catalogues and names

Smithsonian Astrophysical Observatory Star Catalog

Combined General Catalogue of Variable Stars (Vol. I-III)

catalogues and names

catalogues and names

AR Sgr, SAO 187547, CD -23 14922

data from Smithsonian Astrophysical Observatory Star Catalog (SAO Staff 1966; USNO, ADC 1990)

position and proper motion:

position (B1950)	RA: 18h 56min 39.868sec	DEC: -23° 46' 37.44''	±0.029 arcsec
position (2000.72)	RA: 18h 59min 45sec	DEC: -23° 42' 22''	JD: 2451809.28
position (J2000)	RA: 18h 59min 42.168sec	DEC: -23° 42' 25.32''
proper motion B1950 (FK4)	RA: 0.0014 arcsec/a	DEC: 0.008 arcsec/a	±0.015 arcsec/a in RA ±0.015 arcsec/a in DEC
proper motion J2000 (FK5)	RA: 0.0014 arcsec/a	DEC: 0.008 arcsec/a
source of proper motion data	Determined by source catalog

magnitude:

visual	9.3 (accuracy: 1 decimal)
source of visual magnitude data	Taken from Cordoba Zones (Resultados)

spectral information:

spectral class	G4
source of spectral data	Classified by M. W. Mayall.

catalogues

source catalogue	Yale Transactions 14, catalogue number: 13197
Durchmusterung	CD-2314922

data from Combined General Catalogue of Variable Stars (Vol. I-III) (Kholopov+ 1998)

position:

position (equinox 1950.0)

RA: 18h 56min 39.9sec

DEC: -23° 46' 37''

variability informations:

variability type	RVA	pulsating variable star
magnitute at max. brightness	9.1
magnitute at min. brightness	13.5
photometric system	photographic magnitudes
epoch for maximum light [JD]	2421113 6. September 1916, 12:00:00 UT
period [d]	87.87
next maximum light [JD]	2451867.5 19. November 2000, 00:00:00 UT

spectral information

spectral class

F5e-G6

references

to a study	Vol. I GCVS (see Kholopov et al. 1985-1988)
to a chart/photograph	Vol. II GCVS

miscanellous

ID in the GCVS catalogue	72/71
constellation	Sagittarius
notes on existence	The star is equivalent to '0720072 AS'.
There are notes in published catalog.

variability type description

variability type

description

RVA

Variables of the RV Tauri type. These are radially pulsating supergiants having spectral types F-G at maximum light and K-M at minimum. The light curves are characterized by the presence of double waves with alternating primary and secondary minima that can vary in depth so that primary minima may become secondary and vice versa. The complete light amplitude may reach 3-4 mag in V. Periods between two adjacent primary minima (usually called formal periods) lie in the range 30-150 days (these are the periods appearing in the Catalogue). Two subtypes, RVA and RVB, are recognized: RVA RV Tauri variables that do not vary in mean magnitude (AC Her); RVB RV Tauri variables that periodically (with periods from 600 to 1500 days and amplitudes up to 2 mag in V) vary in mean magnitude (DF Cyg, RV Tau).