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In this work we present the results of our analysis of 16,300 medium-resolution LAMOST spectra of late-type stars in the Kepler field with the aim of determining the stellar parameters, activity level, lithium atmospheric content, and binarity. We have used a version of the code ROTFIT specifically developed for these spectra. We provide a catalog with the atmospheric parameters (Teff, log(g), and [Fe/H]), radial velocity (RV), and projected rotation velocity (vsini). For cool stars (Teff < 6500 K), we also calculated the H-alpha and LiI-6708 equivalent width, which are important indicators of chromospheric activity and evolutionary stage, respectively. We have derived the RV and atmospheric parameters for 14,300 spectra of 7443 stars. Literature data were used for a quality control of the results. The Teff and log(g) values are in good agreement with the literature. The [Fe/H] values appear to be overestimated for metal-poor stars. We propose a relation to correct the [Fe/H] values derived with ROTFIT. We were able to identify double-lined binaries, stars with variable RVs, lithium-rich giants, and emission-line objects. Based on the H-alpha flux, we found 327 active stars. We detected the LiI-6708 line and measure its equivalent width for 1657 stars, both giants and stars on the main sequence. Regarding the latter, we performed a discrete age classification based on the atmospheric lithium abundance and the upper envelopes of a few open clusters. Among the giants, we found 195 Li-rich stars, 161 of which are reported here for the first time. No relationship is found between stellar rotation and lithium abundance, which allows us to rule out merger scenarios as the predominant explanation of the enrichment of Li in our sample. The fraction of Li-rich giants, about 4%, is higher than expected., 32 pages, 34 figures; accepted for publication in Astronomy & Astrophysics

We present analysis of a new pulsating helium-atmosphere (DB) white dwarf, EPIC~228782059, discovered from 55.1~days of {\em K2} photometry. The long duration, high quality light curves reveal 11 independent dipole and quadruple modes, from which we derive a rotational period of $34.1 \pm 0.4$~hr for the star. An optimal model is obtained from a series of grids constructed using the White Dwarf Evolution Code, which returns $M_{*} = 0.685 \pm 0.003 M_{\odot}$, $T_{\rm{eff}}= 21{,}910 \pm 23$\,K and $\log g = 8.14 \pm0.01$\,dex. These values are comparable to those derived from spectroscopy by Koester \& Kepler ($20{,}860 \pm 160$\,K and $7.94 \pm0.03$\,dex). If these values are confirmed or better constrained by other independent works, it would make EPIC~228782059 one of the coolest pulsating DB white dwarf star known, and would be helpful to test different physical treatments of convection, and to further investigate the theoretical instability strip of DB white dwarf stars., 9 pages, 5 figures, 2 tables, accepted by ApJ

The radial velocity (RV) is a basic physical quantity which can be determined through Doppler shift of the spectrum of a star. The precision of RV measurement depends on the resolution of the spectrum we used and the accuracy of wavelength calibration. In this work, radial velocities of LAMOST-II medium resolution (R ~ 7500) spectra are measured for 1,594,956 spectra (each spectrum has two wavebands) through matching with templates. A set of RV standard stars are used to recalibrate the zero point of the measurement, and some reference sets with RVs derived from medium/high-resolution observations are used to evaluate the accuracy of the measurement. Comparing with reference sets, the accuracy of our measurement can get 0.0227 km s/1 with respect to radial velocities standard stars. The intrinsic precision is estimated with the multiple observations of single stars, which can achieve to 1.36 km s/1,1.08 km s/1, 0.91 km s/1 for the spectra at signal-to-noise levels of 10, 20, 50, respectively., published by ApJs. 13 pages, 13 figures

Following the LAMOST Spectroscopic Survey and Xuyi's Photometric Survey of the Galactic anti-center (GAC), we plan to conduct a time-domain survey of GAC to study the variable sky using Nanshan 1m telescope. The survey will be conducted during winter (in Nov., Dec., and Jan.). The first goal of the survey is to cover 270 sq.deg. of sky area in three years. The survey intends to detect some strong transient events of stars and find some short time-scale variable stars of different types. In this paper, we introduce the survey and present the preliminary results already carried out.

