arXiv subjects

Peter De Cat

Publications and source records attributed to Peter De Cat.

At least 19 recordsLinked to original sources

arXiv2026

Unravelling Mass Transfer in Algols from Surface Abundances. I. Z Vulpeculae

The photospheric abundance pattern of the components is a sensitive probe of mass and angular momentum transfer in Algols. With the aim to trace the evolutionary history and disclosed efficiency of mass transfer in Algols we collected new high-resolution spectra for about a dozen Algols with the {\sc hermes} spectrograph at the Mercator Telescope on La Palma, Canary Islands. In the present paper, which is the first in the series, we present the results of a comprehensive analysis of Z Vul, a hot Algol-type system. We derived the absolute stellar quantities and elemental abundances for the components. The carbon-to-nitrogen (C/N) ratio is the most sensitive tracer of thermonuclear processing and mass transfer. It is found to be within expected value for gainer but donor lacks the severe C/N inversion traditionally expected for a deeply stripped star. An extensive grid of over three million evolutionary models was calculated with the Cambridge \texttt{STARS} code which allows determination of the best-fitting and all surviving models. Constraints from the He and CNO abundances indicate that Z Vul underwent an episode of nearly conservative mass transfer during the Main Sequence life-time of the originally more massive component (Case A). Our detailed chemical tagging confirms that the surface abundances of the mass-losing component represent the delicately stripped outer layers still not reaching the CNO-rich core. This underscores the need of coupling high-resolution spectroscopic abundances with interior stellar profiles to accurately reconstruct the evolutionary history of interacting binaries.

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arXiv2026

High-precision K2/TESS Photometry and HERMES Spectroscopy of Four Bright Field Stars

Space-based photometry from K2 and TESS, coupled with high-resolution spectroscopy, provides a unique opportunity to re-examine the variability and chemical nature of four bright stars (HD 73135, BD +19$^\circ$ 2045, BD +19$^\circ$ 2046, and TYC 1395-855-1), which were poorly characterised by the original ground-based campaign under the Nainital-Cape survey. We aim to establish the nature of the variability, chemical properties, and evolutionary status of these stars. We analysed ground-based Johnson $BV$ photometry combined with K2 and TESS time-series data to establish the nature of their variability. Using high-resolution HERMES spectroscopy, we determined their spectral classifications and chemical abundances. In addition, we used the inferred spectroscopic constraints with grid-based evolutionary modelling to derive their corresponding masses, radii, and ages. The frequency analysis reveals a diversity of low-amplitude variability across the sample. HD 73135 shows a persistent modulation near 1.5 d that is most consistent with rotation, although an ellipsoidal-binary interpretation cannot yet be excluded, while BD +19$^\circ$ 2045 exhibits multiple low-frequency signals and is identified as a new candidate $\gamma$ Doradus $g$-mode pulsator. BD +19$^\circ$ 2046 and TYC 1395-855-1 are non-variable or only marginally variable in K2 but display coherent low-frequency modulation in TESS of uncertain origin. Spectroscopically, HD 73135 is the only chemically peculiar star in the sample and shows a clear Am abundance pattern, whereas the other three stars are chemically normal. These results demonstrate the value of combining legacy survey data with contemporary photometric and spectroscopic analysis.

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arXiv2025

Asteroseismology of HD 23734, HD 68703, and HD 73345 using K2-TESS Space-based Photometry and High-resolution Spectroscopy

In this paper, we present a comprehensive study of three stars, HD 23734, HD 68703, and HD 73345, which were previously observed as chemically peculiar candidates within the Nainital-Cape survey and reported as null results for the pulsational variability. Frequency analyses of \ktwo\ and \tess\ time-series photometric data reveal the co-existence of rotational modulation and pulsation. We use the spectrum synthesis technique to determine fundamental parameters and chemical composition, which shows that all the three stars are likely to be chemically normal. The evolutionary status of the target stars corresponds to the main-sequence phases and places them within the $\delta$ Scuti instability strip of the Hertzsprung-Russell diagram. The line profile variability is observed in all three stars, especially intriguing in HD\,68703 and a typical signature of the non-radial pulsation, demands further detailed examination. Using \tess\ photometry, we identified the radial modes of orders $n$=3 and 4 for HD\,23734, $n$=1, 3, and 4 for HD\,68703, and $n$=3,4 and 5 for HD\,73345. In addition to the presence of pulsation and rotation, HD\,73345 exhibits a steady increase in radial velocity that we interpret as the star being likely to be part of a long-period binary system. Finally, we propose an extended campaign aimed for the in-depth spectroscopic and spectropolarimetric study of selected pulsating stars monitored under the Nainital-Cape survey project.

