FIASCO: A new spectrograph at the University Observatory Jena

A new spectrograph (FIASCO) is in operation at the 0.9 m telescope of the University Observatory Jena. This article describes the characterization of the instrument and reports its first astronomical observations, among those lithium (6708 Å) detection in the atmosphere of young stars, and the simultaneous photometric and spectroscopic monitoring of variable stars (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

Photometric study of the OB star clusters NGC 1502 and NGC 2169 and mass estimation of their members at the University Observatory Jena

In this work we present detailed photometric results of the trapezium like galactic nearby OB clusters NGC 1502 and NGC 2169 carried out at the University Observatory Jena. We determined absolute BVRI magnitudes of the mostly resolved components using Landolt standard stars. This multi colour photometry enables us to estimate spectral type and absorption as well as the masses of the components, which were not available for most of the cluster members in the literature so far, using models of stellar evolution. Furthermore, we investigated the optical spectrum of the components ADS 2984A and SZ Cam of the sextuple system in NGC 1502. Our spectra clearly confirm the multiplicity of these components, which is the first investigation of this kind at the University Observatory Jena (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

Affordable échelle spectroscopy with a 60 cm telescope

A new fiber‐fed spectrograph was installed at the 60 cm telescope of the Stará Lesná Observatory. The article presents tests of its performance (spectral resolution, signal‐to‐noise ratio, radial‐velocity stability) and reports observations of selected variable stars and exoplanet host stars. First test observations show that the spectrograph is an ideal tool to observe bright eclipsing and spectroscopic binaries but also symbiotic and nova‐like stars. The radial‐velocity stability (60–80 m s^–1) is sufficient to study spectroscopic binaries and to detect easily the orbital motion of hot‐Jupiter extrasolar planets around bright stars. (© 2015 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

Elemental abundance analyses with DAO spectrograms: XXX. The middle B through early A stars ξ2 Ceti (B9 III), 21 Aquilae (B8 II‐III), ι Aquilae (B5 III), and ι Delphini (A2V)

This series of high quality elemental abundance analyses of mostly main‐sequence band normal and peculiar B, A, and F stars defines their properties and provides data for the comparison with the analyses of somewhat similar stars and with theoretical predictions. Most use high dispersion and high S/N (≥ 200) spectrograms obtained with CCD detectors at the long camera of the Coudé spectrograph of the 1.22‐m Dominion Astrophysical Observatory telescope. Here we reanalyze 21 Aql with better quality spectra and increase the number of stars consistently analyzed in the spectral range B5 to A2 by analyzing three new stars for this series. In the early A stars the normal and non‐mCP stars have abundances with overlapping ranges. But more stars are needed especially in the B5 to B9 range. ξ² Cet on average has a solar composition with a few abundances outside the solar range while both 21 Aql and ι Aql have abundances marginally less than solar. The abundances of ι Del are greater than solar with a few elements such as Ca being less than solar. It is an Am star (© 2010 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

Photometric monitoring of the young star Par 1724 in Orion

We report new photometric observations of the ∼200 000 year old naked weak‐line run‐away T Tauri star Par 1724, located north of the Trapezium cluster in Orion. We observed in the broad band filters B, V, R, and I using the 90 cm Dutch telescope on La Silla, the 80 cm Wendelstein telescope, and a 25 cm telescope of the University Observatory Jena in Großschwabhausen near Jena. The photometric data in V and R are consistent with a ∼5.7 day rotation period due to spots, as observed before between 1960ies and 2000. Also, for the first time, we present evidence for a long‐term 9 or 17.5 year cycle in photometric data (V band) of such a young star, a cycle similar to that to of the Sun and other active stars (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

TIGRE: A new robotic spectroscopy telescope at Guanajuato,Mexico

TIGRE is a new robotic spectroscopy telescope located in central Mexico at the La Luz Observatory of the University of Guanajuato. The 1.2 m telescope is fiber‐coupled to an ´echelle spectrograph with a spectral resolving power exceeding 20000 over most of the covered spectral range between 3800 Å and 8800 Å, with a small gap of 130 Å around 5800 Å. TIGRE operates robotically, i.e. it (normally) carries out all observations without any human intervention, including, in particular, the target selection in any given observing night. In this paper we describe the properties of the TIGRE instrumentation and its technical realization, as well as our first operational experience with the performance and efficiency of the overall system. Finally, we present some examples of recent TIGRE observations. (© 2014 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

