Tau Bootes

Summary

Visual magnitude: 4.49
Distance: 49.6 +/- 1.5 light years
Luminosity: 2.99 +/- 0.19 x Sun's luminosity

Position information for 01 ene 2000 0:00:00
(Julian day number 2451544.41667)

Apparent RA (epoch of date):	13h 47m 14.39s
Apparent Dec (epoch of date):	+17° 27' 25.1"
Constellation: Bootes

Altitude:	-21° 32' 7"
Azimuth:	40° 33' 44"

Rise:		2h 16m 50s
Transit:		9h 21m 3s
Set:		16h 25m 17s

Names and Catalog Numbers

Bayer letter:		? Bootis
Flamsteed number:	4 Bootis
Tycho catalog number:	TYC 1460-132-1
PPM number:		PPM 130070
Henry Draper number:	HD 120136
DM number:		BD +18 2782 

Star Atlas Chart Numbers

Herald-Bobroff Astroatlas, Chart C-47
Millennium Star Atlas, Charts 697-698 (Vol II)
Sky Atlas 2000.0, Chart 14
Uranometria 2000 Chart 151, Vol 1

Tycho Catalog Data

Tycho Catalogue (ESA SP-1200, 1997).

Tycho Identifier/Proximity Flag

Catalog number: TYC 1460-132-1

Proximity flag: None

Descriptor

V magnitude: 4.49
Source of V magnitude: Johnson UBV photometric system.

Astrometric Data

Equatorial coordinates (epoch J2000.0, ICRS)

RA:	13h 47m 15.7457s
Dec:	+17° 27' 24.848"

Standard errors of the equatorial coordinates (epoch J1991.25)

RA:	0.0018 arcsec
Dec:	0.0015 arcsec

Astrometric reference flag: This is a dubious astrometric reference star in the context of the Tycho catalog.

Trigonometric parallax: 0.06580 arcsec
Standard error of the parallax: 0.00210 arcsec

Proper motion components (epoch J1991.25, ICRS)

RA:	-0.49898 arcsec/yr
Dec:	+0.05270 arcsec/yr

Standard errors of the proper motion components

RA:	0.0020 arcsec
Dec:	0.0015 arcsec

Number of accepted data points: 158
Goodness-of-fit parameter, F2: 2.32

Hipparcos catalog number: 67275

Astrometric quality flag: 1 (very high).
Signal-to-noise ratio of the star image, Fs: 13.0

Source of astrometric data: Standard data processing.

Photometric Data

Mean Bt magnitude: 5.075
Standard error: 0.002

Mean Vt magnitude: 4.541
Standard error: 0.002

Source of photometric data: The Bt,Vt data are median values, rather than de-censored mean values (mainly relevant for bright stars with Bt<=8.5 mag and Vt<=8.0 mag).

Johnson B-V colour index: 0.498
Standard error: 0.002

Number of transits used in mean photometry: 143
Vt scatter, s: 0.019 mag
Vt magnitude at maximum luminosity: 4.52
Vt magnitude at minimum luminosity: 4.56

Previously known or suspected variability: The star is listed in the "New Catalog of Suspected Variable Stars" (P.N.Kholopov et al., Publ. Office 'Nauka', Moscow, 1982).

Variability of the Tycho measurements: Apparent variability in the Tycho data; this may be due to duplicity, and this flag is only set if an indication of duplicity was also found.

Unresolved duplicity status: Weak indication of duplicity, combined with indication of variability.

Cross-identification and Notes

PPM identifier: PPM 130070
HD identifier: HD 120136
DM identifier: BD +18 2782 

Notes on dubious entries: Dubious Tycho proper motion: a Tycho proper motion component deviates more than 4 sigma from the PPM proper motion. Note that for most Tycho stars, however, SkyMap Pro displays ACT proper motion components; these have much greater accuracy than the original Tycho proper motion data.








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