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arXiv2025

Chemical abundances and doppler imaging of the Ap Si/He-wk star HD 100357

We present the results of time-resolved photometry, abundance analysis and Doppler imaging of an Ap star, HD 100357. The {\it TESS} photometry revealed rotational modulation with a period of 1.6279247 days. Upon inspecting the residuals after removing the rotational period and its harmonics, we found additional frequencies around 15.8054 d$^{-1}$ which we later confirmed with ground-based observations as originating from a nearby star. Using high-resolution spectroscopy, we identified HD 100357 as an Ap Si/He-wk star exhibiting rotational modulation caused by surface abundance spots. The stellar parameters of HD 100357 were determined as $T_{\rm eff}$ = 11,850 K, $\log g$ = 4.57, $\upsilon\sin i$ = 60 km\,s$^{-1}$, and an inclination angle $i$ = 72$^{\circ}$. The detailed abundance analysis revealed strongly overabundant stratified silicon, an overabundance of iron-peak elements and rare earth elements combined with remarkably deficient helium. Mapping of Fe and Cr abundances revealed the existence of ring-shaped regions with a lower concentration of the elements. Their geometry might reflect the orientation of the hypothetical magnetic field of the star, oriented $\sim$90$^{\circ}$ to the rotational axis. HD 100357, with its strong chemical peculiarities and indications of possible magnetic fields, represents an interesting candidate for follow-up spectropolarimetric observations aimed at investigating its magnetic field topology and stellar activity.

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arXiv2025

Phase II of the LAMOST-Kepler/K2 Survey. II. Time Domain of Medium-resolution Spectroscopic Observations from 2018 to 2023

The LAMOST-Kepler/K2 Medium-Resolution Spectroscopic Survey (LK-MRS) conducted time-domain medium-resolution spectroscopic observations of 20 LAMOST plates in the Kepler and K2 fields from 2018 to 2023, a phase designated as LK-MRS-I. A catalog of stellar parameters for a total of 36,588 stars, derived from the spectra collected during these five years, including the effective temperature, the surface gravity, the metallicity, the {\alpha}-element abundance, the radial velocity, and v sin i of the target stars, is released, together with the weighted averages and uncertainties. At S/N = 10, the measurement uncertainties are 120 K, 0.18 dex, 0.13 dex, 0.08 dex, 1.9 km/s, and 4.0 km/s for the above parameters, respectively. Comparisons with the parameters provided by the APOGEE and GALAH surveys validate the effective temperature and surface gravity measurements, showing minor discrepancies in metallicity and {\alpha}-element abundance values. We identified some peculiar star candidates, including 764 metal-poor stars, 174 very metal-poor stars, and 30 high-velocity stars. Moreover, we found 2,333 stars whose radial velocity seems to be variable. Using Kepler/K2 or TESS photometric data, we confirmed 371 periodic variable stars among the radial velocity variable candidates and classified their variability types. LK-MRS-I provides spectroscopic data being useful for studies of the Kepler and K2 fields. The LK-MRS project will continue collecting time-domain medium-resolution spectra for target stars during the third phase of LAMOST surveys, providing data to support further scientific research.

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arXiv2025

The impact of stellar rotations and binaries on the shape of upper main sequence near turn off in open cluster NGC\,6067

We present the analysis of the extended Main Sequence Turn-Off (eMSTO) in the open cluster NGC\,6067. We derive the projected rotational velocity, \textit{v}sin\textit{i}, of the stars belonging to the eMSTO region of the main sequence (MS) utilizing \textit{Gaia}-ESO spectra. Our results reveal a positive correlation between \textit{v}sin\textit{i} and the color of eMSTO stars, where fast-rotating stars predominantly occupy the red part of the MS while slow-rotating ones prefer a bluer side of the MS. The gravity-darkening effect might be a reason for this correlation. We find that most of the close binaries present in the eMSTO population would be slow-rotating due to the tidal-locking phenomenon. We identify four double-lined spectroscopic binaries (SB2) featuring slow-rotating companions, further supporting this tidal-locking hypothesis. However, the spatial distribution and the cumulative radial distribution indicate a higher concentration of red eMSTO stars in the cluster's central region than their bluer counterparts. This suggests that tidal locking is less likely to be the cause of the observed spread in rotation rates among eMSTO stars. Instead, we propose that star-disk interactions during the pre-main-sequence phase might have played a crucial role in spreading the rotation rates of stars, leading to the eMSTO phenomenon in NGC\,6067.

