311 citations · 740 across the 18 of their papers we have counts for
19 papers
Analysis of the possible satellite contamination in LAMOST-MRS spectra
Mikhail Kovalev, Olivier R. Hainaut, Xuefei Chen +1
We present the detection of false positive double-lined spectroscopic binaries candidates (SB2) using medium-resolution survey (MRS) spectra from the one time-domain field of LAMOS…
The orbits of outer planetary satellites using the Gaia data
Nikolay V. Emelyanov, Mikhail Kovalev, Maxim I. Varfolomeev
Launch of the Gaia space observatory started a new era in astrometry when the accuracy of star coordinates increased by thousands of times. Significant improvement of accuracy was…
Test of binary spectral model on FEROS spectra. First estimation of the fundamental parameters for HD 20784
Mikhail Kovalev, Sarah Gebruers, Ilya Straumit
We analyse spectra of 26 early-type stars, with suspected binarity, using a binary spectral model adapted for high-resolution FEROS spectra. We confirm seven SB2 candidates (AE Pic…
Fundamental parameters for dEB SB2 binary system J064726.39+223431.6
Mikhail Kovalev, Song Wang, Xuefei Chen +1
We present a study of eclipsing binary J064726.39+223431.6 using spectra from the LAMOST-MRS and TESS photometry. We use full-spectrum fitting to derive radial velocities and spect…
Detection of 2460 SB2 candidates in the LAMOST-MRS, using projected rotational velocities and a binary spectral model
Mikhail Kovalev, Chen Xuefei, Han Zhanwen
We present a new method for the detection of double-lined spectroscopic binaries (SB2) using values from spectral fits. The method is tested on synthetic and real spectr…
TYC~2990-127-1: an Algol-type SB2 binary system of subgiant and red giant with a probable ongoing mass-transfer
Mikhail Kovalev, Zhenwei Li, Xiaobin Zhang +3
We present a study of the spectroscopic binary TYC 2990-127-1 from the LAMOST survey. We use full-spectrum fitting to derive radial velocities and spectral parameters. The high mas…
The SAPP pipeline for the determination of stellar abundances and atmospheric parameters of stars in the core program of the PLATO mission
Matthew Raymond Gent, Maria Bergemann, Aldo Serenelli +25
We introduce the SAPP (Stellar Abundances and atmospheric Parameters Pipeline), the prototype of the code that will be used to determine parameters of stars observed within the cor…
LAMOST Time-Domain Survey: First Results of four 2 plates
Song Wang, Haotong Zhang, Zhongrui Bai +23
From Oct. 2019 to Apr. 2020, LAMOST performs a time-domain spectroscopic survey of four 2 plates with both low- and med-resolution observations. The low-resolution spectroscopic…
Double-lined spectroscopic binaries in M11
Mikhail Kovalev, Ilya Straumit
We have developed a new method for spectral analysis of binaries. Our method successfully identifies SB2 candidates from high-resolution Gaia-ESO spectra. Compared to the commonly…
Analysis of Red-Supergiants in VdBH 222
Randa Asa'd, M. Kovalev, B. Davies +6
Recent surveys uncovered new Young Massive Clusters (YMCs) that host dozens of Red Supergiants (RSGs) in the inner Milky Way. These clusters are ideal for studying the most recent…
Evidence for Sub-Chandrasekhar Type Ia Supernovae from Stellar Abundances in Dwarf Galaxies
Evan N. Kirby, Justin L. Xie, Rachel Guo +6
There is no consensus on the progenitors of Type Ia supernovae (SNe Ia) despite their importance for cosmology and chemical evolution. We address this question by using our previou…
NLTE Chemical abundances in Galactic open and globular clusters
Mikhail Kovalev, Maria Bergemann, Yuan-Sen Ting +1
Aims We study the effects of non-local thermodynamic equilibrium (NLTE) on the determination of stellar parameters and abundances of Fe, Mg, and Ti from the medium-resolution spect…
Catalog of Chromium, Cobalt, and Nickel Abundances in Globular Clusters and Dwarf Galaxies
Evan N. Kirby, Justin L. Xie, Rachel Guo +2
We present measurements of the abundances of chromium, cobalt, and nickel in 4113 red giants, including 2277 stars in globular clusters, 1820 stars in the Milky Way's dwarf satelli…
4MOST Consortium Survey 4: Milky Way Disc and Bulge High-Resolution Survey (4MIDABLE-HR)
T. Bensby, M. Bergemann, J. Rybizki +21
The signatures of the formation and evolution of a galaxy are imprinted in its stars. Their velocities, ages, and chemical compositions present major constraints on models of galax…
4MOST Consortium Survey 3: Milky Way Disc and Bulge Low-Resolution Survey (4MIDABLE-LR)
C. Chiappini, I. Minchev, E. Starkenburg +35
The mechanisms of the formation and evolution of the Milky Way are encoded in the orbits, chemistry and ages of its stars. With the 4MOST MIlky way Disk And BuLgE Low-Resolution Su…
4MOST Consortium Survey 2: The Milky Way Halo High-Resolution Survey
N. Christlieb, C. Battistini, P. Bonifacio +19
We will study the formation history of the Milky Way, and the earliest phases of its chemical enrichment, with a sample of more than 1.5 million stars at high galactic latitude. El…
4MOST: Project overview and information for the First Call for Proposals
R. S. de Jong, O. Agertz, A. Agudo Berbel +335
We introduce the 4-metre Multi-Object Spectroscopic Telescope (4MOST), a new high-multiplex, wide-field spectroscopic survey facility under development for the four-metre-class Vis…
Non-local thermodynamic equilibrium stellar spectroscopy with 1D and 3D models - II. Chemical properties of the Galactic metal-poor disc and the halo
Maria Bergemann, Remo Collet, Ralph Schoenrich +5
From exploratory studies and theoretical expectations it is known that simplifying approximations in spectroscopic analysis (LTE, 1D) lead to systematic biases of stellar parameter…
Non-local thermodynamic equilibrium stellar spectroscopy with 1D and <3D> models - I. Methods and application to magnesium abundances in standard stars
Maria Bergemann, Remo Collet, Anish M. Amarsi +3
We determine Mg abundances in 6 Gaia benchmark stars using theoretical one-dimensional (1D) hydrostatic model atmospheres, as well as temporally- and spatially-averaged 3D model at…