TASS Mark IV Photometric Survey of the Northern Sky

Droege, T.; Richmond, M.; Sallman, M.; Creager, Robert P.

doi:10.1086/510197

Cited by 160 publications

(138 citation statements)

References 24 publications

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“…Our estimates are in good agreement with previous published values (O'Donavan et al 2006;Droege et al 2006).…”

Section: Discussionsupporting

confidence: 94%

“…We finally derive the Bessell V , R and I magnitudes of the TrES-2 parent star obtained from the average of all 32 individual measurements. The errors given correspond to the standard deviation of these measurements: Our value for the V , R and I magnitudes are in good agreement with ther ones published by O'Donavan et al (2006) and Droege et al (2006).…”

Section: Absolute Photometrysupporting

confidence: 92%

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Planetary transit observations at the University Observatory Jena: TrES‐2

Raetz¹,

Mugrauer²,

Schmidt³

et al. 2009

Astron Nachr

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We report on observations of several transit events of the transiting planet TrES-2 obtained with the Cassegrain-TeleskopKamera at the University Observatory Jena. Between March 2007 and November 2008 ten different transits and almost a complete orbital period were observed. Overall, in 40 nights of observation 4291 exposures (in total 71.52 h of observation) of the TrES-2 parent star were taken. With the transit timings for TrES-2 from the 34 events published by the TrESnetwork, the Transit Light Curve project and the Exoplanet Transit Database plus our own ten transits, we find that the orbital period is P = (2.470614 ± 0.000001) d, a slight change by ∼ 0.6 s compared to the previously published period. We present new ephemeris for this transiting planet. Furthermore, we found a second dip after the transit which could either be due to a blended variable star or occultation of a second star or even an additional object in the system. Our observations will be useful for future investigations of timing variations caused by additional perturbing planets and/or stellar spots and/or moons.

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“…Our estimates are in good agreement with previous published values (O'Donavan et al 2006;Droege et al 2006).…”

Section: Discussionsupporting

confidence: 94%

Section: Absolute Photometrysupporting

confidence: 92%

Planetary transit observations at the University Observatory Jena: TrES‐2

Raetz¹,

Mugrauer²,

Schmidt³

et al. 2009

Astron Nachr

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show abstract

“…We used the relationship for T eff and V; log θ = 3.0415(log T eff ) 2 − 25.4696 log T eff + 53.7010 − 0.2V der , where θ is the angular diameter in milliarcseconds. Using the Droege et al (2006) magnitudes, the fitted radii, and the observed T eff , we calculated the distance according to this relation d SB (also given in Table 13), and these were found to agree with those using the distance modulus.…”

Section: Determination Of Distancementioning

confidence: 80%

Fundamental properties of fiveKeplerstars using global asteroseismic quantities and ground-based observations

Creevey

Doğan

Frasca

et al. 2012

A&A

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We present an asteroseismic study of the solar-like stars KIC 11395018, KIC 10273246, KIC 10920273, KIC 10339342, and KIC 11234888 using short-cadence time series of more than eight months from the Kepler satellite. For four of these stars, we derive atmospheric parameters from spectra acquired with the Nordic Optical Telescope. The global seismic quantities (average large frequency separation and frequency of maximum power), combined with the atmospheric parameters, yield the mean density and surface gravity with precisions of 2% and ∼0.03 dex, respectively. We also determine the radius, mass, and age with precisions of 2-5%, 7-11%, and ∼35%, respectively, using grid-based analyses. Coupling the stellar parameters with photometric data yields an asteroseismic distance with a precision better than 10%. A v sin i measurement provides a rotational period-inclination correlation, and using the rotational periods from the recent literature, we constrain the stellar inclination for three of the stars. An Li abundance analysis yields an independent estimate of the age, but this is inconsistent with the asteroseismically determined age for one of the stars. We assess the performance of five grid-based analysis methods and find them all to provide consistent values of the surface gravity to ∼0.03 dex when both atmospheric and seismic constraints are at hand. The different grid-based analyses all yield fitted values of radius and mass to within 2.4σ, and taking the mean of these results reduces it to 1.5σ. The absence of a metallicity constraint when the average large frequency separation is measured with a precision of 1% biases the fitted radius and mass for the stars with non-solar metallicity (metal-rich KIC 11395018 and metal-poor KIC 10273246), while including a metallicity constraint reduces the uncertainties in both of these parameters by almost a factor of two. We found that including the average small frequency separation improves the determination of the age only for KIC 11395018 and KIC 11234888, and for the latter this improvement was due to the lack of strong atmospheric constraints.

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“…A good example is represented by the nearby young visual binary HIP 115147 (V368 Cep) and its reported comoving companion (Makarov et al 2007), which are also projected towards the same region of the sky. HIP 115147 is currently classified as a very young "naked" PTTS (Nations et al 1990;Chugainov et al 1991Chugainov et al , 1993, 20 to 50 Myr old, located at 20 pc whose origin remains disputed although it is A&A 520, A94 (2010) Zacharias et al (2004); (b) Monet et al (2003); (c) Droege et al (2006); (d) corrected from the contribution of the nearby companion. Table 3.…”

Section: Introductionmentioning

confidence: 99%

Discovery of “isolated” co-moving T Tauri stars in Cepheus

Guillout

Frasca

Klutsch

et al. 2010

A&A

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Context. During the course of a large spectroscopic survey of X-ray active late-type stars in the solar neighbourhood, we discovered four lithium-rich stars packed within just a few degrees on the sky. Although located in a sky area rich in CO molecular regions and dark clouds, the Cepheus-Cassiopeia complex, these very young stars are projected several degrees away from clouds in front of an area void of interstellar matter. As such, they are very good "isolated" T Tauri star candidates. Aims. We present optical observations of these stars conducted with 1-2 m class telescopes. We acquired high-resolution optical spectra as well as photometric data allowing us to investigate in detail their nature and physical parameters with the aim of testing the "runaway" and "in-situ" formation scenarios. Their kinematical properties are also analyzed to investigate their possible connection to already known stellar kinematic groups. Methods. We use the cross-correlation technique and other tools developed by us to derive accurate radial and rotational velocities and perform an automatic spectral classification. The spectral subtraction technique is used to infer chromospheric activity level in the Hα line core and clean the spectra of photospheric lines before measuring the equivalent width of the lithium absorption line. Results. Both physical (lithium content, chromospheric, and coronal activities) and kinematical indicators show that all stars are very young, with ages probably in the range 10-30 Myr. In particular, the spectral energy distribution of TYC 4496-780-1 displays a strong near-and far-infrared excess, typical of T Tauri stars still surrounded by an accretion disc. They also share the same Galactic motion, proving that they form a homogeneous moving group of stars with the same origin. Conclusions. The most plausible explanation of how these "isolated" T Tauri stars formed is the "in-situ" model, although accurate distances are needed to clarify their connection with the Cepheus-Cassiopeia complex. The discovery of this loose association of "isolated" T Tauri stars can help to shed light on atypical formation processes of stars and planets in low-mass clouds.

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TASS Mark IV Photometric Survey of the Northern Sky

Cited by 160 publications

References 24 publications

Planetary transit observations at the University Observatory Jena: TrES‐2

Planetary transit observations at the University Observatory Jena: TrES‐2

Fundamental properties of fiveKeplerstars using global asteroseismic quantities and ground-based observations

Discovery of “isolated” co-moving T Tauri stars in Cepheus

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