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arXiv2025

Investigating Pulsating Variables and Eclipsing Binaries in NGC 2126 using Ground and Space-based Photometry, Astrometry, Spectroscopy and Modeling

Pulsating variables are prevalent in the classical δ Scuti instability strip of intermediate-age open star clusters. The cluster membership of these stars facilitates a comparative analysis of their evolution in analogous environments. In this study, we integrate ground-based observations, TESS Full Frame Images (FFIs), and Gaia DR3 data to investigate variable stars in the intermediate-age open star cluster NGC 2126. We performed ground-based time-series observations of NGC 2126 to identify variable stars within its vicinity. Next, we determined the membership of these stars using parallax and the proper motions from Gaia DR3 archive. Then, we searched the TESS Full Frame Images (FFIs) for counterparts to the variables identified above and performed their frequency analysis and classification. Finally, we modeled the light curves (LCs) of detected eclipsing binaries (EBs), including V551 Aur, which has a pulsating component. We found 25 members and 85 field variable stars. In TESS FFIs, we found LCs for 11 known variables and a new rotational variable. We determined that the pulsating EB V551 Aur is a member of the cluster. The low- and medium-resolution spectra revealed the line profile variation and the basic parameters for the star, respectively. Simultaneous modeling of the eclipses and the embedded pulsations resulted in improved orbital parameters for the binary system. We also report the determination of orbital parameters for the previously uncharacterized EB system UCAC4 700-043174.

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arXiv2024

Asteroseismology of the mild Am $δ$ Sct star HD 118660 : TESS photometry and modelling

We present the results of an asteroseismic study of HD 118660 (TIC 171729860), being a chemically peculiar (mild Am) star exhibiting $δ$ Scuti ($δ$ Sct) pulsations. It is based on the analysis of two sectors of time-series photometry from the space mission TESS and seismic modelling. It yielded the detection of 15 and 16 frequencies for TESS sectors 23 and 50, respectively. The identified pulsation modes include four radial ($\ell=0$) and five dipolar ($\ell=1$) ones. The radial modes are overtones with order $n$ ranging from $3$ and $6$. Such high values of $n$ are theoretically not expected for stars with the effective temperature of HD 118660 ($\rm T_{\rm eff}\approx 7550 \rm K$ ) located near the red edge of the $δ$ Sct instability strip. To estimate the asteroseismic parameters, we have generated a grid of stellar models assuming a solar metallicity ($Z=0.014$) and different values for the convective overshooting parameter ($0.1\leq α_{\rm ov}\leq 0.3$). We conclude that the analysis of the radial modes is insufficient to constrain $α_{\rm ov}$ and $Z$ for $δ$ Sct stars. The value for the equatorial velocity of HD 118660 derived from the seismic radius and the rotational frequency is consistent with values found in the literature.

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arXiv2023

Unresolved Rossby and gravity modes in 214 A and F stars showing rotational modulation

Here we report an ensemble study of 214 A- and F-type stars observed by \textit{Kepler}, exhibiting the so-called \textit{hump and spike} periodic signal, explained by Rossby modes (r~modes) -- the \textit{hump} -- and magnetic stellar spots or overstable convective (OsC) modes -- the \textit{spike} -- respectively. We determine the power confined in the non-resolved hump features and find additional gravity~modes (g~modes) humps always occurring at higher frequencies than the spike. Furthermore, we derive projected rotational velocities from FIES, SONG and HERMES spectra for 28 stars and the stellar inclination angle for 89 stars. We find a strong correlation between the spike amplitude and the power in the r and g~modes, which suggests that both types of oscillations are mechanically excited by either stellar spots or OsC modes. Our analysis suggests that stars with a higher power in $m=1$ r~modes humps are more likely to also exhibit humps at higher azimuthal orders ($m$ = 2, 3, or 4). Interestingly, all stars that show g~modes humps are hotter and more luminous than the observed red edge of the $δ$ Scuti instability strip, suggesting that either magnetic fields or convection in the outer layers could play an important role.

