V3903 Sagittarii

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

position, motion, parallax:

position (J2000)	RA: 18h 9min 17.703sec	DEC: -23° 59' 18.39''	ą0.18 arcsec	source: 16
position (2000.74)	RA: 18h 9min 21sec	DEC: -23° 59' 17''	JD: 2451813.20
proper motion (J2000)	RA: 0.0001 arcsec/a	DEC: -0.005 arcsec/a		source: 16
galactic coord. (B1950)	longitude: 6.94°	latitude: -2.1°

magnitude:

visual	7 (observed)	source: 30
photovisual	7.9	source: 16

spectral information:

spectral class	B0		source: 96
Morgan-Keenan	B5/7(III)		source: 23
B-magnitude	7.47 ą0.011	B-V-magnitude	0.14
U-magnitude	6.67 ą0.013	U-B-magnitude	-0.8

variability information:

source of data: 30

variability type	271
var. amplitude	0.45

sources:

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 6min 14.284sec	DEC: -23° 59' 51.95''	ą0.049 arcsec
position (2000.74)	RA: 18h 9min 20sec	DEC: -23° 59' 17''	JD: 2451813.20
position (J2000)	RA: 18h 9min 17.927sec	DEC: -23° 59' 17.6''
proper motion B1950 (FK4)	RA: 0.0028 arcsec/a	DEC: 0.007 arcsec/a	ą0.01 arcsec/a in RA ą0.007 arcsec/a in DEC
proper motion J2000 (FK5)	RA: 0.0028 arcsec/a	DEC: 0.008 arcsec/a
source of proper motion data	Determined by source catalog

magnitude:

visual	7.5 (accuracy: 2 decimals)
source of visual magnitude data	Taken from Harvard or San Luis photometry.

spectral information:

spectral class	B0
source of spectral data	Taken from the Henry Draper Catalogue or no spectrum in source catalog.

catalogues

source catalogue	GC, catalogue number: 24732
Durchmusterung	CD-2413962
Boss General Catalogue	24732
Henry Draper Catalogue	165921

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

position:

position (equinox 1950.0)

RA: 18h 6min 14.3sec

DEC: -23° 59' 52''

variability informations:

variability type	INA:	eruptive variable star
magnitute at max. brightness	7
magnitute at min. brightness	7.45
photometric system	visual, photovisual or Johnson's V

spectral information

spectral class

O8Vn

references

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

miscanellous

ID in the GCVS catalogue	72/3903
constellation	Sagittarius
notes on existence	The star is equivalent to '0723904 V3904'.
There are notes in published catalog.

variability type description

variability type

description

INA

Orion variables. Irregular, eruptive variables connected with bright or dark diffuse nebulae or observed in the regions of these nebulae. Some of them may show cyclic light variations caused by axial rotation. In the Spectrum-Luminosity diagram, they are found in the area of the main sequence and subgiants. They are probably young objects that, during the course of further evolution, will become light-constant stars on the zero-age main
sequence (ZAMS). The range of brightness variations may reach several magnitudes. In the case of rapid light variations having been observed (up to 1 mag in 1-10 days), the letter "S" is added to the symbol for the type (INS).
This type may be divided into the following subtypes: INA, INB, INT, IN(YY).

INA
Orion variables of early spectral types (B-A or Ae). They are often characterized by occasional abrupt Algol-like fadings (T Ori);

INB
Orion variables of intermediate and late spectral types, F-M or Fe-Me (BH Cep, AH Ori). F-type stars may show Algol-like fadings similar to those of many INA stars; K-M stars may produce flares along with irregular light variations;

INT
Orion variables of the T Tauri type. Stars are assigned to this type on the basis of the following (purely spectroscopic) criteria: spectral types are in the range Fe-Me. The spectra of most typical stars resemble the spectrum of the solar chromosphere. The feature specific to the type is the presence of
the flourescent emission lines Fe II 4046, 4132 A (anomalously intense in the spectra of these stars), emission lines [Si II] and [O I], as well as the absorption line Li I 6707 A. These variables are usually observed only in diffuse nebulae. If it is not apparent that the star is associated with a nebula, the letter "N" in the symbol for the type may be omitted, e.g., IT (RW AUR);

IN(YY)
Some Orion variables (YY Ori) show the presence of absorption components on the redward sides of emission lines, indicating the infall of matter toward the stars' surfaces. In such cases, the symbol for the type may be accompanied by the symbol "YY".