l Tauri

The object was found in the following catalogues:
  1. The Bright Star Catalogue, 5th Revised Ed. (Preliminary Version)

  2. SKY2000 - Master Star Catalog

  3. Smithsonian Astrophysical Observatory Star Catalog

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

catalogues and names l Tau, lam Tau, 35 Tau, HR 1239, HD 25204, SAO 93719, FK5: 150
constellation Taurus

data from The Bright Star Catalogue, 5th Revised Ed. (Preliminary Version) (Hoffleit+, 1991)

object is infrared source (Engels et al., 1982)

position, motion, parallax:

position (J2000) RA: 4h 0min 40,8sec DEC: +12 29' 25''
position (J1900) RA: 3h 55min 8,3sec DEC: +12 12' 28''
proper motion (J2000) RA: -0,006 arcsec/a DEC: -0,012 arcsec/a
radial velocity 18 km/s
note: spectroscopic binaries, double lined spectra
note: orbital data avaible
rotational velocity 87 km/s (uncertain) (variable)
trigonometric parallax 0,002 arcsec
note (category: dynamical parallaxes): 0.0042".


visual magnitude 3,47
(V on UBV Johnson system)

spectral / color information

spectral class B3V+A4IV
B-V-magnitude -0,12
U-B-magnitude -0,62
R-I-magnitude -0,09

variability information

variable star identification Lam Tau
note (category: variability): EA 3.3 - 3.80p, B3V+A, 3.952955d, i 86d.

double/multiple star system information

note (category: spectroscopic binaries): 3.9540d, K 55.4k/s, V0 +15.2k/s, asini 2.99. RV also varies in 33.025d, triple system. Masses 6.8, 1.8 and about 1 solar.

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

position, motion, parallax:

position (J2000) RA: 4h 0min 40,819sec DEC: +12 29' 25,24'' 0,06 arcsec source: 15
proper motion (J2000) RA: -0,0004 arcsec/a DEC: -0,012 arcsec/a source: 25
radial velocity 18 km/s source: 25
trigonometric parallax 0,002 - source: 25
galactic coord. (B1950) longitude: 178,38 latitude: -29,38
GCI unit vector (J2000) X: 0,485654 Y: 0,846974 Z: 0,216275


visual 3,4 (observed) source: 31

spectral information:

spectral class B3 source: 96
Morgan-Keenan B3V+A4IV source: 25
B-magnitude 3,35 0,05 B-V-magnitude -0,12
U-magnitude 2,73 0,05 U-B-magnitude -0,62

variability information:

source of data: 30
variability type 10
var. amplitude 0,54
var. period 3,95
var. epoch 2421507
5. October 1917, 12:00:00 UT
next max light 2451625,75
22. March 2000, 06:00:00 UT


15 FK5, FK5 Extension and FK5 Supplement
Fricke, W., H. Schwan and T. Lederle, "Fifth Fundamental Catalogue (FK5), Part I. The Basic Fundamental Stars," Veroff. Astronomisches Recheninstitut, No. 32, Heidelberg, Germany, 1988, and Fricke, W., H. Schwan, and T.E. Corbin, "Fifth Fundamental Catalogue (FK5), Part II. The FK5 Extension," Veröff. Astronomisches Recheninstitut, No. 33, Heidelberg, Germany, 1991
25 Bright Star Catalogue, 5th edition
Hoffleit, D. and Warren, W.H. Jr., The Bright Star Catalogue, 5th Revised Edition, Version 2, 1994
30 GCVS, 4th edition
Kholopov, P.N., et al., General Catalogue of Variable Stars, fourth edition, Moscow: Nauka Publishing House, 1985-88
31 CRM' (non-GCVS variable data)
Warren, W.H. Jr., Northern Hemisphere Catalog of Red Magnitudes, 1994
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 (J1950) RA: 3h 57min 54,378sec DEC: +12 21' 2,13'' 0,004 arcsec
position (J2000) RA: 4h 0min 40,822sec DEC: +12 29' 25,33''
proper motion J1950 (FK4) RA: -0,0005 arcsec/a DEC: -0,009 arcsec/a 0,001 arcsec/a in RA
0,001 arcsec/a in DEC
proper motion J2000 (FK5) RA: -0,0004 arcsec/a DEC: -0,011 arcsec/a
source of proper motion data Determined by source catalog


visual 4 (accuracy: 2 decimals)
source of visual magnitude data Arithmetic mean of maximum and minimum magnitudes of a variable star

spectral information:

spectral class B3
source of spectral data Taken from the Henry Draper Catalogue or no spectrum in source catalog.

remarks for duplicity and variability

Variable star in visual magnitude in source catalog


source catalogue FK4, catalogue number: 150
Durchmusterung BD+12 539
Boss General Catalogue 4805
Henry Draper Catalogue 25204

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


position (J1950) RA: 3h 57min 54,4sec DEC: +12 21' 2''

variability informations:

variability type EA/DM close binary eclipsing system
magnitute at max. brightness 3,37
magnitute at min. brightness 3,91
photometric system visual, photovisual or Johnson's V
epoch for maximum light [JD] 2421506,8506
5. October 1917, 08:24:52 UT
period [d] 3,9529478
next maximum light [JD] 2451624,3598882
20. March 2000, 20:38:14 UT
duration of the eclipse 15 % of period
the duration of the light constancy phase at minimum light is equal to zero

spectral information

spectral class B3V+A4IV


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


ID in the GCVS catalogue 78/9011
constellation Taurus
notes on existence The star is equivalent to '0789017 rho'.
There are notes in published catalog.

variability type description

variability type description
EA Eclipsing binary systems. These are binary systems with orbital planes so close to the observer's line of sight (the inclination i of the orbital plane to the plane orthogonal to the line of sight is close to 90 deg) that the components periodically eclipse each other.
Consequently, the observer finds changes of the apparent combined brightness of the system with the period coincident with that of the components' orbital motion.

Algol (Beta Persei)-type eclipsing systems. Binaries with spherical or slightly ellipsoidal components. It is possible to specify, for their light curves, the moments of the beginning and end of the eclipses. Between eclipses the light remains almost constant or varies insignificantly because of reflection effects, slight ellipsoidality of components, or physical variations. Secondary minima may be absent. An extremely wide range of periods is observed, from 0.2 to >= 10000 days. Light amplitudes are also quite different and may reach several magnitudes.

Beta Lyrae-type eclipsing systems. These are eclipsing systems having ellipsoidal components and light curves for which it is impossible to specify the exact times of onset and end of eclipses because of a continuous change of a system's apparent combined brightness between eclipses; secondary minimum is observed in all cases, its depth usually being considerably smaller than that of the primary minimum; periods are mainly longer than 1 day. The components
generally belong to early spectral types (B-A). Light amplitudes are usually <2 mag in V.

W Ursae Majoris-type eclipsing variables. These are eclipsers with periods shorter than 1 days, consisting of ellipsoidal components almost in contact and having light curves for which it is impossible to specify the exact times of onset and end of eclipses. The depths of the primary and secondary minima are almost equal or differ insignificantly. Light amplitudes are usually <0.8 mag in V. The components generally belong to spectral types F-G and later.
DM Detached main-sequence systems. Both components are main-sequence stars and do not fill their inner Roche lobes.