Variability of young stars: Determination of rotational periods of weak‐line T Tauri stars in the Cepheus‐Cassiopeia star‐forming region

We report on observation and determination of rotational periods of ten weak‐line T Tauri stars in the Cepheus‐Cassiopeia star‐forming region. Observations were carried out with the Cassegrain‐Teleskop‐Kamera (CTK) at University Observatory Jena between 2007 June and 2008 May. The periods obtained range between 0.49 d and 5.7 d, typical for weak‐line and post T Tauri stars (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

Measuring the mass accretion rates of Herbig Ae/Be stars with X‐shooter

We present the results of our observations of eight magnetic Herbig Ae/Be stars obtained with the X‐shooter spectrograph mounted on UT2 at the VLT. X‐shooter provides a simultaneous, medium‐resolution and high‐sensitivity spectrum over the entire wavelength range from 300 to 2500 nm. We estimate the mass accretion rates (Ṁ_acc) of the targets from 13 different spectral diagnostics using empiric calibrations derived previously for T Tauri‐type stars and brown dwarfs. We have estimated the mass accretion rates of our targets, which range from 2 × 10^–9 to 2 × 10^–7 M_⊙ yr^–1. Furthermore, we have found accretion rate variability with amplitudes of 0.10–0.40 dex taking place on time scales from one day to tens of days. Additional future night‐to‐night observations need to be carried out to investigate the character of Ṁ_acc variability in details. Our study shows that the majority of the calibration relations can be applied to Herbig Ae/Be stars, but several of them need to be re‐calibrated on the basis of new spectral data for a larger number of Herbig Ae/Be stars (© 2012 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

STK: A new CCD camera at the University Observatory Jena

The Schmidt‐Teleskop‐Kamera (STK) is a new CCD‐imager, which is operated since begin of 2009 at the University Observatory Jena. This article describes the main characteristics of the new camera. The properties of the STK detector, the astrometry and image quality of the STK, as well as its detection limits at the 0.9 m telescope of the University Observatory Jena are presented (© 2010 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

Multi‐frequency solar observations at Metsähovi Radio Observatory and KAIRA

We describe solar observations carried out for the first time jointly with Kilpisjärvi Atmospheric Imaging Receiver Array (KAIRA) and Aalto University Metshovi Radio Observatory (MRO). KAIRA is new radio antenna array observing the decimeter and meter wavelength range. It is located near Kilpisjärvi, Finland, and operated by the SodankyläGeophysical Observatory, University of Oulu. We investigate the feasibility of KAIRA for solar observations, and the additional benefits of carrying out multi‐instrument solar observations with KAIRA and the MRO facilities, which are already used for regular solar observations. The data measured with three instruments at MRO, and with KAIRA during time period 2014 April–October were analyzed. One solar radio event, measured on 2014 April 18, was studied in detail. Seven solar flares were recorded with at least two of the three instruments at MRO, and with KAIRA during the chosen time period. KAIRA is a great versatile asset as a new Finnish instrument that can also be used for solar observations. Collaboration observations with MRO instruments and KAIRA enable detailed multi‐frequency solar flare analysis. Flare pulsations, flare statistics and radio spectra of single flares can be investigated due to the broad frequency range observations. The Northern locations of both MRO and KAIRA make as long as 15‐hour unique solar observations possible during summer time. (© 2015 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

Wide‐Field Plate Archive of the University Observatory Jena

We present the archive of the wide‐field plate observations obtained at the University Observatory Jena, which is stored at the Astrophysical Institute of the Friedrich Schiller University Jena. The archive contains plates taken in the period February 1963 to December 1982 with the 60/90/180‐cm Schmidt telescope of the university observatory. A computer‐readable version of the plate metadata catalogue (for 1257 plates), the logbooks, as well as the digitized Schmidt plates in low and high resolution are now accessible to the astronomical community.This paper describes the properties of the archive, as well as the processing procedure of all plates in detail. (© 2014 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

