Une étude épidémiologique de la bronchite chronique à Genève

Rufener-Press, C.; Rey, P.; Press, P

doi:10.1159/000193057

Cited by 15 publications

(12 citation statements)

References 27 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…From May 30 to November 5, 2002, HD 192263 has been measured 187 times in the G photometric system (Golay 1980) with the photoelectric photometer P7 (Burnet & Rufener 1979), completely refurbished in 2001 and mounted on the 120-cm Belgian M telescope in La Palma (IAC, Canary Islands, Spain). The global photometric reduction procedure is described in Rufener (Rufener 1964(Rufener , 1985. However, in this particular case, two additional comparison stars, HD 194953 (G8 III) and HD 196712 (B7 III) have been systematically measured together with HD 192263, in order to improve the final data set.…”

Section: Photometrymentioning

confidence: 99%

The CORALIE survey for southern extra-solar planets

Santos¹,

Udry²,

Mayor³

et al. 2003

A&A

View full text Add to dashboard Cite

Abstract. The presence of a planet around the K dwarf HD 192263 was recently called into question by the detection of a periodic photometric signal with the same period as the one observed in radial velocity. In this paper, we investigate this possibility, using a combination of radial-velocity, photometry, and bisector measurements obtained simultaneously. The results show that while the observed radial-velocity variation is always very stable in phase, period, and amplitude, the photometric signal changes with time. The combined information strongly suggests that the observed radial-velocity variation is being produced by the presence of a planet, as firstly proposed. The photometric variations are either not connected to the planetary companion, or can eventually be induced by the interaction between the planet and the star. Finally, the radial-velocity data further show the presence of a long term trend, whose origin, still not clear, might be related to the presence of another companion to the system.

show abstract

Section: Photometrymentioning

confidence: 99%

The CORALIE survey for southern extra-solar planets

Santos¹,

Udry²,

Mayor³

et al. 2003

A&A

View full text Add to dashboard Cite

show abstract

“…The data set denoted 1989a was obtained in the Geneva photometric system (Golay 1980) with the photometer P7 (Burnet & Rufener 1979) on the 70 cm Swiss telescope; reduction procedures are described by Rufener (1964Rufener ( , 1985. The seven other sets, all in the Strömgren uvby system, were obtained in 1987, 1989 (b and c), 1990, 1992, 1993 and 1994 with the 50 cm Strömgren Automatic Telescope (SAT) and sixchannel photometer (Nielsen et al 1987).…”

Section: Photometrymentioning

confidence: 99%

The pre-main sequence spectroscopic binary AK Scorpii revisited

Alencar¹,

Melo²,

Dullemond³

et al. 2003

A&A

View full text Add to dashboard Cite

Abstract.We present an analysis of 32 high-resolution echelle spectra of the pre-main sequence spectroscopic binary AK Sco obtained during 1998 and 2000, as well as a total of 72 photoelectric radial-velocity observations from the period 1986-1994. These data allow considerable improvement of the period and other orbital parameters of AK Sco. Our analysis also includes eight series of photometric observations in the uvby and Geneva seven-color systems from 1987, 1989, 1990, 1992, 1994 and 1997. No eclipses or other periodic variations are seen in the photometry, but the well-determined HIPPARCOS parallax allows us to constrain the orbital inclination of the system to the range 65• , leading to the following physical parameters for the two near-identical stars: M = 1.35 ± 0.07 M , R = 1.59 ± 0.35 R , and v sin i = 18.5 ± 1.0 km s −1 . Disk models have been fit to the spectral energy distribution of AK Sco from 350 nm to 1100 µm. The above stellar parameters permit a consistent solution with an inner rim temperature of 1250 K, instead of the usual 1500 K corresponding to the dust evaporation temperature. Dynamical effects due to tidal interaction of the binary system are supposed to be responsible for pushing the inner disk radius outwards. Combining simultaneous photometric and spectroscopic data sets allows us to compute the dust obscuration in front of each star at several points over the orbit. The results demonstrate the existence of substructure at scales of just a single stellar diameter, and also that one side of the orbit is more heavily obscured than the other. The spectrum of AK Sco exhibits emission and absorption lines that show substantial variety and variability in shape. The accretion-related lines may show both outflow and infall signatures. The system displays variations at the binary orbital period in both the photospheric and accretion-related line intensities and equivalent widths, although with appreciable scatter. The periodic variations in the blue and red wing of Hβ are almost 180• out of phase. We find no evidence of enhanced accretion near the periastron passage in AK Sco as expected theoretically and observed previously in DQ Tau, a similarly young binary system with a mass ratio near unity and an eccentric orbit. The Hα equivalent width displays rather smooth variations at the stellar period, peaking around phases 0.6-0.7, far away from periastron where theory expects the maximum accretion rate to occur.