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arXiv2023

High-precision photometric and high-resolution spectroscopic characterisation of HD 180347

We report the analysis of high-precision space-based photometric and high-resolution spectroscopic observations of HD 180347. The high-quality light curves from the Transiting Exoplanet Survey Satellite (TESS) under sectors 14, 15, and 26 were used. By visual inspection of the light curves and the Fourier transforms, only low-frequency signals (less than 1 d$^{-1}$) were detected. After using wavelet, autocorrelation, and composite spectrum analyses, HD 180347 is classified as a rotational variable with a period of about 4.1 $\pm$ 0.2 days. In reference to the observation limit of TESS, no pulsations were detected. For the spectroscopic analysis, we used data collected with the High Efficiency and Resolution Mercator Échelle Spectrograph (HERMES). We determined the spectral type of this star and obtained atmospheric parameters such as the effective temperature, the surface gravity, and the projected rotational, microturbulent, and radial velocities. We performed a detailed chemical abundance analysis. The LTE abundances were derived for 25 chemical elements. For 13 of them, including Ca, Sc, Sr, Zr, and Ba, which are important for the characterisation of chemical peculiarity, we also present the non-local thermodynamic equilibrium (NLTE) abundances. NLTE improves the accuracy of the derived abundances and confirms that Ca and Sc are depleted in HD 180347 relative to their solar abundances, while the heavy elements beyond Sr are enhanced, by more than 0.7 dex. Based on the spectral class and the element abundance pattern, we classify this star as Am (kA1hA8mA8).

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arXiv2023

Optical characterization and Radial velocity monitoring with Belgian and Indian Telescopes (ORBIT): the eclipsing binaries EPIC 211982753 and EPIC 211915147

The K2 eclipsing binary candidates EPIC 211982753 (hereinafter called EPIC2753) and EPIC 211915147 (hereinafter called EPIC5147) are characterized with the help of photometric and high-resolution spectroscopic data. The light curve analysis uses the R-band photometric data from the 1.3-m Devasthal Fast Optical Telescope (DFOT, India), ASAS-3 and K2 observations. High-resolution echelle spectra are collected using the HERMES spectrograph at the 1.2-m MERCATOR telescope (La Palma, Spain). The synthetic light and radial velocity curves are generated with the help of the modeling package PHOEBE 1.0. The orbital period analysis based on the ~3.2 years of K2 observations does not show any change in the orbital period of both targets. The component masses M1,2 are estimated as 1.69(0.02) and 1.59(0.02) solar mass for EPIC2753, and 1.48(0.01) and 1.27(0.01) solar mass for EPIC5147. Both systems are high mass-ratio eclipsing binaries with q>0.85. The component radii R1,2 are found to be 1.66(0.02) and 1.53(0.02) solar radius for EPIC2753, and 1.80(0.05) and 1.42(0.05) solar radius for EPIC5147. The distances of EPIC2753 and EPIC5147 are determined as 238(4) and 199(5) pc, respectively. MESA Isochrones and Stellar Tracks are used to understand the evolutionary status of both systems.

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arXiv2022

Polarimetric detection of nonradial oscillation modes in the beta Cephei star beta Crucis

Here we report the detection of polarization variations due to nonradial modes in the beta Cephei star beta Crucis. In so doing we confirm 40-year-old predictions of pulsation-induced polarization variability and its utility in asteroseismology for mode identification. In an approach suited to other beta Cep stars, we combine polarimetry with space-based photometry and archival spectroscopy to identify the dominant nonradial mode in polarimetry, f2, as l = 3, m = -3 (in the m-convention of Dziembowski) and determine the stellar axis position angle as 25 (or 205) +/- 8 deg. The rotation axis inclination to the line of sight was derived as approx. 46 deg. from combined polarimetry and spectroscopy, facilitating identification of additional modes and allowing for asteroseismic modelling. This reveals a star of 14.5 +/- 0.5 Solar masses and a convective core containing approx. 28% of its mass -- making beta Crucis the most massive star with an asteroseismic age.

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arXiv2021

Long-term photometric and low-resolution spectroscopic analysis of five contact binaries

