XX Sagittarii

data from SKY2000 - Master Star Catalog (Myers+ 1997)

position, motion, parallax:

position (J2000)	RA: 18h 24min 44.517sec	DEC: -16° 47' 49.73''	ą0.18 arcsec	source: 16
position (2000.72)	RA: 18h 24min 47sec	DEC: -16° 47' 48''	JD: 2451806.31
proper motion (J2000)	RA: 0.0002 arcsec/a	DEC: 0.004 arcsec/a		source: 16
radial velocity	2.5 km/s			source: 11
galactic coord. (B1950)	longitude: 14.99°	latitude: -1.88°

magnitude:

visual	8.41 (observed)	source: 30
photovisual	9.2	source: 16

spectral information:

spectral class	G5		source: 96
Morgan-Keenan	F7/8II		source: 23
B-magnitude	9.34 ą0.02	B-V-magnitude	0.93

variability information:

source of data: 30

variability type	113
var. amplitude	0.87
var. period	6.42
var. epoch	2435308 19. July 1955, 12:00:00 UT
next max light	2451807.4 19. September 2000, 21:36:00 UT

sources:

11	General Catalogue of Stellar Radial Velocities
Wilson, R.E., General Catalogue of Stellar of Stellar Radial Radial Velocities, Washington, DC: Carnegie Institute of Washington, 1953
16	PPM North and PPM South Catalogs and PPM Supplement
Roser, S., and U. Bastian, "Catalogue of Positions and Proper Motions," A&AS, Vol. 74, p. 449, 1988, and Bastian, U., et al., "Catalogue of Positions and Proper Motions - South," 1993
23	Michigan Catalog of 2-Dimensional Spectral Types, Volume IV
Houk, N. and Smith-Moore, D., Michigan Catalogue of 2-Dimensional Spectral Types for the HD Stars, Vol. 4, (Zones -25 to -12 Degrees), Ann Arbor: The University of Michigan, 1988
30	GCVS, 4th edition
Kholopov, P.N., et al., General Catalogue of Variable Stars, fourth edition, Moscow: Nauka Publishing House, 1985-88
96	SAO or HD/HDE Catalog
Reference from Value 1 or Reference from Value 2

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

position and proper motion:

position (B1950)	RA: 18h 21min 50.642sec	DEC: -16° 49' 31.59''	ą0.034 arcsec
position (2000.72)	RA: 18h 24min 47sec	DEC: -16° 47' 49''	JD: 2451806.31
position (J2000)	RA: 18h 24min 44.526sec	DEC: -16° 47' 49.91''
proper motion B1950 (FK4)	RA: 0.0001 arcsec/a	DEC: -0.002 arcsec/a	ą0.021 arcsec/a in RA ą0.015 arcsec/a in DEC
proper motion J2000 (FK5)	RA: 0.0003 arcsec/a	DEC: -0.001 arcsec/a
source of proper motion data	Determined by source catalog

magnitude:

visual	9 (accuracy: 1 decimal)
source of visual magnitude data	Taken from AGK1.

spectral information:

spectral class	G5
source of spectral data	Taken from the HD with M stars reclassified by Miss Cannon.

catalogues

source catalogue	Yale Transactions 12 Part I, catalogue number: 6735
Durchmusterung	BD-16 4859
Henry Draper Catalogue	169315

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

position:

position (equinox 1950.0)

RA: 18h 21min 50.6sec

DEC: -16° 49' 32''

variability informations:

variability type	CEP	pulsating variable star
magnitute at max. brightness	8.41
magnitute at min. brightness	9.28
photometric system	visual, photovisual or Johnson's V
epoch for maximum light [JD]	2435308.449 19. July 1955, 22:46:34 UT
period [d]	6.42414
next maximum light [JD]	2451812.06466 24. September 2000, 13:33:07 UT
rising time	30 % of period

spectral information

spectral class

F6-G2

references

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

miscanellous

ID in the GCVS catalogue	72/49
constellation	Sagittarius
notes on existence	The star is equivalent to '0720050 XY'.
There are notes in published catalog.

variability type description

variability type

description

CEP

Cepheids. Radially pulsating, high luminosity (classes Ib-II) variables with periods in the range of 1-135 days and amplitudes from several hundredths to 2 mag in V (in the B band, the amplitudes are greater). Spectral type at maximum light is F; at minimum, the types are G-K. The longer the period of light variation,the later is the spectral type. The maximum of the surface-layer expansion velocity almost coinciding with maximum light.