A new flare star member candidate in the Pleiades cluster

We present a new flare star, which was discovered during our survey on a selected field at the edge of the Pleiades cluster. The field was observed in the period 2007–2010 with three different CCD‐cameras at the University Observatory Jena with telescopes from 25 to 90 cm. The flare duration is almost one hour with an amplitude in the R‐band of about 1.08 mag. The location of the flare star in a color‐magnitude diagram is consistent with age and distance of the Pleiades. In the optical PSF of the flare star there are two 2MASS objects (unresolved in most images in the optical Jena PSF), so it is not yet known which one of them is responsible for this flare. The BVRIJHK colors yield spectral types of M1 and M2 with extinction being A_v = 0.231 ± 0.024 mag and A_v = 0.266 ± 0.020 for those two stars, consistent with the Pleiades cluster (© 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

Stellar science from a blue wavelength range

From stellar spectra, a variety of physical properties of stars can be derived. In particular, the chemical composition of stellar atmospheres can be inferred from absorption line analyses. These provide key information on large scales, such as the formation of our Galaxy, down to the small‐scale nucleosynthesis processes that take place in stars and supernovae. By extending the observed wavelength range toward bluer wavelengths, we optimize such studies to also include critical absorption lines in metal‐poor stars, and allow for studies of heavy elements (Z ≥ 38) whose formation processes remain poorly constrained. In this context, spectrographs optimized for observing blue wavelength ranges are essential, since many absorption lines at redder wavelengths are too weak to be detected in metal‐poor stars. This means that some elements cannot be studied in the visual‐redder regions, and important scientific tracers and science cases are lost. The present era of large public surveys will target millions of stars. It is therefore important that the next generation of spectrographs are designed such that they cover a wide wavelength range and can observe a large number of stars simultaneously. Only then, we can gain the full information from stellar spectra, from both metal‐poor to metal‐rich ones, that will allow us to understand the aforementioned formation scenarios in greater detail. Here we describe the requirements driving the design of the forthcoming survey instrument 4MOST, a multi‐object spectrograph commissioned for the ESO VISTA 4 m‐telescope. While 4MOST is also intended for studies of active galactic nuclei, baryonic acoustic oscillations, weak lensing, cosmological constants, supernovae and other transients, we focus here on high‐density, wide‐area survey of stars and the science that can be achieved with high‐resolution stellar spectroscopy. Scientific and technical requirements that governed the design are described along with a thorough line blending analysis. For the high‐resolution spectrograph, we find that a sampling of ≥2.5 (pixels per resolving element), spectral resolution of 18000 or higher, and a wavelength range covering 393–436 nm, is the most well‐balanced solution for the instrument. A spectrograph with these characteristics will enable accurate abundance analysis (±0.1 dex) in the blue and allow us to confront the outlined scientific questions. (© 2015 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

Surface abundances of light elements for a large sample of early B-type stars – I. Spectral observations of 123 stars; measurements of hydrogen and helium lines; infrared photometry

High-resolution spectral observations of 123 B0–B5 stars in the main sequence evolutionary phase were obtained at two observatories, namely the McDonald Observatory (McDO) and the Crimean Astrophysical Observatory (CrAO). Accurate equivalent widths W of two Balmer lines, H β and H γ , and ten He  i lines were obtained for all the stars, as well as of the He  ii   λ 4686 line for the hottest ones. A careful analysis of the measured equivalent widths was performed. It is shown that there is a very good agreement between the W values derived from the McDO and CrAO spectra for 14 common stars. A comparison with published data leads to the conclusion that the W values measured earlier by some authors for strong He  i lines are very likely to be underestimated. Infrared photometric observations in the J , H , and K bands were performed for 70 programme stars. All these data will be used in other papers: in particular for the T _eff and log  g determination and for the He, C, N and O abundance analyses.     