show abstract

“…162 measurements were obtained. The photometric reduction procedure was described by Rufener (1964Rufener ( , 1985; the photometric data in the Geneva system are collected in the General Catalogue (Rufener 1988) and its up-to-date database (Burki et al 2003). For a star of the brightness of HR 2501, the typical accuracy of the data is 0.005 in V (see, e.g.…”

Section: Observationsmentioning

confidence: 99%

Outbursts in the Be star HR 2501

Carrier

Burki

2003

A&A

View full text Add to dashboard Cite

Abstract. The Be star HR 2501 was monitored in photometry, from 1978 to 1998 in the G system and from 1990 to 1992 by the H satellite, and in spectroscopy from 1998 to 2001 by using the C spectrograph. Several mostly unrelated periods or time scales characterize the variability of HR 2501. First, the radial velocity data reveals that this is a new λ Eri star, with a period of 0.79187 d due to non-radial pulsations or clouds close to the stellar photosphere. Second, both G and H photometries exhibit a mid-to long-term variability of characteristic time ∼500 d and peak-to-peak amplitude ∼0.4 mag, most probably a consequence of the recurrent outbursts of matter from the rapidly rotating Be star towards its disk. Third, a characteristic time of ∼300 d between the outbursts is shown by spectroscopy by looking at the variations of the equivalent width of Hα, Hβ and HeI (5875.6 Å) emission lines (the outbursts studied in photometry and spectroscopy are unfortunately not the same due to the non-simultaneity of the monitorings). Fourth, the V/R ratio of the double peaks in Hα and Hβ show a periodic-type variation during the second of the spectroscopic outbursts, with periods of respectively 16.7 and 15.1 d, in agreement with the prediction of the dynamical evolution of a blob of material ejected from the equator of the star into the Keplerian disk. Fifth, a short-term photometric period of 0.46 d is detected during an epoch of intensive monitoring; however, it must be noted that if this variability is confirmed, the value of this short-term period is unsure. The other main results are: i) During the 27 months of the spectroscopic survey, in addition to the mentioned outbursts, the emission in Hα and Hβ lines decreased progressively until it almost completely vanishes at the end. ii) The estimated radius of the circumstellar disk varies and reaches 5.5, 4 and 2 stellar radii at maximum for the Hα, Hβ and HeI emission regions respectively; iii) The spectroscopic monitoring was particularly successful, and the series of observation of the line profiles, with the variation of the emission from day to day, is quite exceptional in the studies of Be stars.Key words. stars: emission-line, Be -stars: individual: HR 2501 -stars: variables: general -techniques: photometrictechniques: radial velocities -line: profiles IntroductionBe stars are variable early-type stars which, at least sometimes, exhibit emission lines in their spectra, produced by circumstellar envelopes (Struve 1931). Their variability, often present simultaneously in various aspects, are characterized by time scales between a few minutes and several years. The origin and connections of these variations remain an unsolved problem.One of the most remarkable changes in Be star spectra is the emission line profile variation, monitored through the V/R ratio, the relative intensity of the violet to red component of double emission linesSend offprint requests to: F. Carrier, e-mail: Fabien.Carrier@obs.unige.ch Based on observations collecte...

show abstract

Une étude épidémiologique de la bronchite chronique à Genève

Cited by 15 publications

References 27 publications

The CORALIE survey for southern extra-solar planets

The CORALIE survey for southern extra-solar planets

The pre-main sequence spectroscopic binary AK Scorpii revisited

Outbursts in the Be star HR 2501

Contact Info

Product

Resources

About