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Observations of the transiting planet TrES-2 with the AIU Jena telescope in Großschwabhausen
St. Raetz, M. Mugrauer, T. O. B. Schmidt +9
We have started high precision photometric monitoring observations at the AIU Jena observatory in Grossschwabhausen near Jena in fall 2006. We used a 25 cm Cassegrain telescope equ…
Synergy of multifrequency studies from observations of NGC6334I
Andreas Seifahrt, Sven Thorwirth, Henrik Beuther +5
We combine multifrequency observations from the millimeter to near infrared wavelengths that demonstrate the spatial distributions of H2, CO, and NH3 emission, which are all manife…
A search for wide brown dwarf companions to stars within 10pc
Marin Treselj, Andreas Seifahrt, Klaus-Werner Hodapp +2
We present the first results of a large imaging survey to identify wide brown dwarf companions to stars within 10 pc. We have performed a deep (H-band limit ~ 19.0 mag), wide field…
Activity and rotation of low mass stars in young open clusters
Andreas Seifahrt, Ansgar Reiners, Aleks Scholz +1
We present first results from a multi-object spectroscopy campaign in IC2602, the Hyades, the Pleiades, and the Coma cluster using VLT/FLAMES. We analysed the data for radial veloc…
Observation and modelling of dusty, low gravity L, and M dwarfs
Andreas Seifahrt, Christiane Helling, Adam J. Burgasser +6
Observational facilities allow now the detection of optical and IR spectra of young M- and L-dwarfs. This enables empirical comparisons with old M- and L- dwarfs, and detailed stud…
Direct evidence of a sub-stellar companion around CT Cha
T. O. B. Schmidt, R. Neuhäuser, A. Seifahrt +5
In our ongoing search for close and faint companions around T Tauri stars, we found a very faint (Ks=14.9mag, Ks_0=14.4mag) object, just ~2.67" northwest of the Chamaeleon star-for…
High Precision Radial Velocity Measurements in the Infrared: A First Assessment of the RV Stability of CRIRES
Andreas Seifahrt, Hans-Ulrich Kaeufl
High precision radial velocity (RV) measurements in the near infrared are on high demand, especially in the context of exoplanet search campaigns shifting their interest to late ty…
Observational Consequences of the Recently Proposed Super-Earth Orbiting GJ436
Jacob L. Bean, Andreas Seifahrt
Ribas and collaborators have recently proposed that an additional, ~5 M_earth planet orbits the transiting planet host star GJ436. Long-term dynamical interactions between the two…
A Hubble Space Telescope transit light curve for GJ436b
J. L. Bean, G. F. Benedict, D. Charbonneau +6
We present time series photometry for six partial transits of GJ436b obtained with the Fine Guidance Sensor instrument on the Hubble Space Telescope (HST). Our analysis of these da…
Search for extrasolar planets with high-precision relative astrometry
T. Roell, A. Seifahrt, R. Neuhäuser
We present our search program for substellar companions using high-precision relative astronomy. Due to its orbital motion around the star, an unseen substellar companion would pro…
Confirmation of the binary status of Cha Halpha 2 - a very young low-mass binary in Chamaeleon
T. O. B. Schmidt, R. Neuhäuser, N. Vogt +3
Neuhaeuser & Comeron (1998, 1999) presented direct imaging evidence, as well as first spectra, of several young stellar and sub-stellar M6- to M8-type objects in the Cha I dark clo…
Improved orbital solution and masses for the very low-mass multiple system LHS 1070
A. Seifahrt, T. Roell, R. Neuhaeuser +5
We present a refined orbital solution for the components A, B, and C of the nearby late-M type multiple system LHS 1070. By combining astrometric datapoints from NACO/VLT, CIAO/SUB…
Astrometric and photometric monitoring of GQ Lup and its sub-stellar companion
Ralph Neuhaeuser, Markus Mugrauer, Andreas Seifahrt +2
Neuhaeuser et al. (2005) presented direct imaging evidence for a sub-stellar companion to the young T Tauri star GQ Lup. Common proper motion was highly significant, but no orbital…
Detection of strong activity in the eclipsing binary brown dwarf 2MASSJ05352184-0546085 - A possible explanation for the temperature reversal
A. Reiners, A. Seifahrt, K. G. Stassun +2
We show high resolution spectra of the eclipsing brown dwarf binary 2MASSJ05352184-0546085 taken at the two opposite radial velocity maxima. Comparisons of the TiO bands to model a…
Spectral type dependent rotational braking and strong magnetic flux in three components of the late-M multiple system LHS 1070
Ansgar Reiners, Andreas Seifahrt, Hans Ulrich Käufl +2
We show individual high resolution spectra of components A, B, and C of the nearby late-M type multiple system LHS 1070. Component A is a mid-M star, B and C are known to have mass…
Probing micro-arcsec astrometry with NACO
Andreas Seifahrt, Tristan Roell, Ralph Neuhaeuser
Relative astrometric measurements with a precision far better than 1 mas (milli-arcsec) are commonly regarded as the domain of interferometry. Pioneering work by Pravdo & Shaklan (…
VSOP: The Variable Star One-shot Project I. Project presentation and first data release
T. H. Dall, C. Foellmi, J. Pritchard +21
The Variable Star One-shot Project (VSOP) is aimed at (1) providing the variability type and spectral type of all unstudied variable stars, (2) process, publish, and make the data…
The Variable Star One-shot Project, and its little child: Wikimbad
C. Foellmi, T. H. Dall, J. Pritchard +21
The Variable Star One-shot Project (VSOP) aimed at providing to the world-wide stellar community the necessary one-shot spectrum of unstudied variable stars, too often classified a…
Low mass visual binaries in the solar neighbourhood: The case of HD141272
T. Eisenbeiss, A. Seifahrt, M. Mugrauer +3
We search for stellar and substellar companions of young nearby stars to investigate stellar multiplicity and formation of stellar and substellar companions. We detect common prope…
Near-IR integral-field spectroscopy of the companion to GQ Lup
Andreas Seifahrt, Ralph Neuhaeuser, Peter H. Hauschildt +1
The first substellar companion of possibly planetary mass around a normal star, GQ Lup, has been directly imaged (Neuhaeuser et al., 2005). Besides the unknown formation history, t…
Detectability of planets in wide binaries by ground-based relative astrometry with AO
Ralph Neuhaeuser, Andreas Seifahrt, Tristan Roell +2
Many planet candidates have been detected by radial velocity variations of the primary star; they are planet candidates, because of the unknown orbit inclination. Detection of the…
The University of Hawaii Wide Field Imager (UHWFI)
Klaus W. Hodapp, Andreas Seifahrt, Gerard A. Luppino +8
The University of Hawaii Wide-Field Imager (UHWFI) is a focal compressor system designed to project the full half-degree field of the UH 2.2 m telescope onto the refurbished UH 8Kx…
New brown dwarf companions to dM(e) stars
Andreas Seifahrt, Markus Mugrauer, Manuela Wiese +2
We present new astrometric and spectroscopic data to confirm two new M/L dwarf systems, G124-62 and LHS5166, and discuss the nature of a third system (LP261-75). Age and thus mass…
Four new wide binaries among exoplanet host stars
M. Mugrauer, R. Neuhaeuser, A. Seifahrt +2
In our ongoing survey for wide (sub)stellar companions of exoplanet host stars we have found 4 new co-moving stellar companions of the stars HD114729, HD16141, HD196050 and HD21324…