Browsing by Author "Dreizler, S."

Now showing items 1-14 of 14

    • 2MASS J0516288+260738: Discovery of the first eclipsing late K + Brown dwarf binary system 

      Schuh, S.L.; Handler, G.; Drechsel, H.; Hauschildt, P.; Dreizler, S.; Medupe, R.; Karl, C.; Napiwotzki, R.; Kim, S.; Park, B.G.; Wood, M.; Paparo, M.; Szeidl, B.; Viraghalmy, G.; Zsuffa, D.; Hashimoto, O.; Kinugasa, K.; Taguchi, H.; Kambe, E.; Leibowitz, E.; Ibbetson, P.; Lipkin, Y.; Nagel, T.; Gohler, E.; Pretorius, M.L. (2003-11)
      We report the discovery of a new eclipsing system less than one arcminute south of the pulsating DB white dwarf KUV05134+2605. The object could be identified with the point source 2MASSJ0516288+260738 published by the Two ...

    • A candidate super-Earth planet orbiting near the snow line of Barnard's star 

      Ribas, I.; Tuomi, M.; Reiners, A.; Butler, R. P.; Morales, J. C.; Perger, M.; Dreizler, S.; Rodríguez-López, C.; Hernández, J. I. González; Rosich, A.; Feng, F.; Trifonov, T.; Vogt, S. S.; Caballero, J. A.; Hatzes, A.; Herrero, E.; Jeffers, S. V.; Lafarga, M.; Murgas, F.; Rodríguez, E.; Strachan, J. B. P.; Tal-Or, L.; Teske, J.; Toledo-Padrón, B.; Zechmeister, M.; Quirrenbach, A.; Amado, P. J.; Azzaro, M.; Béjar, V. J. S.; Barnes, J. R.; Berdiñas, Z. M.; Coleman, G.; Cortés-Contreras, M.; Crane, J.; Engle, S. G.; Guinan, E. F.; Haswell, C. A.; Henning, Th; Holden, B.; Jones, H. R. A.; Kaminski, A.; Kiraga, M.; Kürster, M.; López-González, M. J.; Montes, D.; Morin, J.; Ofir, A.; Pallé, E.; Rebolo, R.; Reffert, S.; Schweitzer, A.; Seifert, W.; Shectman, S. A.; Staab, D.; Street, R. A.; Mascareño, A. Suárez; Tsapras, Y.; Anglada-Escudé, G. (2018-11-15)
      Barnard’s star is a red dwarf, and has the largest proper motion (apparent motion across the sky) of all known stars. At a distance of 1.8 parsecs, it is the closest single star to the Sun; only the three stars in the α ...

    • The CARMENES search for exoplanets around M dwarfs. Characterization of the nearby ultra-compact multiplanetary system YZ Ceti 

      Stock, S.; Kemmer, J.; Reffert, S.; Trifonov, T.; Kaminski, A.; Dreizler, S.; Quirrenbach, A.; Caballero, J. A.; Reiners, A.; Jeffers, S. V.; Anglada-Escudé, G.; Ribas, I.; Amado, P. J.; Barrado, D.; Barnes, J. R.; Bauer, F. F.; Berdiñas, Z. M.; Béjar, V. J. S.; Coleman, G. A. L.; Cortés-Contreras, M.; Díez-Alonso, E.; Domínguez-Fernández, A. J.; Espinoza, N.; Haswell, C. A.; Hatzes, A.; Henning, T.; Jenkins, J. S.; Jones, H. R. A.; Kossakowski, D.; Kürster, M.; Lafarga, M.; Lee, M. H.; González, M. J. López; Montes, D.; Morales, J. C.; Morales, N.; Pallé, E.; Pedraz, S.; guez, E. Rodrí; Rodríguez-López, C.; Zechmeister, M. (2020-02-07)
      Context. The nearby ultra-compact multiplanetary system YZ Ceti consists of at least three planets, and a fourth tentative signal. The orbital period of each planet is the subject of discussion in the literature due to ...

    • Extremely Faint Blue-tail Stars in Centauri 

      Moehler, S.; Napiwotzki, R.; Sweigart, A.V.; Landsman, S.; Dreizler, S. (2002)

    • Extremely faint blue-tail stars in ω Centauri 

      Moehler, S.; Napiwotzki, R.; Sweigart, A.V.; Landsman, S.; Dreizler, S. (Astronomical Society of the Pacific, 2002)

    • A multiplanet system of super-Earths orbiting the brightest red dwarf star GJ 887 

      Jeffers, S. V.; Dreizler, S.; Barnes, J. R.; Haswell, C. A.; Nelson, R. P.; Rodríguez, E.; Lopez-Gonzalez, M. J.; Morales, N.; Luque, R.; Zechmeister, M.; Vogt, S. S.; Jenkins, J. S.; Palle, E.; Berdinas, Z. M.; Coleman, G. A. L.; Diaz, M. R.; Ribas, I.; Jones, H. R. A.; Butler, R. P.; Tinney, C. G.; Bailey, J.; Carter, B. D.; ~O'Toole, S.; Wittenmyer, R. A.; Crane, J. D.; Feng, F.; Shectman, S. A.; Teske, J.; Reiners, A.; Amado, P. J.; Anglada-Escude, G.; . (2020-06-26)
      The closet exoplanets to the Sun provide opportunities for detailed characterization of planets outside the Solar System. We report the discovery, using radial velocity measurements, of a compact multiplanet system of ...