Planetary transit observations at the University Observatory Jena: XO‐1b and TrES‐1

We report on observations of transit events of the transiting planets XO‐1b and TrES‐1 with a 25 cm telescope of the University Observatory Jena. With the transit timings for XO‐1b from all 50 available XO, SuperWASP, Transit Light Curve (TLC)‐Project‐ and Exoplanet Transit Database (ETD)‐data, including our own I ‐band photometry obtained in March 2007, we find that the orbital period is P = (3.941501 ± 0.000001) d, a slight change by ∼3 s compared to the previously published period. We present new ephemeris for this transiting planet. Furthermore, we present new R ‐band photometry of two transits of TrES‐1. With the help of all available transit times from literature this allows us to refine the estimate of the orbital period: P = (3.0300722 ± 0.0000002) d. Our observations will be useful for future investigations of timing variations caused by additional perturbing planets and/or stellar spots and/or moons (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

High precision radial velocities of southern solar-type stars by cross-correlation

A system for obtaining high-precision radial velocities of solar-type stars by spectral cross-correlation has been established at the Mt John University Observatory. The use of a fibre-feed between the telescope and échelle spectrograph has enabled a stability such that we can achieve a precision of better than 50 m s^–1.A programme of radial-velocity observations of 29 southern solar-type stars—of which two are IAU radial velocity standard stars—is under way with the prime objective being a search for low-mass companions to the stars. Ten further IAU radial-velocity standard stars are also being monitored.     

Analysis of high-resolution spectra of mildly metal-poor stars I. Spectral data and equivalent widths

A number of high resolution and high signal-to-noise ratio spectra of mildly metal-poor stars were obtained with the coudé echelle spectrograph attached to the 2.16m telescope at Xinglong Observation Base of Beijing Astronomical Observatory. The spectra of seven mildly metal-poor stars were processed with the MIDAS software package, and the equivalent widths of their spectral lines were measured. The measured equivalent widths together with an error analysis are presented.     

The Subaru Telescope High Dispersion Spectrograph (HDS)

The High Dispersion Spectrograph (HDS) is the échelle spectrograph for an open‐use instrument of the Subaru Telescope. The current status of the instrument is reviewed. The new image slicers that significantly improve the efficiency of observations with very high resolving power have been installed in the past three years. Brief overview of recent science results is given on studies of early generations of stars and extra‐solar planets. An upgrade plan and future prospects of this instrument are discussed. (© 2014 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

Elemental abundance analyses with DAO spectrograms: XXXI. The early F supergiants ν Her (F2 II) and 41 Cyg (F5 Ib‐II)

This series of high quality elemental abundance analyses of mostly Main Sequence normal and peculiar B, A, and F stars defines their properties and provides data for the comparison with analyses of somewhat similar stars and with theoretical predictions. Most use high dispersion and high S/N (≥ 200) spectrograms obtained with CCD detectors at the long camera of the 1.22‐m Dominion Astrophysical Observatory telescope's coudé spectrograph. Here we expand the range of stars examined to include two relatively quiescent F supergiants. ν Her (F2 II) and 41 Cyg (F5 Ib‐II) are analyzed as consistently as possible with previous studies. These LTE fine analyses use the ATLAS9 and the WIDTH9 programs of R. L. Kurucz. High signal‐to‐noise spectrograms and high quality atomic data were employed. The derived values of these photometrically constant stars are somewhat different with the abundances of ν Her being somewhat metal‐poor and those of 41 Cyg being crudely solar‐like. Our analyses indicate that the basic results of Luck & Wepfer (1995) who also studied ν Her and 41 Cyg are not likely to be significantly changed by new studies of all their stars. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

CTK: A new CCD Camera at the University Observatory Jena

The Cassegrain‐Teleskop‐Kamera (CTK) is a new CCD imager which is operated at the University Observatory Jena since begin of 2006. This article describes the main characteristics of the new camera. The properties of the CCD detector, the CTK image quality, as well as its detection limits for all filters are presented (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)