International audience; This paper analyses the Whole Earth Telescope observations of HL Tau 76, the first discovered pulsating DA white dwarf. The star was observed during two Whole Earth Telescope campaigns. It was a second priority target during the XCOV13 campaign in 1996 and the first priority one during the XCOV18 campaign in 1999. The 1999 campaign reached 66.5% duty cycle. With a total duration of 18 days, the frequency resolution achieved is 0.68 ?Hz. With such a frequency resolution, we were able to find as many as 78 significant frequencies in the power spectrum, of which 34 are independent frequencies after removal of all linear combinations. In taking into account other frequencies present during the 1996 WET campaign and those present in earlier data, which do not show up in the 1999 data set, we find a total of 43 independent frequencies. This makes HL Tau 76 the richest ZZ Ceti star in terms of number of observed pulsation modes. We use those pulsation frequencies to determine as much as possible of the internal structure of HL Tau 76. The pulsations in HL Tau 76 cover a wide range of periods between 380 s and 1390 s. We propose an identification for 39 of those 43 frequencies in terms of ?=1 and ?=2 non-radial g-modes split by rotation. We derive an average rotation period of 2.2 days. The period distribution of HL Tau 76 is best reproduced if the star has a moderately "thick" hydrogen mass fraction log qH ? -7.0. The results presented in this paper constitute a starting point for a detailed comparison of the observed periods with the periods calculated for models as representative as possible of HL Tau 76.

We present a second season of CCD time-series observations of Trumpler 24 in Johnson B and V obtained in 2004. 18 new variable stars are found, 15 variables discovered in Paper I are discussed, and the variability class of 5 of them is given. (© 2005 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)

We present 23 new times of maximum light of the SX Phoenicis star CY Aquarii. The O-C diagram reveals a new value of the period P= 0: 061038394 0: d 000000006 since 1996. CY Aqr is the first SX Phe star where the major component of the long-term period change can be represented without invoking large-amplitude period jumps. A linear period change combined with the light-time eect in a highly-eccentric orbit yields a reasonably precise solution. The binary explanation, however, does not account for the full magnitude of the period changes, and small residuals in the time interval 1930-1950 seem to remain.

We report on the 323 hours of nearly uninterrupted time series photometric observations of the DBV star GD 358 acquired with the Whole Earth Telescope (WET) during May 23 to June 8, 2000. We acquired more than 232 000 independent measurements and detected the non-radial g-modes consistent with degree ℓ = 1 and radial order 8 to 20 and their linear combinations up to 6th order. We also detect, for the first time, a high amplitude ℓ = 2 mode, with a period of 796 s. In the 2000 WET data, the largest amplitude modes are similar to those detected with the WET observations of 1990 and 1994, but the highest combination order previously detected was 4th order.

After the \O C" technique is used to study the pulsation of the Scuti star VZ Cnc with the times of maximum light listed in the literature and a newly- determined time based on new photometry for this star, some high-quality photometry light curves in the litera- ture are analysed by the Fourier decomposition, showing that there are more than 2 frequencies in the pulsation of this star, which might be one possible explanation of the existence of the large scatter in the \O C" diagram.

"The preliminary results of a multisite photometric campaign on the Pleiades Delta Scuti variable V650 Tauri are reported. The star was observed photometrically for 14 days during 2008 November from three observatories distributed in Longitude around the Earth. As a result of the preliminary analysis we have detected in V650 Tauri at least nine oscillation frequencies above a 99% confidence level."

The ZZ Ceti HS 0507+0434B is of special interest because it lies in a common proper motion system with HS 0507+0434A, another DA white dwarf of Teff = 20000 K. It lies in the middle of the instability strip and is a potentially useful pulsator to study the convection‐pulsation interaction. Its pulsation spectrum has shown 10 independent frequencies and a number of linear combinations. In an effort to better constrain its internal structure, we have performed new observations of HS 0507+0434B. We describe these new data obtained from mono‐site as well as multi‐site campaigns between 2007 and 2010. The analysis of these data reveals a complex behavior of the pulsator, with both frequency and amplitude variations on this 1.5 year time scale. We identify 7 l = 1 multiplets. We computed a grid of models and their l = 1 g‐modes. We then applied a χ2 fit method to derive a preliminary best fit model with: M*/M⊙ = 0.70, L/L⊙ = 3.5×10−3, Teff = 12080 K, MH/M* = 10−4.4.The ZZ Ceti HS 0507+0434B is of special interest because it lies in a common proper motion system with HS 0507+0434A, another DA white dwarf of Teff = 20000 K. It lies in the middle of the instability strip and is a potentially useful pulsator to study the convection‐pulsation interaction. Its pulsation spectrum has shown 10 independent frequencies and a number of linear combinations. In an effort to better constrain its internal structure, we have performed new observations of HS 0507+0434B. We describe these new data obtained from mono‐site as well as multi‐site campaigns between 2007 and 2010. The analysis of these data reveals a complex behavior of the pulsator, with both frequency and amplitude variations on this 1.5 year time scale. We identify 7 l = 1 multiplets. We computed a grid of models and their l = 1 g‐modes. We then applied a χ2 fit method to derive a preliminary best fit model with: M*/M⊙ = 0.70, L/L⊙ = 3.5×10−3, Teff = 12080 K, MH/M* = 10−4.4.

