12 papers · 1 filter
Direct detection of exo-planets: GQ Lupi
Ralph Neuhaeuser, Eike Guenther, Peter Hauschildt
We present a comparison of our VLT/NACO K-band spectrum of the GQ Lupi companion with the new GAIA-dusty model atmosphere grid for T=2000 and 2900 K and log g from 0 to 4. Then, we…
VLT spectra of the companion candidate Cha Ha 5/cc 1
Ralph Neuhaeuser, Eike Guenther, Wolfgang Brandner
We obtained optical and infrared spectra of Cha Ha 5/cc 1, a faint possibly sub-stellar companion candidate next to the M6-type brown dwarf candidate Cha Ha 5 in Cha I, using FORS1…
The joint XMM-Newton and Chandra view of YY Gem
B. Stelzer, V. Burwitz, R. Neuhaeuser +2
We have observed the flare star YY Gem simultaneously with XMM-Newton and Chandra as part of a multi-wavelength campaign aiming at a study of variability related to magnetic activi…
Observing the planet formation time-scale by ground-based direct imaging of planetary companions to young nearby stars: Gemini/Hokupa'a image of TWA-5
Ralph Neuhaeuser, Dan Potter, Wolfgang Brandner
Many extra-solar planets and a few planetary systems have been found indirectly by small periodic radial velocity variations around old nearby stars. The orbital characteristics of…
X-ray emission and variability of young, nearby stars
B. Stelzer, R. Neuhaeuser
X-ray emission has played a major role in the recent identification of several groups of young, nearby stars. The ROSAT All-Sky Survey (RASS) is due to its spatial completeness an…
Radial-Velocity Monitoring of Members and Candidate Members of the TW Hydrae Association
Guillermo Torres, Ralph Neuhaeuser, David W. Latham
We present our spectroscopic measurements of the radial velocity, effective temperature, and projected rotational velocity of several of the known members of the TW Hya association…