Haute-Provence Observatory Research Articles

The cluster of galaxies Abell 970

We present a dynamical analysis of the galaxy cluster Abell 970 based on a new set of radial velocities measured at ESO, Pic du Midi and Haute-Provence observatories. Our analysis indicates that this cluster has a substructure and is out of dynamical equilibrium. This conclusion is also supported by differences in the positions of the peaks of the surface density distribution and X-ray emission, as well as by the evidence of a large scale velocity gradient in the cluster. We also found a discrepancy between the masses inferred with the virial theorem and with the X-ray emission, what is expected if the galaxies and the gas inside the cluster are not in hydrostatic equilibrium. Abell 970 has a modest cooling flow, as is expected if it is out of equilibrium as suggested by Allen (1998). We propose that cooling flows may have an intermittent behavior, with phases of massive cooling flows being followed by phases without significant cooling flows after the acretion of a galaxy group massive enough to disrupt the dynamical equilibrium in the center of the clusters. A massive cooling flow will be established again, after a new equilibrium is achieved.

The B[e] Star MWC 84 (CI Cam)

The star MWC 84 (CI Cam) was first discovered to be an emission line object classified Bep (Merrill & Burwell, 1933), then classified as a symbiotic star and finally identified as the possible optical counterpart of the X-ray transient XTE J0421+560 (Wagner & Starrfield, 1998)We have observed MWC 84 at the Haute Provence Observatory (CNRS) with a resolution of about 1.3 Å in 1992 (wavelength regions Hα and near infrared), 1998 and 1999 (from 4080 to 8880 Å).

B[e] stars

On the basis of spectroscopic CCD material obtained at the Haute Provence Observatory, we provide line identifications and equivalent width measurements in the wavelength region 4095-8935 A of the spectrum of MWC 342. Two hundred eighty emission features are identified and eighteen absorption features. Nine interstellar bands could be identified. Some of the remaining absorption lines correspond to a B0 type star. The cooler emission lines correspond to a spectrum of an early A-type star. The temperatures derived from both spectral types (29 000 and 9 000 K) are in excellent agreement with the temperatures derived by photometrists.

B[e] stars

On the basis of spectroscopic CCD material obtained at the Haute Provence Observatory, we provide line identifications and equivalent width measurements in the wavelength region 4086-8780 Å of the spectrum of MWC 17. Four hundred emission features are identified and seventeen absorption features. Six interstellar bands could be identified. Some of the remaining absorption lines correspond to an early B type star. The emission lines of the envelope correspond approximately to a spectrum of an A0 type star. The star presents variations in the equivalent widths of its lines which correspond to a factor of about two over a time scale of days.

B[e] stars

On the basis of spectroscopic CCD material obtained at the Haute Provence Observatory, we provide line identifications and equivalent width measurements in the wavelength region 4100 - 8900 A of the spectrum of MWC 297. About two hundred features are identified, almost exclusively emission lines. Only one interstellar feature could be identified ( λ 6613) a fact which contrasts with the eigth magnitudes of extinction found by photometrists. The spectrum of the underlying star corresponds probably to a late O or early B-type object. The cooler emission lines correspond to a spectrum of a middle A-type star. Analogies with other stars observed in this series of papers are examined.

CH Cygni 1987-89: The inactive state as a precursor to the new outburst

In order to help answering the question generally posed for symbiotic stars: are the apparently inactive periods quiescent at all, or should they be regarded merely as a transition between adjacent outbursts, we tried to establish correlation between the subtle phenomena in the time evolution of the cool giant's photosphere and emission line profiles of the symbiotic star CH Cygni during the period 1987-89. Optical spectra of this star in its inactive state taken at the Haute Provence Observatory as well as the spectra of late type giant's of the same spectral type have been used. The comparison of the results obtained suggests that the time evolution of the physical parameters of CH Cyg reflect the symbiotic phenomena rather than the intrinsic variability of the cool component. The time behaviour of the Balmer emission line profiles rules out the general validity of the established models. An acceptable model valid at least for the observed period has been proposed. According to it, an envelope of variable optical thickness surrounds the hot component. The development of its inner radius, of and line profiles and of the nebular line leads to the conclusion that the inactive state is not stationary, but is gradually evolving in time toward the new activity of the star.