A photometric and spectroscopic investigation is performed on five W Ursae Majoris eclipsing binaries (EWs) J015818.6+260247 (hereinafter as J0158b), J073248.4+405538 (hereinafter as J0732), J101330.8+494846 (hereinafter as J1013), J132439.8+130747 (hereinafter as J1324) and J152450.7+245943 (hereinafter as J1524). The photometric data are collected with the help of the 1.3\,m Devasthal Fast Optical Telescope (DFOT), the 1.04\,m Sampurnanand Telescope (ST) and the TESS space mission. The low-resolution spectra of the 4\,m Large Sky Area Multi-Object Fiber Spectroscopic Telescope (LAMOST) are used for spectroscopic analysis. The orbital period change of these systems is determined using our and previously available photometric data from different surveys. The orbital period of J1013 and J1524 is changing with a rate of $-2.552(\pm0.249)\times 10^{-7}$ days $yr^{-1}$ and $-6.792(\pm0.952)\times 10^{-8}$ days $yr^{-1}$, respectively, while others do not show any orbital period change. The orbital period change of J1013 and J1524 corresponds to a mass transfer rate of $2.199\times10^{-7} M_{\odot}\,yr^{-1}$ and $6.151\times10^{-8}M_{\odot}\,yr^{-1}$ from the primary to the secondary component in these systems. It is likely that angular momentum loss via magnetic braking may also be responsible for the observed orbital period change in the case of J1524. All systems have a mass-ratio lower than 0.5, except J0158b with a mass-ratio of 0.71. All the systems are shallow type contact binaries. The J0158b and J1524 are A-subtype while others are W-subtype. The $H_α$ emission line region is compared with template spectra prepared using two inactive stars with the help of STARMOD program. The J0158, J1324 and J1524 systems show excess emission in the residual spectra after subtraction of the template.

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arXiv2021

HERMES spectroscopy of normal A and Am stars

The nominal Kepler mission provided very high-precision photometric data. Using these data, interesting phenomena such as spots, and ``hump and spike'' features were observed in the light curves of some normal A and metallic lined A stars (Am stars). However, the connection between such phenomena and the chemical peculiarity of the Am stars is still unclear. In order to make progress on these issues, its important to collect high-resolution spectroscopic data to determine their fundamental parameters and individual chemical abundances. In this paper, we present a spectroscopic study of a sample of ``hump and spike'' stars in the nominal Kepler field. We used data collected with the High Efficiency and Resolution Mercator Échelle Spectrograph (HERMES). We determined the spectral type of these stars and obtained the atmospheric stellar parameters such as effective temperatures, surface gravities, projected rotational, microturbulent and radial velocities. We also performed a detailed individual chemical abundance analysis for each target. We confirmed KIC 3459226 and KIC 6266219 as Am stars, KIC 9349245 as a marginal Am star, while KIC 4567097, KIC 4818496, KIC 5524045, KIC 5650229, KIC 7667560, and KIC 9272082 are non-Am stars. To estimate their evolutionary phases, all the stars were placed in the Hertzsprung-Russell (HR) diagram. Based on their spectral classification and chemical abundance pattern, we reclassified KIC 6266219 (previously treated as chemically normal) as an Am star (kA3hA7mF1) and KIC 9272082 (previously treated as Am) as non-Am.

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arXiv2021

Rotation and spots in normal A and Am/Fm stars

Frequency analysis of long-term ultra-precise photometry can lead to precise values of rotation frequencies of rotating stars with ``hump and spike'' features in their periodograms. Using these features, we computed the rotation frequencies and amplitudes. The corresponding equatorial rotational velocity ($v_{\rm rot}$) and spot size were estimated. On fitting the autocorrelation functions of the light-curves with the appropriate model, we determined the starspot decay-time scale. The $v_{\rm rot}$ agrees well with the projected rotational velocity ($v\,{\rm sin}\,i$) in the literature. Considering a single circular and black spot we estimate its radius from the amplitude of the ``spike''. No evidence for a significant difference in the average ``spike'' amplitude and spot radius was found for Am/Fm and normal A stars. Indeed, we derived an average value of $\rm \sim 21\pm2$ and $\sim 19\pm2\,{\rm ppm}$ for the photometric amplitude and of $\rm 1.01\,\pm\,0.13$ and $1.16\,\pm\,0.12\,R_{\rm E}$ for the spot radius (where $R_{\rm E}$ is the Earth radius), respectively. We do find a significant difference for the average spot decay-time scale, which amounts to $3.6\pm0.2$ and $1.5\pm0.2$ days for Am/Fm and normal A stars, respectively. In general, spots on normal A stars are similar in size to those on Am/Fm stars, and both are weaker than previously estimated. The existence of the ``spikes'' in the frequency spectra may not be strongly dependent on the appearance of starspots on the stellar surface. In comparison with G, K and M stars, spots in normal A and Am/Fm stars are weak which may indicate the presence of a weak magnetic field.

