Seminars

Subproject A04: The Most Metal-Poor Stars of the Galaxy

Subproject A04: The Most Metal-Poor Stars of the Galaxy

Norbert Christlieb (LSW), Hans-Günter Ludwig (LSW)

Our searches for the most metal-poor stars of the Galactic halo will be continued by means of a wide-angle sky survey currently being conducted with the Chinese LAMOST telescope, and using the low-resolution spectra acquired by the Gaia Blue Photometer. We will also carry out non-local thermodynamic equilibrium computations of molecular equilibrium and the populations of molecular energy levels, to derive corrections in particular for carbon abundances determined from CH molecular features.

Publications

Deshmukh, S. A.; Ludwig, H.-G.; Kučinskas, A.; Steffen, M.; Barklem, P. S.; Caffau, E.; Dobrovolskas, V.; Bonifacio, P.

The solar photospheric silicon abundance according to CO5BOLD: Investigating line broadening, magnetic fields, and model effects

12/2022 A&A 668, A48

Xylakis-Dornbusch, T.; Christlieb, N.; Lind, K.; Nordlander, T.

A method for identifying metal-poor stars with Gaia BP/RP spectra

10/2022 A&A 666, A58

Aoki, Wako; Li, Haining; Matsuno, Tadafumi; Xing, Qianfan; Chen, Yuqin; Christlieb, Norbert; Honda, Satoshi; Ishigaki, Miho N.; Shi, Jianrong; Suda, Takuma; Tominaga, Nozomu; Yan, Hong-Liang; Zhao, Jingkun; Zhao, Gang

Four-hundred Very Metal-poor Stars Studied with LAMOST and Subaru. I. Survey Design, Follow-up Program, and Binary Frequency

06/2022 ApJ 931, 146

Magg, Ekaterina; Bergemann, Maria; Serenelli, Aldo; Bautista, Manuel; Plez, Bertrand; Heiter, Ulrike; Gerber, Jeffrey M.; Ludwig, Hans-Günter; Basu, Sarbani; Ferguson, Jason W.; Gallego, Helena Carvajal; Gamrath, Sébastien; Palmeri, Patrick; Quinet, Pascal

Observational constraints on the origin of the elements. IV. Standard composition of the Sun

05/2022 A&A 661, A140

Bertran de Lis, S.; Prieto, Allende; Ludwig, H. -G.; Koesterke, L.

Interpolation of spectra from 3D model atmospheres

05/2022 A&A 661, A76

Cescutti, G.; Morossi, C.; Franchini, M.; Di Marcantonio, P.; Chiappini, C.; Steffen, M.; Valentini, M.; François, P.; Christlieb, N.; Cortés, C.; Kobayashi, C.; Depagne, E.

Barium lines in high-quality spectra of two metal-poor giants in the Galactic halo

10/2021 A&A 654, A164

Bonifacio, P.; Monaco, L.; Salvadori, S.; Caffau, E.; Spite, M.; Sbordone, L.; Spite, F.; Ludwig, H. -G.; Di Matteo, P.; Haywood, M.; François, P.; Koch-Hansen, A. J.; Christlieb, N.; Zaggia, S.

TOPoS. VI. The metal-weak tail of the metallicity distribution functions of the Milky Way and the Gaia-Sausage-Enceladus structure

07/2021 A&A 651, A79

Caffau, E.; Bonifacio, P.; Korotin, S. A.; François, P.; Lallement, R.; Matas Pinto, A. M.; Di Matteo, P.; Steffen, M.; Mucciarelli, A.; Katz, D.; Haywood, M.; Chemin, L.; Sartoretti, P.; Sbordone, L.; Andrievsky, S. M.; Kovtyukh, V. V.; Spite, M.; Spite, F.; Panuzzo, P.; Royer, F.; Thévenin, F.; Ludwig, H. -G.; Marchal, O.; Plum, G.

The Gaia RVS benchmark stars. I. Chemical inventory of the first sample of evolved stars and its Rb NLTE investigation

07/2021 A&A 651, A20

Cunningham, Tim; Tremblay, Pier-Emmanuel; Bauer, Evan B.; Toloza, Odette; Cukanovaite, Elena; Koester, Detlev; Farihi, Jay; Freytag, Bernd; Gänsicke, Boris T.; Ludwig, Hans-Günter; Veras, Dimitri

Horizontal spreading of planetary debris accreted by white dwarfs

05/2021 MNRAS 503, 1646

Dravins, Dainis; Ludwig, Hans-Günter; Freytag, Bernd

Spatially resolved spectroscopy across stellar surfaces. V. Observational prospects: toward Earth-like exoplanet detection

05/2021 A&A 649, A17

Dravins, Dainis; Ludwig, Hans-Günter; Freytag, Bernd

Spatially resolved spectroscopy across stellar surfaces. IV. F, G, and K-stars: Synthetic 3D spectra at hyper-high resolution

05/2021 A&A 649, A16

Cukanovaite, Elena; Tremblay, Pier-Emmanuel; Bergeron, Pierre; Freytag, Bernd; Ludwig, Hans-Günter; Steffen, Matthias

