spitzer Space Telescope for five galaxies within 5 Mpc, we investigate how the 8 µm dust luminosity correlates with the stellar age on the 30-50 pc scale of star-forming regions. We …
CS Cha B: A disc-obscured M-type star mimicking a polarised planetary companion
Snellen, I. A. G.; Ginski, C.; Girard, J. +6 more
Context. Direct imaging provides a steady flow of newly discovered giant planets and brown dwarf companions. These multi-object systems can provide information about the formation of low-mass companions in wide orbits and/or help us to speculate about possible migration scenarios. Accurate classification of companions is crucial for testing format…
APEX observations of ortho-H2D+ towards dense cores in the Orion B9 filament
Miettinen, O.
Context. Initial conditions and very early stages of star formation can be probed through spectroscopic observations of deuterated molecular species
Aims: We aim to determine the ortho-H2D+ properties (e.g. column density and fractional abundance with respect to H2) in a sample of dense cores in the Orion B9 s…
Foreshock Cavities at Venus and Mars
Zhang, Tielong; Futaana, Yoshifumi; Frahm, Rudy +7 more
"Foreshock cavities" are regions of turbulent and heated solar wind plasma that form upstream of Earth's bow shock. Despite being common at Earth, none have yet been reported at other planets. Here we present a survey of events encountered by the ESA Venus Express spacecraft consistent with foreshock cavities at Venus and a case study of a foresho…
First results from MFOSC-P: low-resolution optical spectroscopy of a sample of M dwarfs within 100 parsecs
Homeier, D.; Allard, F.; Kumar, Vipin +4 more
Mt Abu Faint Object Spectrograph and Camera (MFOSC-P) is an in-house-developed instrument for the Physical Research Laboratory (PRL) 1.2 m telescope at Mt Abu, India, commissioned in 2019 February. Here we present the first science results derived from the low-resolution spectroscopy programme of a sample of M dwarfs carried out during the commiss…
Seasonal and Hemispheric Asymmetries of F Region Polar Cap Plasma Density: Swarm and CHAMP Observations
Reistad, J. P.; Laundal, K. M.; Haaland, S. +6 more
One of the primary mechanisms of loss of Earth's atmosphere is the persistent "cold" (T≲ 20 eV) ion outflow that has been observed in the magnetospheric lobes over large volumes with dimensions of order several Earth radii. As the main source of this cold ion outflow, the polar cap F region ionosphere and conditions within it have a disproportiona…
Gaia18aen: First symbiotic star discovered by Gaia
Reichart, D. E.; Skowron, J.; Gromadzki, M. +20 more
Context. Besides the astrometric mission of the Gaia satellite, its repeated and high-precision measurements also serve as an all-sky photometric transient survey. The sudden brightenings of the sources are published as Gaia Photometric Science Alerts and are made publicly available, allowing the community to photometrically and spectroscopically …
SDSS J124043.01+671034.68: the partially burned remnant of a low-mass white dwarf that underwent thermonuclear ignition?
Kepler, S. O.; Raddi, Roberto; Gänsicke, Boris T. +2 more
The white dwarf SDSS J124043.01+671034.68 (SDSS J1240+6710) was previously found to have an oxygen-dominated atmosphere with significant traces of neon, magnesium, and silicon. A possible origin via a violent late thermal pulse or binary interactions has been suggested to explain this very unusual photospheric composition. We report the additional…
Multispectral surface emissivity from VIRTIS on Venus Express
Tsang, C. C. C.; Mueller, N. T.; Smrekar, S. E.
The surface composition of Venus is mostly inaccessible to remote observation due to the dense cloud cover. There are five spectral windows that show measurable thermal emission from the surface at night. The VIRTIS spectrometer on Venus Express observed three of these windows over much of the southern hemisphere of Venus. We use these data along …
Photometric and Spectroscopic Studies of Superoutbursts of Three Dwarf Novae Independently Identified by the SVOM/GWAC System in 2018
Zheng, W.; Filippenko, A. V.; Xu, Y. +27 more
We report our photometric and spectroscopic follow-up observations of the superoutbursts of three dwarf novae (DNe; GWAC 180415A, GWAC 181017A, and GWAC 181211A) identified independently by the Ground Wide-angle Cameras system, one of the ground-based instruments of the China-France SVOM mission. Based on a combination of our photometry and that t…