Search Publications
Do All BA II Stars Have White Dwarf Companions?
Carpenter, Kenneth; Robinson, Richard; Böhm-Vitense, Erika +2 more
With the Hubble Space Telescope (HST) and the Goddard High Resolution Spectrograph (GHRS) we have observed four barium stars, three mild barium stars, and one weak G-band star in the ultraviolet spectral region. One barium star was observed with HST and the Space Telescope Imaging Spectrograph (STIS). The aim was to check the hypothesis that all t…
Detection of the Entropy of the Intergalactic Medium: Accretion Shocks in Clusters, Adiabatic Cores in Groups
Tozzi, Paolo; Norman, Colin; Scharf, Caleb
The thermodynamics of the diffuse, X-ray-emitting gas in clusters of galaxies is linked to the entropy level of the intracluster medium. In particular, models that successfully reproduce the properties of local X-ray clusters and groups require the presence of a minimum value for the entropy in the center of X-ray halos. Such a minimum entropy is …
Observations of the Trans-Neptunian Objects 1993 SC and 1996 TL66 with the Infrared Space Observatory
Jorda, L.; Rauer, H.; Keller, H. U. +7 more
Observations at 90 µm of the trans-Neptunian objects (TNOs), 1993 SC and 1996 TL66, using the Infrared Space Observatory (ISO) are reported. Five individual observations of 1993 SC were acquired giving a 2.7 σ detection (a confidence level of 99.6%). The signal level of 11.46+/-4.24 mJy has been modeled using a standard thermal mo…
Analysis of the Hipparcos Measurements of HD 10697: A Mass Determination of a Brown Dwarf Secondary
Mazeh, Tsevi; Zucker, Shay
HD 10697 is a nearby main-sequence star around which a planet candidate has recently been discovered by means of radial velocity measurements (Vogt et al.). The stellar orbit has a period of about 3 yr, the secondary minimum mass is 6.35 Jupiter masses (MJ), and the minimum semimajor axis is 0.36 mas. Using the Hipparcos data of HD 1069…
The Pleiades, Map-based Trigonometric Parallaxes of Open Clusters. V.
Han, Inwoo; Gatewood, George; de Jonge, Joost Kiewiet
The Multichannel Astrometric Photometer and Thaw Refractor (Thaw/MAP) of the University of Pittsburgh's Allegheny Observatory have been used to determine the trigonometric parallax of the Pleiades star cluster. The parallax determined, 0.00764" with a standard error of +/-0.00043" (corresponding to a distance modulus of 5.59+/-0.12 mag) places the…
Discovery of Parsec-sized Dust Shells around AFGL 2688 and AFGL 618
Meixner, M.; Knapp, G. R.; Speck, A. K.
We present ISOPHOT linear scans of two carbon-rich proto-planetary nebulae, AFGL 2688 and AFGL 618. The 53'×3' scans were made with the ISO AOT PHT32 using the 120 and 180 µm filters. Both these objects appear to have very bright central point sources together with extremely extended (radius ~350"-400") dust shells with…
Hubble Space Telescope Spectroscopy of Spot 1 on the Circumstellar Ring of SN 1987A
Filippenko, Alexei V.; Pun, C. S. J.; Garnavich, Peter +15 more
We present ultraviolet and optical spectra of the first bright spot (P.A.=29deg) on SN 1987A's equatorial circumstellar ring taken with the Space Telescope Imaging Spectrograph. We interpret this spot as the emission produced by radiative shocks that occur where the supernova blast wave strikes an inward protrusion of the ring. The obse…
Comparison of Frequencies and Rotational Splittings of Solar Acoustic Modes of Low Angular Degree from Simultaneous MDI and GOLF Observations
Kosovichev, A. G.; Henney, C. J.; Scherrer, P. H. +8 more
During the years 1996 through 1998 the Michelson Doppler Imager (MDI) and the Global Oscillations at Low Frequency (GOLF) experiments on the Solar and Heliospheric Observatory (SOHO) mission have provided unique and nearly uninterrupted sequences of helioseismic observations. This paper describes the analysis carried out on power spectra from 759 …
Unavoidable Selection Effects in the Analysis of Faint Galaxies in the Hubble Deep Field: Probing the Cosmology and Merger History of Galaxies
Yoshii, Yuzuru; Totani, Tomonori
We present a detailed analysis of the number count and photometric redshift distribution of faint galaxies in the Hubble Deep Field (HDF), paying special attention to selection effects, including the cosmological dimming of the surface brightness of galaxies, under the observational conditions employed in this field. We find a considerably differe…
Infrared Space Observatory Spectroscopy of HH 7-11 Flow and Its Redshifted Counterpart
Ceccarelli, Cecilia; Giannini, Teresa; Nisini, Brunella +7 more
We have used the two spectrometers on the Infrared Space Observatory to observe the HH 7-11 flow, its redshifted counterpart, and the candidate exciting source SVS 13 in the star formation region NGC 1333. We detect atomic ([O I] 63 µm, [O I] 145 µm, [Si II] 34.8 µm, [C II] 158 µm) and molecular (H2, CO, H2<…