Contents
Images
Upload your image
DSS Images Other Images
Related articles
Pulkovo compilation of radial velocities for 35495 stars in a common system.
Not Available
| Effective temperature scale and bolometric corrections from 2MASS photometry
We present a method to determine effective temperatures, angularsemi-diameters and bolometric corrections for population I and II FGKtype stars based on V and 2MASS IR photometry. Accurate calibration isaccomplished by using a sample of solar analogues, whose averagetemperature is assumed to be equal to the solar effective temperature of5777 K. By taking into account all possible sources of error we estimateassociated uncertainties to better than 1% in effective temperature andin the range 1.0-2.5% in angular semi-diameter for unreddened stars.Comparison of our new temperatures with other determinations extractedfrom the literature indicates, in general, remarkably good agreement.These results suggest that the effective temperaure scale of FGK starsis currently established with an accuracy better than 0.5%-1%. Theapplication of the method to a sample of 10 999 dwarfs in the Hipparcoscatalogue allows us to define temperature and bolometric correction (Kband) calibrations as a function of (V-K), [m/H] and log g. Bolometriccorrections in the V and K bands as a function of T_eff, [m/H] and log gare also given. We provide effective temperatures, angularsemi-diameters, radii and bolometric corrections in the V and K bandsfor the 10 999 FGK stars in our sample with the correspondinguncertainties.
| Photometry of symbiotic stars. XI. EG And, Z And, BF Cyg, CH Cyg, CI Cyg, V1329 Cyg, TX CVn, AG Dra, RW Hya, AR Pav, AG Peg, AX Per, QW Sge, IV Vir and the LMXB V934 Her
We present new photometric observations of EG And, Z And, BF Cyg, CHCyg, CI Cyg, V1329 Cyg, TX CVn, AG Dra, RW Hya, AG Peg, AX Per, IV Virand the peculiar M giant V934 Her, which were made in the standardJohnson UBV(R) system. QW Sge was measured in the Kron-Cousin B, V,RC, IC system and for AR Pav we present its newvisual estimates. The current issue gathers observations of theseobjects to December 2003. The main results can be summarized as follows:EG And: The primary minimum in the U light curve (LC) occurred at theend of 2002. A 0.2 -- 0.3 mag brightening in U was detected in theautumn of 2003. Z And: At around August 2002 we detected for the firsttime a minimum, which is due to eclipse of the active object by the redgiant. Measurements from 2003.3 are close to those of a quiescent phase.BF Cyg: In February 2003 a short-term flare developed in the LC. Adifference in the depth of recent minima was detected. CH Cyg: This starwas in a quiescent phase at a rather bright state. A shallow minimumoccurred at JD 2 452 730, close to the position of the inferiorconjunction of the giant in the inner binary of the triple-star model ofCH Cyg. CI Cyg: Our observations cover the descending branch of a broadminimum. TX CVn: At/around the beginning of 2003 the star entered abright stage containing a minimum at JD 2 452 660. AG Dra: Newobservations revealed two eruptions, which peaked in October 2002 and2003 at 9.3 in U. AR Pav: Our new visual estimates showed atransient disappearance of a wave-like modulation in the star'sbrightness between the minima at epochs E = 66 and E = 68 and itsreappearance. AG Peg: Our measurements from the end of 2001 showedrather complex profile of the LC. RW Hya: Observations follow behaviourof the wave-like variability of quiet symbiotics. AX Per: In May 2003 a0.5 mag flare was detected following a rapid decrease of the light to aminimum. QW Sge: CCD observations in B, V, RC, ICbands cover a period from 1994.5 to 2003.5. An increase in the star'sbrightness by about 1 mag was observed in all passbands in 1997. Lesspronounced brightening was detected in 1999/2000. V934 Her: Ourobservations did not show any larger variation in the optical as areaction to its X-ray activity.
| Photometry of symbiotic stars. X. EG And, Z And, BF Cyg, CH Cyg, V1329 Cyg, AG Dra, RW Hya, AX Per and IV Vir
We present new photometric observations of EG And, Z And, BF Cyg, CHCyg, V1329 Cyg, AG Dra, RW Hya, AX Per and IV Vir made in the standardJohnson UBVR system. The current issue summarizes observations of theseobjects to 2001 December. The main results can be summarized as follows:EG And: A periodic double-wave variation in all bands as a function ofthe orbital phase was confirmed. A maximum of the light changes wasobserved in U (Delta U ~ 0.5 mag). Z And: Our observations cover anactive phase, which peaked around 8.4 in U at the beginning of 2000December. Consequently, a gradual decrease in the star's brightness hasbeen observed. BF Cyg: A periodic wave-like variation in the opticalcontinuum reflects a quiescent phase of this star. A complex light curve(LC) profile was observed. CH Cyg: The recent episode of activity endedin Spring 2000. We determined the position of an eclipse in the outerbinary at JD 2451426 +/- 3. Recent observations indicate a slow increasein the star's brightness. V1329 Cyg: Observations were made around amaximum at 2001.2. AG Dra: Our measurements from the Autumn of 2001revealed a new eruption, which peaked at ~JD 2452217. RW Hya: The lightminimum in our mean visual LC precedes the time of the spectroscopicconjunction of the giant in the binary. AX Per: A periodic wave-likevariation was observed. Our recent observations revealed a secondaryminimum at the orbital phase 0.5, seen best in the V and B bands. IVVir: The LC displays a double-wave throughout the orbital cycle.
