Robert P. Stefanik

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We present spatially resolved spectra observed with the Space Telescope Imaging Spectrograph on the Hubble Space Telescope of the upper chromosphere and dust envelope of α Orionis (M2 Iab). In the fall of 2002 a set of five high-resolution near-UV spectra was obtained by scanning at intensity peak-up position and four off-limb target positions up to one(More)
We present orbital solutions for three low-amplitude spectroscopic binaries discovered in a sample of 20 solar-type IAU radial-velocity standard stars observed with the Digital Speedometers at the Harvard-Smithsonian Center for Astrophysics. We update the orbital solutions for HD 114762 and HD 140913, and present a preliminary new solution for HD 29587. For(More)
The abundance of heavy elements (metallicity) in the photospheres of stars similar to the Sun provides a 'fossil' record of the chemical composition of the initial protoplanetary disk. Metal-rich stars are much more likely to harbour gas giant planets, supporting the model that planets form by accumulation of dust and ice particles. Recent ground-based(More)
With “Earth 2000” technology we could generate a directed laser pulse that outshines the broadband visible light of the Sun by four orders of magnitude. This is a conservative lower bound for the technical capability of a communicating civilization; optical interstellar communication is thus technically plausible. We have built a pair of systems to detect(More)
We report on the latest discovery of the HATNet project; a very hot giant planet orbiting a bright (V = 10.5) star with a small semi-major axis of a = 0.0377± 0.0005AU. Ephemeris for the system is P = 2.2047299 ± 0.0000040 days, mid-transit time E = 2, 453, 790.2593 ± 0.0010 (BJD). Based on the available spectroscopic data on the host star and photometry of(More)
We report the detection of a planet whose orbit surrounds a pair of low-mass stars. Data from the Kepler spacecraft reveal transits of the planet across both stars, in addition to the mutual eclipses of the stars, giving precise constraints on the absolute dimensions of all three bodies. The planet is comparable to Saturn in mass and size and is on a nearly(More)
Instituto de Astrof́ısica de Canarias, 38200 La Laguna, Tenerife, SPAIN High Altitude Observatory/National Center for Atmospheric Research, 3450 Mitchell Lane, Boulder, CO 80307 USA Harvard-Smithsonian Center for Astrophysics, 60 Garden St., Cambridge, MA 02138 USA University of Pittsburgh, Dept. of Physics & Astronomy, Pittsburgh, PA 15260 USA Lowell(More)
We present optical and near-infrared photometry and spectroscopy of the type Ia SN 1998bu in the Leo I Group galaxy M96 (NGC 3368). The data set consists of 356 photometric measurements and 29 spectra of SN 1998bu between UT 1998 May 11 and July 15. The well-sampled light curve indicates the supernova reached maximum light in B on UT 1998 May 19.3 (JD(More)
We show that the very close-by (19 pc) K0 star HD 189733, already found to be orbited by a transiting giant planet, is the primary of a double-star system, with the secondary being a midM dwarf with projected separation of about 216 AU from the primary. This conclusion is based on astrometry, proper motion and radial velocity measurements, spectral type(More)
We present UBVRI photometry of 44 type-Ia supernovae (SN Ia) observed from 1997 to 2001 as part of a continuing monitoring campaign at the Fred Lawrence Whipple Observatory of the Harvard-Smithsonian Center for Astrophysics. The data set comprises 2190 observations and is the largest homogeneously observed and reduced sample of SN Ia to date, nearly(More)