B[e] stars

On the basis of spectroscopic CCD material obtained at the Haute Provence Observatory, we provide line identifications and equivalent width measurements in the wavelength region 3738-10232 A of the spectrum of HD 50138 Over two hundred features are identified and a comparison of our results with those of other authors is provided. We also discuss the variability of the lines using equivalent widths and descriptions of the line spectrum. We attribute as a best compromise a spectral type of B 5 III. We conclude that the gaseous shell surrounding the star has a temperature of the order of 10 000 K and that its distance to the star is of the order of two stellar radii. We discuss the relation of this star to others previously analyzed and warn against hasty generalizations.

Spectroscopic Radial Velocities: Photospheric Lineshifts Calibrated By Hipparcos

Wavelengths of stellar spectral lines depend not only on the star’s motion. Until recently, accurate studies of shifts not caused by radial motion were feasible only for the Sun. Solar lineshifts are interpreted as gravitational redshift (636 m/s) and convective blueshifts (~ 400 m/s; caused by velocity-brightness correlations). In other stars, such effects may be greater (Dravins & Nordlund 1990). Accurate astrometric radial velocities are now available from Hipparcos (Dravins et al. 1997a; 1997b), permitting studies of such shifts also in some other stars.For such stars in the open clusters of Hyades, Ursa Major and Coma Berenices, a spectroscopic program is in progress, analyzing wavelength shifts in groups of lines with different strengths, excitation potentials, etc., using the ELODIE high-precision radial-velocity instrument (Baranne et al. 1996) at Haute-Provence Observatory.

Rotational properties of main belt asteroids: photoelectric and CCD observations of 15 objects

In this paper we present the results of several observational campaigns carried out during 1996 at the 1.2 m telescope of the Haute Provence Observatory (France) and at the 1.5m Danish, 0.9m Dutch, 0.6m Bochum and 0.5m telescopes of the European Southern Observatory (ESO, La Silla, Chile), in order to enlarge the available sample of know asteroid rotational periods. A total of 64 single night lightcurves for 15 asteroids were obtained. The rotational periods have been determined for 12 objects, with different quality code: 424 Gratia ( P syn = 19.47 h), 440 Theodora ( P syn = 4.828 h), 446 Aeternitas ( P syn = 15.85 h), 491 Carina ( P syn = 14.87 h), 727 Nipponia ( P syn = 4.6 h), 732 Tjilaki ( P syn = 12.34 h), 783 Nora ( P syn = 34.4 h), 888 Parysatis ( P syn = 5.49 h), 1626 Sadeya ( P syn = 3.438 h), 2209 Tianjin ( P syn = 9.47 h), 2446 Lunacharsky ( P syn = 3.613 h) and 3776 Vartiovuori ( P syn = 7.7 h). For 1246 Chaka, 1507 Vaasa and 1994 Shane the complete rotational phase was not covered and for two of them it was possible to find only an indication of the rotational period.

B[e] stars

On the basis of spectroscopic CCD material obtained at the Haute Provence Observatory, we provide line identifications and equivalent width measurements in the wavelength regions 3750-5112 and of the spectrum of HD 45677. Over 235 features are identified and a comparison of our results with those of other authors is provided. We also discuss the variability of the lines using equivalent widths and the line spectrum. We conclude that the gaseous shell surrounding the star has a temperature of the order of 7000 K and that its distance to the star is less than ten stellar radii. We discuss the similarity of this star to other stars previously analyzed.

CCD Polarimetric Imaging Of Comet Hale-Bopp (C/1995 O1)

Polarimetric observations of the light scattered by dust have been carried out at Pic-du-Midi Observatory with the 2 m telescope in June and September–October 1996, and at Haute-Provence Observatory with the 0.80 m telescope in April 1997. They cover a total number of 11 nights and a large (6.9°–47.7°) phase angle range. The spatial resolution allows to underline structures in the coma, as well in the brightness images as in the polarization maps, with a correlation between the regions of bright structures and the regions of higher polarization. A clear difference appears between the sunward and antisunward side, with higher polarization on the antisunward side. The phase angle coverage allows us to obtain a polarimetric phase curve for the whole coma and to compare it with other cometary phase curves. The degree of polarization is higher for Hale-Bopp than for the comets previously observed.

