Science Archives Publication System

The Optical Spectrum of the Geminga Pulsar

DOI: 10.1086/311179 Bibcode: 1998ApJ...494L.211M

Halpern, Jules P.; Schiminovich, David; Martin, Christopher

We obtained an optical spectrum of the isolated pulsar Geminga at the Keck Observatory. The optical object is at the limit of spectroscopic capability of any telescope, with a continuum flux that is ~0.5% of the dark sky on Mauna Kea. With particular attention paid to the dominant systematics of sky subtraction in our observing and analysis method…

1998 • The Astrophysical Journal

eHST 40

X-ray activity and evolutionary status of late-type giants

Bibcode: 1998A&A...335..591S

Schmitt, J. H. M. M.; Schroeder, K. -P.; Huensch, M.

We study the evolution of stellar activity in a volume-limited sample of single giants within 35 pc distance from the Sun as measured by the amount of soft X-ray emission. This sample of 36 stars is assumed to be complete for absolute magnitude M_V la 3.0 and for X-ray luminosities L_x ga 1.5 x 10(28) erg s(-1) . We use ROSAT data to determine ste…

1998 • Astronomy and Astrophysics

Hipparcos 40

The Cepheid period-luminosity zero-point from radial velocities and HIPPARCOS proper motions

DOI: 10.1046/j.1365-8711.1998.01912.x Bibcode: 1998MNRAS.298L..43F

Pont, Frederic; Feast, Michael; Whitelock, Patricia

A value for the zero-point (rho) of the Cepheid period-luminosity relation, <M_V>=2.81log P+rho, is deduced by comparing the value of the Oort constant, A, derived from radial velocities with that derived from Hipparcos proper motions. We find in this way that rho=-1.47+/-0.13, in excellent agreement with the value derived from Hipparcos tri…

1998 • Monthly Notices of the Royal Astronomical Society

Hipparcos 40

Lyman-alpha observations of comet Hyakutake with SWAN on SOHO

DOI: 10.1016/S0032-0633(97)00179-7 Bibcode: 1998P&SS...46..555B

Schmidt, W.; Bertaux, J. L.; Lallement, R. +7 more

The SWAN instrument on board SOHO is a Lyman-α (Lα) photometer able to map the sky intensity with a resolution of 1°, and a capability of microstepping (0.1°). SWAN is primarily devoted to the study of the large scale distribution of solar wind from its imprints on the interplanetary sky background, but was in addition extensively used to map the …

1998 • Planetary and Space Science

SOHO 40

New variable chemically peculiar stars identified in the HIPPARCOS archive

DOI: 10.1051/aas:1998305 Bibcode: 1998A&AS..133....1P

Paunzen, E.; Maitzen, H. M.

Since variability of chemically peculiar (CP) stars plays an important role for the astrophysical explanation of their outstanding behaviour, we have identified new variable CP stars listed in Renson's catalogue using the extensive Hipparcos Variability Annex. From the 293 objects found, 33 were excluded because they are no CP stars and/or have no…

1998 • Astronomy and Astrophysics Supplement Series

Hipparcos 40

Infrared spectroscopy of Sakurai's object

DOI: 10.1046/j.1365-8711.1998.01898.x Bibcode: 1998MNRAS.298L..37E

Eyres, S. P. S.; Salama, A.; Evans, A. +2 more

We present near (ground-based) and far (ISO) infrared spectroscopy of Sakurai's object. As in the case of the optical spectrum, between 1996 and 1997 April the near-infrared spectrum underwent a dramatic change to later spectral type, and there is some evidence that the spectrum continued to evolve during 1997. Molecular features of carbon-bearing…

1998 • Monthly Notices of the Royal Astronomical Society

ISO 40

The new gravitational lens system B1030+074

DOI: 10.1046/j.1365-8711.1998.01804.x Bibcode: 1998MNRAS.300..649X

Koopmans, L. V. E.; Browne, I. W. A.; Wilkinson, P. N. +6 more

We report the discovery of a new double-image gravitational lens system, B1030+074, which was found during the Jodrell Bank-VLA Astrometric Survey (JVAS). We have collected extensive radio data on the system using the VLA, MERLIN, the EVN and the VLBA, and optical observations using WFPC2 on the HST. The lensed images are separated by 1.56 arcsec …

1998 • Monthly Notices of the Royal Astronomical Society

eHST 39

Solar Wind Consequences of a Coronal Hole Density Profile: Spartan 201-03 Coronagraph and Ulysses Observations from 1.15 R_solar to 4 AU

DOI: 10.1086/311371 Bibcode: 1998ApJ...499L.215G

Guhathakurta, Madhulika; Fisher, Richard

Spartan 201 is a small shuttle-launched and -retrieved satellite, whose mission is to study the origins of the solar wind. It carries on board two instruments, the Ultraviolet Coronal Spectrometer and the White-Light Coronagraph. The third mission of the Spartan 201 (1995 September 7-10) spacecraft was to provide a solar context for the in situ pa…

1998 • The Astrophysical Journal

Ulysses 39

HST spatially resolved spectra of the accretion disc and gas stream of the nova-like variable UX Ursae Majoris

DOI: 10.1046/j.1365-8711.1998.01712.x Bibcode: 1998MNRAS.298.1079B

Horne, Keith; Hubeny, Ivan; Long, Knox S. +3 more

Time-resolved eclipse spectroscopy of the nova-like variable UX UMa obtained with the HST/FOS on 1994 August and November is analysed with eclipse mapping techniques to produce spatially resolved spectra of its accretion disc and gas stream as a function of distance from the disc centre. The inner accretion disc is characterized by a blue continuu…

1998 • Monthly Notices of the Royal Astronomical Society

eHST 39

The ¹¹B/¹⁰B Ratio of Local Interstellar Diffuse Clouds

DOI: 10.1086/305235 Bibcode: 1998ApJ...494..614L

Sofia, Ulysses J.; Federman, S. R.; Lambert, David L. +3 more

The isotopic ratio ¹¹B/¹⁰B of gas in diffuse interstellar clouds toward ζ Oph, κ Ori, and δ Sco is measured using HST/Goddard High Resolution Spectrograph echelle spectra of the B II 1362 Å line. To within the errors of measurement, the three lines of sight give identical results for a mean value of ¹¹B/¹⁰

1998 • The Astrophysical Journal

eHST 39