Search Publications
Multiple Stellar Populations of Globular Clusters from Homogeneous Ca-CN-CH-NH Photometry. VI. M3 (NGC 5272) Is Not a Prototypical Normal Globular Cluster
Sneden, Christopher; Lee, Jae-Woo
We present Ca-CN-CH-NH photometry for the well-known globular cluster (GC) M3 (NGC 5272). We show new evidence for two M3 populations with distinctly different carbon and nitrogen abundances, seen in a sharp division between CN-weak and CN-strong red-giant branches (RGBs) in M3. The CN-strong population shows a C-N anticorrelation that is a natura…
Magnetic Fields of CP Stars in the Orion OB1 Association. V. Stars of Subgroups (c) and (d)
Romanyuk, I. I.; Semenko, E. A.; Moiseeva, A. V. +2 more
—The paper presents the results of magnetic field measurements of 27 chemically peculiar stars in subgroups (c) and (d) of the Orion OB1 association. In total, more than 140 circularly polarized spectra were obtained and measured in the period from 2013 to 2020. An analysis of the results showed that 13 out of 24 CP stars in subgroup (c) have a ma…
A MUSE spectro-imaging study of the Th 28 jet: Precession in the inner jet
Ray, T. P.; Eislöffel, J.; Bacciotti, F. +5 more
Context. Th 28 is a Classical T Tauri star in the Lupus 3 cloud that drives an extended bipolar jet. Previous studies of the inner jet identified signatures of rotation around the outflow axis, a key result for theories of jet launching. Thus this is an important source in which to investigate the poorly understood jet launching mechanism.
Ai…
Probing Protoplanetary Disk Winds with C II Absorption
Herczeg, Gregory J.; France, Kevin; Johns-Krull, Christopher M. +1 more
We present an analysis of wind absorption in the C II λ1335 doublet toward 40 classical T Tauri stars with archival far-ultraviolet (FUV) spectra obtained by the Hubble Space Telescope. Absorption features produced by fast or slow winds are commonly detected (36 out of 40 targets) in our sample. The wind velocity of the fast wind decreases with di…
Toward Precise Galaxy Evolution: A Comparison between Spectral Indices of z 1 Galaxies in the IllustrisTNG Simulation and the LEGA-C Survey
Bell, Eric F.; Maseda, Michael V.; Muzzin, Adam +13 more
We present the first comparison of observed stellar continuum spectra of high-redshift galaxies and mock galaxy spectra generated from hydrodynamical simulations. The mock spectra are produced from the IllustrisTNG TNG100 simulation combined with stellar population models and take into account dust attenuation and realistic observational effects (…
Observing and modelling the young solar analogue EK Draconis: starspot distribution, elemental abundances, and evolutionary status
Solanki, S. K.; Montes, D.; Hussain, G. A. J. +4 more
Observations and modelling of stars with near-solar masses in their early phases of evolution are critical for a better understanding of how dynamos of solar-type stars evolve. We examine the chemical composition and the spot distribution of the pre-main-sequence solar analogue EK Dra. Using spectra from the HERMES Spectrograph (La Palma), we obta…
Modeling of Possible Plume Mechanisms on Europa
Wurz, Peter; Vorburger, Audrey
Plumes spewing water high above Europa's surface have been inferred from several observation campaigns in the past decade. Whereas the occasional existence of plumes on Europa has thus been confirmed, the origin of the plumes remains uncertain. Most notably, it is still unclear whether the inferred plumes are of oceanic origin, possibly containing…
Convection and rotation boosted prescription of magnetic braking: application to the formation of extremely low-mass white dwarfs
Kepler, S. O.; Soethe, L. T. T.
Extremely low-mass white dwarfs (ELM WDs) are the result of binary evolution in which a low-mass donor star is stripped by its companion leaving behind a helium-core white dwarf (WD). We explore the formation of ELM WDs in binary systems considering the Convection And Rotation Boosted magnetic braking treatment. Our evolutionary sequences were cal…
A Deep Polarimetric Study of the Asymmetrical Debris Disk HD 106906
MacGregor, Meredith A.; Weinberger, Alycia J.; Debes, John H. +16 more
Located in the Lower Centaurus Crux group, HD 106906 is a young, binary stellar system. This system is unique among discovered systems in that it contains an asymmetrical debris disk, as well as an 11 MJup planet companion, at a separation of ~735 au. Only a handful of other systems are known to contain both a disk and a directly imaged…
Toward the true number of flaring giant stars in the Kepler field. Are their flaring specialities associated with their being giant stars?
Pál, A.; Günther, M. N.; Oláh, K. +4 more
Aims: We aim to give a reliable estimate of the number of flaring giant stars in the Kepler field. By analyzing the flaring activity of these stars, we explored their flare statistics and the released flare energies. The role of oscillation in suppressing magnetic activity was also investigated. We searched for flaring specialities that may b…