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arXiv2021

A homogeneous spectroscopic analysis of a Kepler legacy sample of dwarfs for gravity-mode asteroseismology

Asteroseismic modelling of the internal structure of main-sequence stars born with a convective core has so far been based on homogeneous analyses of space photometric Kepler light curves of 4 years duration, to which most often incomplete inhomogeneously deduced spectroscopic information was added to break degeneracies. We composed a sample of 111 dwarf gravity-mode pulsators observed by the Kepler space telescope whose light curves allowed for determination of their near-core rotation rates. For this sample we assembled HERMES high-resolution optical spectroscopy at the 1.2-m Mercator telescope. Our spectroscopic information offers additional observational input to also model the envelope layers of these non-radially pulsating dwarfs. We determined stellar parameters and surface abundances in a homogeneous way from atmospheric analysis with spectrum normalisation based on a new machine learning tool. Our results suggest a systematic overestimation of [M/H] in the literature for the studied F-type dwarfs, presumably due to normalisation limitations caused by the dense line spectrum of these rotating stars. CNO-surface abundances were found to be uncorrelated with the rotation properties of the F-type stars. For the B-type stars, we find a hint of deep mixing from C and O abundance ratios; N abundances have too large uncertainties to reveal a correlation with the rotation of the stars. Our spectroscopic stellar parameters and abundance determinations allow for future joint spectroscopic, astrometric (Gaia), and asteroseismic modelling of this legacy sample of gravity-mode pulsators, with the aim to improve our understanding of transport processes in the core-hydrogen burning phase of stellar evolution.

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arXiv2020

LAMOST Observations in 15 \textit{K}2 Campaigns: I. Low resolution spectra from LAMOST DR6

The LAMOST-\textit{K}2 (L\textit{K}2) project, initiated in 2015, aims to collect low-resolution spectra of targets in the \textit{K}2 campaigns, similar to LAMOST-\textit{Kepler} project. By the end of 2018, a total of 126 L\textit{K}2 plates had been observed by LAMOST. After cross-matching the catalog of the LAMOST data release 6 (DR6) with that of the \textit{K}2 approved targets, we found 160,619 usable spectra of 84,012 objects, most of which had been observed more than once. The effective temperature, surface gravity, metallicity, and radial velocity from 129,974 spectra for 70,895 objects are derived through the LAMOST Stellar Parameter Pipeline (LASP). The internal uncertainties were estimated to be 81 K, 0.15 dex, 0.09 dex and 5 kms$^{-1}$, respectively, when derived from a spectrum with a signal-to-noise ratio in the $g$ band (SNR$_g$) of 10. These estimates are based on results for targets with multiple visits. The external accuracies were assessed by comparing the parameters of targets in common with the APOGEE and GAIA surveys, for which we generally found linear relationships. A final calibration is provided, combining external and internal uncertainties for giants and dwarfs, separately. We foresee that these spectroscopic data will be used widely in different research fields, especially in combination with \textit{K}2 photometry.

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arXiv2020

Phase II of the LAMOST-Kepler/K2 survey. I. Time series of medium-resolution spectroscopic observations

Phase \RNum{2} of the LAMOST-{\sl Kepler/K}2 survey (LK-MRS), initiated in 2018, aims at collecting medium-resolution spectra ($R\sim7,500$; hereafter MRS) for more than $50,000$ stars with multiple visits ($\sim60$ epochs) over a period of 5 years (2018 September to 2023 June). We selected 20 footprints distributed across the {\sl Kepler} field and six {\sl K}2 campaigns, with each plate containing a number of stars ranging from $\sim2,000$ to $\sim 3,000$. During the first year of observations, the LK-MRS has already collected $\sim280,000$ and $\sim369,000$ high-quality spectra in the blue and red wavelength range, respectively. The atmospheric parameters and radial velocities for $\sim259,000$ spectra of $21,053$ targets were successfully calculated by the LASP pipeline. The internal uncertainties for the effective temperature, surface gravity, metallicity, and radial velocity are found to be $100$\,K, $0.15$\,dex, $0.09$\,dex, and $1.00$\,km\,s$^{-1}$, respectively. We found $14,997$, $20,091$, and $1,514$ stars in common with the targets from the LAMOST low-resolution survey (LRS), GAIA and APOGEE, respectively, corresponding to a fraction of $\sim70\%$, $\sim95\%$ and $\sim7.2\%$. In general, the parameters derived from LK-MRS spectra are consistent with those obtained from the LRS and APOGEE spectra, but the scatter increases as the surface gravity decreases when comparing with the measurements from APOGEE. A large discrepancy is found with the GAIA values of the effective temperature. The comparisons of radial velocities of LK-MRS to GAIA and LK-MRS to APOGEE nearly follow an Gaussian distribution with a mean $μ\sim1.10$ and $0.73$\,km\,s$^{-1}$, respectively.

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