Search Publications
Upper limits on CH3OH in the HD 163296 protoplanetary disk. Evidence for a low gas-phase CH3OH-to-H2CO ratio
Carpenter, J. M.; Walsh, C.; Hogerheijde, M. R. +6 more
Context. Methanol (CH3OH) is at the root of organic ice chemistry in protoplanetary disks. Its connection to prebiotic chemistry and its role in the chemical environment of the disk midplane make it an important target for disk chemistry studies. However, its weak emission has made detections difficult. To date, gas-phase CH3…
HD 2685 b: a hot Jupiter orbiting an early F-type star detected by TESS
Henning, Thomas; Vanderburg, Andrew; Latham, David W. +50 more
We report on the confirmation of a transiting giant planet around the relatively hot (Teff = 6801 ± 76 K) star HD 2685, whose transit signal was detected in Sector 1 data of NASA's TESS mission. We confirmed the planetary nature of the transit signal using Doppler velocimetric measurements with CHIRON, CORALIE, and FEROS, as well as usi…
Carbon-rich (DQ) white dwarfs in the Sloan Digital Sky Survey
Kepler, S. O.; Koester, D.
Context. Among the spectroscopically identified white dwarfs, a fraction smaller than 2% have spectra dominated by carbon lines, mainly molecular C2, but also a smaller group dominated by C I and C II lines. These are together called DQ white dwarfs.
Aims: We want to derive atmospheric parameters Teff, log g, and carbon …
Carbon depletion observed inside T Tauri inner rims. Formation of icy, kilometer size planetesimals by 1 Myr
McClure, M. K.
Context. The carbon content of protoplanetary disks is an important parameter to characterize planets formed at different disk radii. There is some evidence from far-infrared and submillimeter observations that gas in the outer disk is depleted in carbon, with a corresponding enhancement of carbon-rich ices at the disk midplane. Observations of th…
Three-dimensional modeling of chromospheric spectral lines in a simulated active region
Cheung, Mark C. M.; Rempel, Matthias; Danilovic, Sanja +4 more
Context. Because of the complex physics that governs the formation of chromospheric lines, interpretation of solar chromospheric observations is difficult. The origin and characteristics of many chromospheric features are, because of this, unresolved.
Aims: We focus on studying two prominent features: long fibrils and flare ribbons. To model …
The EREBOS project: Investigating the effect of substellar and low-mass stellar companions on late stellar evolution. Survey, target selection, and atmospheric parameters
Geier, S.; Dreizler, S.; Heber, U. +14 more
Eclipsing post-common-envelope binaries are highly important for resolving the poorly understood, very short-lived common-envelope phase of stellar evolution. Most hot subdwarfs (sdO/Bs) are the bare helium-burning cores of red giants that have lost almost all of their hydrogen envelope. This mass loss is often triggered by common-envelope interac…
Carbon and oxygen in metal-poor halo stars
Asplund, M.; Amarsi, A. M.; Nissen, P. E. +2 more
Carbon and oxygen are key tracers of the Galactic chemical evolution; in particular, a reported upturn in [C/O] towards decreasing [O/H] in metal-poor halo stars could be a signature of nucleosynthesis by massive Population III stars. We reanalyse carbon, oxygen, and iron abundances in 39 metal-poor turn-off stars. For the first time, we take into…
Evidence for ram-pressure stripping in a cluster of galaxies at z = 0.7
Pointecouteau, E.; Boselli, A.; Brinchmann, J. +10 more
Multi-Unit Spectroscopic Explorer (MUSE) observations of the cluster of galaxies CGr32 (M200 ≃ 2 × 1014 M⊙) at z = 0.73 reveal the presence of two massive star-forming galaxies with extended tails of diffuse gas detected in the [O II]λλ3727-3729 Å emission-line doublet. The tails, which have a cometary shape with a…
Planck's Dusty GEMS. VII. Atomic carbon and molecular gas in dusty starburst galaxies at z = 2 to 4
Kneissl, R.; Le Floc'h, E.; Omont, A. +5 more
The bright 3P1-3P0 ([CI] 1-0) and 3P2-3P1 ([CI] 2-1) lines of atomic carbon are becoming more and more widely employed as tracers of the cold neutral gas in high-redshift galaxies. Here we present observations of these lines in the 11 galaxies of the set of Pla…
The VLT-FLAMES Tarantula Survey. XXX. Red stragglers in the clusters Hodge 301 and SL 639
van Loon, J. Th.; Lennon, D. J.; Herrero, A. +10 more
Aims: We estimate physical parameters for the late-type massive stars observed as part of the VLT-FLAMES Tarantula Survey (VFTS) in the 30 Doradus region of the Large Magellanic Cloud (LMC).
Methods: The observational sample comprises 20 candidate red supergiants (RSGs) which are the reddest ((B - V) > 1 mag) and brightest (V < 16 …