3D spectroscopic analysis of helium-line white dwarfs

03/2021 MNRAS 501, 5274

Lundkvist, Mia S.; Ludwig, Hans-Günter; Collet, Remo; Straus, Thomas

The signature of granulation in a solar power spectrum as seen with CO⁵BOLD

02/2021 MNRAS 501, 2512

Limberg, Guilherme; Rossi, Silvia; Beers, Timothy C.; Perottoni, Hélio D.; Pérez-Villegas, Angeles; Santucci, Rafael M.; Abuchaim, Yuri; Placco, Vinicius M.; Lee, Young Sun; Christlieb, Norbert; Norris, John E.; Bessell, Michael S.; Ryan, Sean G.; Wilhelm, Ronald; Rhee, Jaehyon; Frebel, Anna

Dynamically Tagged Groups of Very Metal-poor Halo Stars from the HK and Hamburg/ESO Surveys

01/2021 ApJ 907, 10

Karmakar, Subhajeet; Rajpurohit, A. S.; Allard, F.; Homeier, D.

Detection and characterization of two VLM binaries: LP 1033-31 and LP 877-72

07/2020 MNRAS 498, 737

Xiang, Mao-Sheng; Rix, Hans-Walter; Ting, Yuan-Sen; Ludwig, Hans-Günter; Coronado, Johanna; Zhang, Meng; Zhang, Hua-Wei; Buder, Sven; Tio, Piero Dal

Chemically Peculiar A and F Stars with Enhanced s-process and Iron-peak Elements: Stellar Radiative Acceleration at Work

07/2020 ApJ 898, 28

Rajpurohit, A. S.; Kumar, Vipin; Srivastava, Mudit K.; Allard, F.; Homeier, D.; Dixit, Vaibhav; Patel, Ankita

First results from MFOSC-P: low-resolution optical spectroscopy of a sample of M dwarfs within 100 parsecs

03/2020 MNRAS 492, 5844

Hanke, Michael; Hansen, Camilla Juul; Ludwig, Hans-Günter; Cristallo, Sergio; McWilliam, Andrew; Grebel, Eva K.; Piersanti, Luciano

A high-precision abundance analysis of the nuclear benchmark star HD 20

03/2020 A&A 635, A104

Hejazi, Neda; Lépine, Sébastien; Homeier, Derek; Rich, R. Michael; Shara, Michael M.

Chemical Properties of the Local Galactic Disk and Halo. I. Fundamental Properties of 1544 Nearby, High Proper-motion M Dwarfs and Subdwarfs

01/2020 AJ 159, 30

Cukanovaite, E.; Tremblay, P. -E.; Freytag, B.; Ludwig, H. -G.; Fontaine, G.; Brassard, P.; Toloza, O.; Koester, D.

Calibration of the mixing-length theory for structures of helium-dominated atmosphere white dwarfs

11/2019 MNRAS 490, 1010

Cunningham, Tim; Tremblay, Pier-Emmanuel; Freytag, Bernd; Ludwig, Hans-Günter; Koester, Detlev

Convective overshoot and macroscopic diffusion in pure-hydrogen-atmosphere white dwarfs

09/2019 MNRAS 488, 2503

González Hernández, J. I.; Bonifacio, P.; Caffau, E.; Ludwig, H. -G.; Steffen, M.; Monaco, L.; Cayrel, R.

The ⁶Li/⁷Li isotopic ratio in the metal-poor binary CS22876-032

08/2019 A&A 628, A111

Kaasinen, M.; Scoville, N.; Walter, F.; Da Cunha, E.; Popping, G.; Pavesi, R.; Darvish, B.; Casey, C. M.; Riechers, D. A.; Glover, S.

The Molecular Gas Reservoirs of z ∼ 2 Galaxies: A Comparison of CO(1−0) and Dust-based Molecular Gas Masses

07/2019 ApJ 880, 15

Pasquini, L.; Pala, A. F.; Ludwig, H. -G.; Lẽao, I. C.; de Medeiros, J. R.; Weiss, A.

Masses of the Hyades white dwarfs. A gravitational redshift measurement

07/2019 A&A 627, L8

Giribaldi, R. E.; Ubaldo-Melo, M. L.; Porto de Mello, G. F.; Pasquini, L.; Ludwig, H. -G.; Ulmer-Moll, S.; Lorenzo-Oliveira, D.

Accurate effective temperature from Hα profiles

04/2019 A&A 624, A10

Two-dimensional non-LTE O I 777 nm line formation in radiation hydrodynamics simulations of Cepheid atmospheres

04/2019 A&A 624, A85

Leão, I. C.; Pasquini, L.; Ludwig, H. -G.; de Medeiros, J. R.

Spectroscopic and astrometric radial velocities: Hyades as a benchmark

03/2019 MNRAS 483, 5026

Koch, Andreas; Reichert, Moritz; Hansen, Camilla Juul; Hampel, Melanie; Stancliffe, Richard J.; Karakas, Amanda; Arcones, Almudena

Unusual neutron-capture nucleosynthesis in a carbon-rich Galactic bulge star

02/2019 A&A 622, A159

Sonoi, T.; Ludwig, H. -G.; Dupret, M. -A.; Montalbán, J.; Samadi, R.; Belkacem, K.; Caffau, E.; Goupil, M. -J.

Calibration of mixing-length parameter α for MLT and FST models by matching with CO⁵BOLD models

01/2019 A&A 621, A84

Editor: G. Parmentier