Theta Tau
HIP 20885; Theta1 Tau; 77 Tau
Observable Double Star
Good (49/100)
Sep: 337.4", Companion: mag 7.3
HIP 20885; Theta1 Tau; 77 Tau
DoubleStar
Tau
Visible
Level 2
Small telescope (4") - Requires steady seeing
Physical Properties
Magnitude
3.84
Spectral Type
G9III Fe-0.5
Star Color
Orange
(B-V 0.95)
Distance
154.3 ly
Position & Identifiers
RA
04h 28m 34.5s
Dec
+15° 57' 44.0"
Constellation
Tau
HR
1411
HIP
20885
Bayer
Theta1
Flamsteed
77 Tau
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Visibility
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Multiple Star System
Components
4
Component IDs
AB
Separation
337.4″
Companion Mag
7.3
Position Angle
351°
Star Colors
A: Orange
B: Yellow-white
Eyepiece View
32x
Dawes: 1.9″
TFOV: 1.6°
Realistic = true angular size
Sep: 337.4″ · PA: 351° · N up, E left
Resolved · Rayleigh: 2.3″ · Dawes: 1.9″ · Eff: 3.1″
Size Comparison
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Stellar Lifecycle
Spectral Classification
Hertzsprung-Russell Diagram
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Blackbody Spectrum
Stellar Absorption Spectrum
Simulated absorption spectrum based on spectral type. Hover over lines to identify elements.
Stellar Notes
CPM with HR 1412. Not clear if there are one or two occultation companions: mag. diff 3.8v, sep. 0.082", another | possible mag. diff 8v, sep. 0.2".
6000 or 3000d. Unresolved by speckle interferometry 1983.93.
Color excess E(B-V) = +0.09.
In Hyades cluster; Mel 25 #71.
Diam. 0.0026".
Survey Image
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