| UBV Photometry of the Symbiotic Star Z And During its 2000 Outburst
We present new photometric U, B, V observations of classical symbioticstar Z And. Our new observations cover an active phase, which began atthe end of 2000 August. The star's brightness reached its maximum ofabout 8.4 mag in U at the end of 2000 November. This value exceeded thatobserved during the last major outburst in 1984-85.
| Photometry of symbiotic stars. IX. TX CVn, CH Cyg, AX Per and AR Pav
We present new photometric observations of TX CVn, CH Cyg, AX Per and ARPav. The main results can be summarized as follows: TX CVn: Thehistorical 1893-2000 photographic/B-band light curve (LC) is presentedfor the first time. From 1892 to ~1920, the star was quiet, but thenentered a series of outbursts peaking in 1920, 1945, 1952 and 1962. From~1988 till the present time, TX Cvn has gradually declined. CH Cyg: Ourobservations cover an active phase, which began in May 1998. At thebeginning of June 1999 the star's brightness in the U band rapidlydecreased due to an eclipse of the active inner binary (the symbioticpair) by a cool giant in the outer orbit. AX Per: The historical1887-2000 photographic/B-band LC is summarized here for the first time.It is characterized by long-lasting periods of quiescence with thesuperposition of a few bright stages lasting about 1.5 orbital cycles.Our photoelectric U,B,V observations revealed a drastic change in the LCprofile, which occurred after JD 2 450 000 (1995.8). A small 0.6 magflare at that time and consequently very broad wave-like variation inthe LC developed. This event was caused by the dilution of a shellaround the hot star. AR Pav: Our observations show that the recentactive phase, which began in 1985.7 is over. During the activity, AR Pavdeveloped a complex wave-like variation at the level of ~1.5 mag in thevisual band. The transition to a quiet phase was rapid -- the wave-likevariation disappeared.
| Photometric study of the eclipsing binary EG CEP
New photoelectric B and V observations of EG Cep were taken and 11 newminima times were determined. They confirm the long-term increase of theorbital period. The light-curve analysis shows that the system issemi-detached. Mass transfer from the less to the more massive componentis responsible for the observed orbital period increase. Variations inthe transferred matter projected onto the surface of the components areresponsible for the colour dependent variable shift of the minima. Thiseffect, more pronounced in the secondary minima, explains also thedisagreement of the limb-darkening coefficient of the secondarycomponent with the theoretical value.
| Kinematics and properties of F stars near the North Galactic Pole. II - The isothermal disc
Radial velocities are given for about 550 photometrically-identifieddisk-population F stars lying within 15 deg of the North Galactic Pole.The overall radial and z-velocity distributions are found to be closelyGaussian, with corrected rms and mean z velocities of 11.3 + or - 0.6and -9.5 + or - 0.5 km/s, respectively. The isothermal kinematics of thepopulation are reflected in the constant velocity dispersion to a zdistance of 400 pc. No systematic variation of either the velocitydispersion or the stellar age with the metallicity-sensitive Stromgrendelta m1 index is noted over a range of ages up to 5 Gyr.
| Further Studies of A-Stars and F-Stars in the Region of the North Galactic Pole - Part Four - a Catalogue of Uvbyr Photometry and Derived Quantities
Not Available
| Further Studies of A-Stars and F-Stars in the Region of the North Galactic Pole - Part Three - a Catalogue of Star Names and Positions
Not Available
| Studies of A and F stars in the region of the North galactic pole-II. uvby β photometry
Not Available
| Studies of A and F stars in the region of the North galactic pole-I. Radial velocities and MK Classifications
Not Available
| Investigations on the stars in high galactic latitudes. III. Spectrophotometric analysis of about 3000 stars down to the photographic magnitude 13.5.
Not Available
|
Submit a new article
Related links
Submit a new link
Member of following groups:
|
Observation and Astrometry data
| Constellation: | りょうけん座 |
| Right ascension: | 12h46m39.59s |
| Declination: | +36°50'54.5" |
| Apparent magnitude: | 9.186 |
| Proper motion RA: | -26.2 |
| Proper motion Dec: | -5.1 |
| B-T magnitude: | 9.56 |
| V-T magnitude: | 9.217 |
Catalogs and designations:
|
