Search Publications
Hunting for Long-lived Protoplanetary Disks Observed with AKARI/FIS
Liu, Yao; Liu, Qiong
Twenty-one YSO (Young Stellar Object) candidates nearby the solar system have been identified through cross-correlating Hipparcos (High Precision Parallax Collecting Satellite) catalog with the AKARI/FIS YSO catalog, and the reliability is over 90%. The central objects cover the spectral types from B to M. The Hipparcos's accurate measurements of …
A Kinematical Study of the Galaxy Based on the Revised Hipparcos Astrometric Data
Shen, Ming; Zhang, Hong
On the basis of the revised Hipparcos data recently released, the zero-point of the period-luminosity relation for classical cepheids is reexamined. Fitting the proper motion and radial velocity data via an axisymmetric model, the Oort constants and circular rotation velocity of the LSR are calculated to obtain the Galactocentric distance of the S…
A Study of the Scale Height of the Thin Galactic Disk in the Solar Neighborhood
Zhu, Zi; Kong, Da-Li
An attempt is made to determine the scale height of the thin Galactic disk in the solar neighborhood using various stellar samples from the accurate astrometric data of the Hipparcos satellite. Using the Tycho color indices and considering the completeness of the samples, several samples were selected from the main sequence and the horizontal bran…
A Method to Improve Binary Orbits by Incorporating Long-term Observational Data
Ren, Shu-lin; Fu, Yan-ning
Early ground-based observations have accumulated a large volume of data on binary stellar systems. Compared to the more recent data obtained by various new techniques, these older data have both the disadvantage of low precision and the advantage of long time-span. For long-period binary systems having available both long-term data and Hipparcos d…
Precession Constant Correction and Proper Motion Systems of FK5 and Hipparcos
Zhu, Zi
Results of many researches have shown that the relation between the proper motion systems of FK5 and Hipparcos is not consistent with the precession constant corrections determined by VLBI and LLR. We analysed proper motion data of PPM and ACRS based on the FK5 system for many different sub-samples and found that consistent values of the precessio…
Near-infrared photometry of 20 hipparcos carbon stars
Chen, Pei-Sheng; Yang, Xiao-Hong; Wang, Xun-Hao
Near-infrared JHK photometry was carried out for 20 carbon stars observed by the satellite Hipparcos. From the observations, bolometric corrections in the K band ( BCK), apparent bolometric magnitudes ( mrmbo) and effective temperatures ( Te) of these stars were estimated. Combined with the trigonometric parallaxes…
The proper and space motions of the globular cluster NGC 4147 on the Hipparcos system
Wang, Jia-ji; Wu, Zhen-yu
Dr M. Geffert, of Sternwarte der Universität Bonn, kindly provided us with the positions and proper motions of 82 stars in the field of the globular cluster NGC 4147, reduced with 11 reference stars from the Hipparcos catalogue. We used 54 of these stars to re-reduce the observations by Wang Jia-ji and Gupta [1]. Based on the new proper…
Proper motions of Hipparcos stars in two plate areas
Wang, Shu-he; Tang, Zheng-hong; Jin, Wen-jing
Using the ACT reference catalogue as preliminary reference we have reduced 31 exposures on 15 plates in two areas taken with the 40-cm refractor of our Observatory. Using the central overlapping technique and an iterative procedure we have derived high-precision positions and proper motions for 54 stars, including 16 Hipparcos stars. For the latte…
A kinematic study of the Galaxy
Liu, Yu; Ma, Wen-zhang
Using the proper motion and parallax data for 1011 O-B stars in the Hipparcos Catalogue we have derived the Oort constants, A = 17.60 ± 0.21 (km/s)/kpc, B = -14.62 ± 0.20 (km/s)/kpc, and a solar velocity V⊙ = 16.7 ± 0.10 km/s in the direction l⊙ = 45.3° ± 2.8°, b⊙ = 21.0° ± 2.3°. For a galactocentric distance of th…
Galactic kinematics derived from classical cepheids
Zhu, Zi
On the basis of radial velocity and Hipparcos proper motion data, we have analyzed the galactic kinematics of classical Cepheids. Using the 3-D Ogorodnikov-Milne model we have determined the rotational velocity of the Galaxy to be V0 = 240.5 ± 10.2 km/s, on assuming a glactocentric distance of the Sun of R0 = 8.5 kpc. The res…