V0987 Tauri

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

position, motion, parallax:

position (J2000)	RA: 4h 21min 58.838sec	DEC: +28° 18' 6.14''	ą0.42 arcsec	source: 16
position (2000.74)	RA: 4h 22min 2sec	DEC: +28° 18' 12''	JD: 2451813.20
proper motion (J2000)	RA: 0.0005 arcsec/a	DEC: -0.033 arcsec/a		source: 16
galactic coord. (B1950)	longitude: 169.37°	latitude: -15.03°

magnitude:

visual	9.1 (derived)
photographic	9.8	source: 35

spectral information:

spectral class	G0		source: 96
Morgan-Keenan	G2III		source: 98

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
35	HD Extension Charts
Nesterev, V.V., Kuzmin, A.V., Ashimbaeva, N.T., Volchkov, A.A., Roser, S., Bastian, U., 1995 A&AS, 110, 367. "The Henry Draper Extension Charts: A catalogue of accurate positions, proper motions, magnitudes and spectral types of 86933 stars"
96	SAO or HD/HDE Catalog
Reference from Value 1 or Reference from Value 2
98	SKYMAP Master Catalog Version 3.7
Reference from Value 97 [original data sources Catalog Version 3.7 are identified in SKYMAP Version 3.7]

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

position and proper motion:

position (B1950)	RA: 4h 18min 52.517sec	DEC: +28° 11' 6.59''	ą0.032 arcsec
position (2000.74)	RA: 4h 22min 2sec	DEC: +28° 18' 15''	JD: 2451813.20
position (J2000)	RA: 4h 21min 58.866sec	DEC: +28° 18' 7.92''
proper motion B1950 (FK4)	RA: 0.0011 arcsec/a	DEC: -0.007 arcsec/a	ą0.015 arcsec/a in RA ą0.011 arcsec/a in DEC
proper motion J2000 (FK5)	RA: 0.001 arcsec/a	DEC: -0.009 arcsec/a
source of proper motion data	Determined by source catalog

magnitude:

visual	8.8 (accuracy: 1 decimal)
source of visual magnitude data	Taken from AGK1.
photographic	9.7 (accuracy: 2 decimals)
source of photographic magnitude data	Determined by source catalog.

spectral information:

spectral class	G0
source of spectral data	Taken from the HD with M stars reclassified by Miss Cannon.

catalogues

source catalogue	Yale Transactions 24, catalogue number: 2056
Durchmusterung	BD+27 657
Henry Draper Catalogue	283572

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

position:

position (equinox 1950.0)

RA: 4h 18min 52.5sec

DEC: +28° 11' 7''

variability informations:

variability type	INT	eruptive variable star
magnitute at max. brightness	8.98
magnitute at min. brightness	9.1
photometric system	visual, photovisual or Johnson's V

references

to a study	F.M.Walter, A.Brown, J.L.Linsky, A.E.Rydgren, F.Vrba, M.Roth, L.Carrasco, P.F.Chugainov, N.I.Shakovskaya, C.L.Imhoff, ApJ 314, No.1,297,1987.
to a chart/photograph	no chart is avaible, but the star is contained in the 'Bonner Durchmusterung'

miscanellous

ID in the GCVS catalogue	78/987
constellation	Taurus
notes on existence	The star is equivalent to '69078'.

variability type description

variability type

description

INT

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".