    • NLTE spectral analysis of helium-rich sdO stars from the southern HK survey. 

      Drilling, J.S.; Napiwotzki, R.; Dreizler, S.; Heber, U.; Beers, T.C. (Astronomical Society of the Pacific, 1996)
      We have determined effective temperatures, surface gravities, and helium-to-hydrogen abundance ratios by fitting NLTE model atmospheres to high signal-to-noise- spectra of eight helium-rich sdO stars detected in the southern ...

    • NLTE Spectral Analysis of Iron Group Elements in the Hot Subluminous O-star BD+28 4211 

      Ramspeck, M.; Haas, S.; Napiwotzki, R.; Heber, U.; Deetjen, J.; Dreizler, S. (Astronomical Society of the Pacific, 2003)
      An analysis of UV spectra of BD+28circ4211 obtained with the STIS spectrograph onboard the HST is presented. The spectral analysis is based on NLTE model calculation, which deal with the lineblanketing of iron group elements ...

    • NO EVIDENCE for ACTIVITY CORRELATIONS in the RADIAL VELOCITIES of KAPTEYN'S STAR 

      Anglada-Escudé, G.; Tuomi, Mikko; Arriagada, P.; Zechmeister, M.; Jenkins, J. S.; Ofir, A.; Dreizler, S.; Gerlach, E.; Marvin, C. J.; Reiners, A.; Jeffers, S. V.; Butler, R. Paul; Vogt, S. S.; Amado, P. J.; Rodríguez-López, C.; Berdiñas, Z. M.; Morin, J.; Crane, J. D.; Shectman, S. A.; Díaz, M. R.; Sarmiento, L. F.; Jones, H. R A (2016-10-20)
      Stellar activity may induce Doppler variability at the level of a few m s-1 which can then be confused by the Doppler signal of an exoplanet orbiting the star. To first order, linear correlations between radial velocity ...

    • Rotation Velocities of DA White Dwarfs with Convective Atmospheres 

      Karl, C.; Heber, U.; Napiwotzki, R.; Dreizler, S.; Koester, D.; Reid, I.N. (Astronomical Society of the Pacific, 2005)
      The sharp H® NLTE line cores of hydrogen rich (DA) white dwarfs allow their projected rotational velocities to be determined. High resolution optical spectra of 22 stars obtained with the Keck I telescope are matched by ...

    • Rotation velocities of white dwarfs. III. DA stars with convective atmospheres 

      Karl, C.; Napiwotzki, R.; Heber, U.; Dreizler, S.; Koester, D.; Reid, I.N. (2005-05)

    • Spectral analysis of sdB Stars from the Hamburg Quasar Survey 

      Edelmann, H.; Heber, U.; Hagen, H.J.; Dreizler, S.; Napiwotzki, R.; Engels, D.; Lemke, M. (2003-03)

    • Subluminous O Stars from the ESO Supernova Progenitor Survey - Observation versus Theory 

      Stroeer, A.; Heber, U.; Lisker, T.; Napiwotzki, R.; Dreizler, S. (Astronomical Society of the Pacific, 2005)
      The ESO Supernova Progenitor Survey (SPY) has identified 58 (mostly helium-rich) subluminous O stars. We use the Balmer line strength to distinguish sdO from He-sdO (no Balmer lines) and present the results of the analyses ...

    • Two planets around Kapteyn's star: a cold and a temperate super-Earth orbiting the nearest halo red dwarf 

      Anglada-Escude, Guillem; Arriagada, P.; Tuomi, Mikko; Zechmeister, M.; Jenkins, J. S.; Ofir, A.; Dreizler, S.; Gerlach, E.; Marvin, C. J.; Reiners, A.; Jeffers, S. V.; Butler, R.P.; Vogt, S. S.; Amado, P. J.; Gerlach, E.; Rodríguez-López, C.; Berdiñas, Z. M.; Morin, J.; Crane, J. D.; Shectman, S. A.; Thompson, Ian B.; Diaz, M.; Rivera, E.; Sarmiento, L. F.; Jones, Hugh (2014-09-01)
      Exoplanets of a few Earth masses can be now detected around nearby low-mass stars using Doppler spectroscopy. In this Letter, we investigate the radial velocity variations of Kapteyn's star, which is both a sub-dwarf M-star ...