Evolution of Dust Shells and Jets in the Inner Coma of Comet C/1995 O1 (Hale-Bopp)

Comet Hale-Bopp was observed with the 80 cm reflector + CCD at the Haute-Provence observatory (OHP) and with the 62 cm reflector + CCD at the Saint-Veran observatory (Queyras, France). The morphology of the shells was followed from their first appearence on 1997 Jan. 30, until their disappearance on May 9. These shells spread from the nucleus region with a velocity in agreement with a nuclear rotation period of about 11.33 hours. We report also a short and bright dust ejection on May 8. CN images show a long spiral jet in the tailward side invisible on continuum images. The circumnuclear structures have been followed at Saint-Veran from Apr. 5 to Apr. 11, 1997 with a high spatial resolution (200 km/pixel). We have followed the emergence of a recurrent linear polar jet. Measurements of its expansion show a constant acceleration of material with typical expansion velocity of 1 km/s. The CCD frames show the interconnection between spiral jets and the successive shells.

Fullerenes in space

The discovery and synthesis of fullerenes led to the hypothesis that they may be present and stable in interstellar space. Fullerenes have been reported in an impact crater on the LDEF spacecraft. Investigations of fullerenes in carbonaceous meteorites have yielded only small upper limits. Fullerene compounds and their ions could be interesting carrier molecules for some of the “diffuse interstellar bands” (DIBs), a long standing mystery in astronomy. We have detected two new diffuse bands that are consistent with laboratory measurements of the C 60 + , as first evidence for the largest molecule ever detected in space. Criteria for this identification are discussed. The inferred abundance (up to 0.9 % of cosmic carbon locked in C 60 + ) suggests that fullerenes may play an important role in interstellar chemistry. We present new observations ∗ ∗ Based on observations obtained at Haute Provence Observatory OHP, Canada France Hawaii CFHT and ESO La Silla on DIB substructures consistent with fullerene compounds, and the search for neutral C 60 in the diffuse medium.

B[e] stars. III. MWC 645

We analyse spectroscopic CCD material obtained at the Haute Provence Observatory. We provide identifications and equivalent width measurements in the wavelength region 3740-8790. About 350 emissions lines were measured and about 88 of them were identified. A comparison of our results with those of other authors is provided, as well as a table of elements identified in the spectrum of this star. The pattern of elements present is analogous to that of a late B-type star, but some exceptions are noted, such as the absence of Ne and Mg lines and the presence of K, Cu and Zr lines which appear usually in later type stars. We review the little which is known concerning this object and we also present a quantitative account of the variations in equivalent widths. The observations indicate that the spectrum is highly variable, so that in two different years only half of the lines appear on both spectra. Furthermore variations by at least a factor of two in the equivalent widths are present in many lines. The radial velocity derived from the emission lines (-76 km/s) corresponds to that of the shell which probably has a velocity of about 50 km/s with respect to the underlying star.

B[e] stars. II. MWC 349 A

We analyse spectroscopic CCD material obtained at the Haute Provence Observatory. We provide line identications and equivalent width measurements in the wavelength region 3700 8790 A. Over 300 emission features are identied and a comparison of our results with those of other authors is provided, as well as a table of all elements which have been identied in the spectrum of the object. The pattern of elements present is analogous to that of B-type stars, but some exceptions are noted, such as the absence of C, Al and Mn. We review the present knowledge of the spectrum variability of MWC 349 A. The observations indicate that the equivalent widths of the lines of many elements vary by factors of up to two. We also provide a list of diuse interstellar features observed. The latter lead to an average (B V ) excess of about two magnitudes, which is less than what is expected for an object having an interstellar extinction of 10 11 magnitudes. ??

Total ozone determination by infrared heterodyne spectrophotometry

A CO 2 Laser Heterodyne Spectrophotometer (L.H.S.) has been used to record very high resolution (5 MHz) solar spectra. Observations of atmospheric ozone were made at Reims (France) (located 49°14′ North, 4°4′ East), during May 1990. The spectral data have been inverted by a non-linear least squares method written in the laboratory, to yield a total column amount of zone. The results are compared with data obtained by Dobson Spectrophotometer at the Observatory of Haute Provence (O.H.P.), France (located 43°56′ North, 5°4′ East).

Rotational properties of asteroids: CCD observations of nine small asteroids

The observational programme on small asteroids (diameter less than about 50 km) is continued to enlarge the available dataset of small asteroids. The results are presented of CCD observations of nine small asteroids ( D≤23 km), performed in France with the 1.2 m telescope at Haute Provence Observatory and with the 2 m telescope at Pic du Midi Observatory. A total of 27 single night lightcurves for nine asteroids were obtained. All the objects were observed for the first time and rotational periods have been determined for all of the observed asteroids: 1992 Galvarino ( P syn = 7 h.004), 2419 Moldavia ( P syn = 2 h.412), 2921 Sophocles ( P syn = 4 h.778), 3247 Di Martino ( P syn = 5 h.445), 3623 Chaplin ( P syn = 8 h.361), 3986 Rozhkovskij ( P syn = 4 h.26), 4436 1983 EX ( P syn = 6 h.656), 5046 1981 DQ ( P syn = 6 h.050) and 1992 YG3 ( P syn = 8 h.91).