KUV 08368+4026 was considered a member of ZZ Ceti stars with large amplitudes and frequencies around a narrow range of 1.6 mHz and 2.0 mHz. As the first effort of asteroseismological study for KUV 08368+4026 since the discovery of its variability in 1996, a single‐site run in February of 2009 and a 3‐site observation campaign from December of 2009 to January of 2010 for KUV 08368+4026 were carried out in China and Mexico. More than 15,000 frames on 32 nights were obtained. 19 frequencies were distinguished in the datasets with 8 frequencies identified as independent modes. These results are helpful in determining stellar parameters including mass, rotation period, hydrogen mass fraction, and in constructing practical stellar and oscillation models, which will bring new knowledge about the internal structures of ZZ Ceti stars.

The preliminary results of a three-site CCD photometric campaign are reported. The $\delta$ Scuti variable V650 Tauri belonging to the Pleiades cluster was observed photometrically for 14 days on three continents during 2008 November. An overall run of 164 hr of data was collected. At least five significant frequencies for V650 Tauri have been detected., Comment: Proceedings of the International Conference "Stellar Pulsation: Challenges for Theory and Observation", AIP Conf. Proc., Vol. 1170, issue 1, pp. 426-428

As part of a observational project aiming to investigate the effects of rotation on main‐sequence g‐mode non‐radial pulsation we have obtained at least one (generally more) high‐resolution spectroscopic observation of more than 50 confirmed or candidate γ Doradus and slowly pulsating B stars and have completed a spectroscopic multi‐site campaign. The campaign was one of those outlined in De Cat et al. (these proceedings) and included five observatories and focused on the γ Doradus, and now planet hosting star HD 218396 (HR 8799) and the SPB stars HD 21071 and HD 25558.

We introduce the spectroscopic multi‐site campaigns that are organised for a sample of slowly pulsating B and γ Doradus stars to make a big step forward in the asteroseismic studies of these main‐sequence g‐mode pulsators.

The white dwarf cooling time depends on the mass and chemical composition of 1) the degenerate core, which is the thermal energy reservoir, and 2) the outer layers, which determine the rate at which this energy is radiated. As the DA dominate the white dwarf population, it is crucial to estimate their hydrogen content, M H . Asteroseismology provides tools to derive M H . To apply them, one needs to detect and identify a sufficient number of pulsation modes. This is not the case for the DAVs which exhibit only a few modes. Where M H has been deduced from asteroseismology, its determination relies on a small number of modes, and often suffers from ambiguous identification. We present a preliminary study of the DAV G 255-2, a potentially interesting ZZ Ceti in this context.

The pulsating DAV white dwarf G185-32 was observed with the Whole Earth Telescope in 1992, during XCov8. We briefly report on the weighted Fourier transform of the data obtained.

Trumpler 24 is a comparatively poorly-studied young open cluster. To investigate the correlation between the Be phe- nomenon and the cluster age, and to study the stellar variability in Trumpler 24, CCD time-series observations were made in 2001, and spectra were obtained in 2002. The results reveal 21 new variable stars, including 3 eclipsing binaries, no Be stars.

The pulsating PG 1159 planetary nebula central star RXJ 2117+3412 has been observed over three successive seasons of a multisite photometric campaign. The asteroseismological analysis of the data, based on the 37 identified l = 1 modes among the 48 independent pulsation frequencies detected in the power spectrum, leads to the derivation of the rotational splitting, the period spacing and the mode trapping cycle and amplitude, from which a number of fundamental parameters can be deduced. The average rotation period is 1.16 ± 0.05 days. The trend for the rotational splitting to decrease with increasing periods is incompatible with a solid body rotation. The total mass is 0.56⁺⁰˙⁰²₋₀.₀₄ Mѳ and the He-rich envelope mass fraction is in the range 0.013–0.078 M*. The luminosity derived from asteroseismology is log(L/Lѳ) = 4.05⁺⁰˙²³₋₀.₃₂ and the distance 760⁺²³⁰₋₂₃₅ pc. At such a distance, the linear size of the planetary nebulae is 2.9 ± 0.9 pc. The role of mass loss on the excitation mechanism and its consequence on the amplitude variations is discussed.

Photometric data obtained on the DA type white dwarf star G255-2 between 1991 and 1997 were reduced and the pulsation spectrum was explored with the standard process. The further analysis provides 10 normal, probably l = 1, independent nonradial eigenmodes.

We report the discovery of two new pulsating DA variables. The candidates have been selected from the KISO survey (Nogushi et al. 1980). The selection has been based on the color indices of the objects.