B[e] stars. I. HD 51585 (=OY Gem)

We analyse CCD spectroscopic material obtained at the Haute Provence Observatory between 1990 and 1993, covering the wavelength region 3800-11000 A. 320 emission lines were measured and identified. Of these about 40% correspond to permitted or forbidden lines of ionized iron. Many forbidden lines (20% of the total) are present, including many classic nebular lines. We also provide a comparison of our results with those of other authors. The equivalent width measurements permit to follow in detail the variations of the lines of several elements over the three years and to compare them to variations reported by other authors. On our material the largest variations correspond to helium, which varied by a factor of two and are not in phase with the variations of hydrogen. Many helium lines exhibit P Cyg type profiles, indicating strong outflow of matter from the star. The lines of other elements follow either the variations of the helium or of the hydrogen lines. The radial velocity varies over the years, with an amplitude of more than 60 km/s.

Validation of UARS Microwave Limb Sounder temperature and pressure measurements

The accuracy and precision of the Upper Atmosphere Research Satellite (UARS) Microwave Limb Sounder (MLS) atmospheric temperature and tangent‐point pressure measurements are described. Temperatures and tangent‐point pressure (atmospheric pressure at the tangent height of the field of view boresight) are retrieved from a 15‐channel 63‐GHz radiometer measuring O2 microwave emissions from the stratosphere and mesosphere. The Version 3 data (first public release) contains scientifically useful temperatures from 22 to 0.46 hPa. Accuracy estimates are based on instrument performance, spectroscopic uncertainty and retrieval numerics, and range from 2.1 K at 22 hPa to 4.8 K at 0.46 hPa for temperature and from 200 m (equivalent log pressure) at 10 hPa to 300 m at 0.1 hPa. Temperature accuracy is limited mainly by uncertainty in instrument characterization, and tangent‐point pressure accuracy is limited mainly by the accuracy of spectroscopic parameters. Precisions are around 1 K and 100 m. Comparisons are presented among temperatures from MLS, the National Meteorological Center (NMC) stratospheric analysis and lidar stations at Table Mountain, California, Observatory of Haute Provence (OHP), France, and Goddard Spaceflight Center, Maryland. MLS temperatures tend to be 1–2 K lower than NMC and lidar, but MLS is often 5 – 10 K lower than NMC in the winter at high latitudes, especially within the northern hemisphere vortex. Winter MLS and OHP (44°N) lidar temperatures generally agree and tend to be lower than NMC. Problems with Version 3 MLS temperatures and tangent‐point pressures are identified, but the high precision of MLS radiances will allow improvements with better algorithms planned for the future.

CCD observations: rotational properties of 13 small asteroids

About 10 years ago our group in the Meudon Observatory started an observational program on small asteroids (diameter ⩽ 50 km) in order to enlarge the knowledge of this size range objects. The results of three observational runs are reported, carried out in January 1993, August 1993 and August 1994, with the 1.2 m telescope of the Haute-Provence Observatory and with the 2.0 m telescope of the Pic du Midi Observatory, both in France. Thirteen asteroids were observed; for 9 of them the rotational period was determined with different quality codes and the composite lightcurves obtained are presented. For four asteroids (3017 Petrovic ( P syn = 4.069±0.006 h), 4045 1953RG ( P syn = 9.764±0.003 h), 4483 Petofi ( P syn = 4.480±0.013 h) and 4628 Laplace ( P syn = 9.011±0.005 h)) an unambiguous period is determined. For three of them (4224 Susa ( P syn = 7.78±0.01 h), 4423 1949GH ( P syn = 10.51±0.01 h), and 5104 1986RU5 ( P syn = 6.14±0.01) a reasonably secure result is obtained. For two (3485 Barucci ( P syn = 14.65±0.06 h) and 3909 Gladys ( P syn = 6.83±0.01 h)) a tentative result is given. For the others (1783 Albitskij, 4164 Shilov, 4232 1977CD, and 4867 Polites) the single-night lightcurves are reported.