1 Geminorum — Double Star in Gemini
Observe
1Physical Properties
Magnitude
4.16
Spectral Type
G7III
giant
Star Color
Orange
(B-V 0.82)
Distance
105 ly
2Position & Identifiers
RA
06h 04m 07.2s
Dec
+23° 15' 48.0"
Constellation
Gemini
(Gem)
HR
2134
HIP
28734
HD
41116
SAO
77915
Flamsteed
1 Gem
Variable ID
Var?
Querying VizieR catalog...
3How easy to spot?
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| Equipment | Bortle 3 | Bortle 4 | Bortle 5 |
|---|---|---|---|
| Naked eye Naked eye | Medium+ | Medium+ | Medium |
| 50 mm finder 50mm finder | Easy | Easy | Easy |
| 150 mm telescope 150mm scope | Easy | Easy | Easy |
Easy
Medium
Hard
Very hard
Impossible
Bortle 3 = rural · 4 = outer suburbs · 5 = suburbs
4Visibility
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Best season
Nov – Jan
(peak: Dec)
5Multiple Star System Quadruple C: optical
Components
4 (quadruple)
Component IDs
AB
Separation
0.2″
Companion Mag
5.5
Position Angle
358°
Star Colors
A: Orange
Discoverer
KUI 23
AB 4.7 G6III, 5.1 G8III, 13.17y, a = 0.19". Combined mag., colors. Component A is SB, 4.9, 6.9v, sep. 0.0013". | Speckle interferometric sep. 0.128" 1982.17, 0.086" 1983.93. Component C, 13.0v at 101".
Separation over time
Period: 13.3 y
Eccentricity: 0.361
Now: 0.23", PA 165°
-0.05" in 5 years
Apparent separation over time, computed from ORB6 orbital elements. Steep curves indicate fast-changing pairs — catch them while they're splittable.
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7
Size Comparison
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8
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9
Spectral Classification
10
Hertzsprung-Russell Diagram
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11
Stellar Lifecycle
12
Blackbody Spectrum
13
Stellar Absorption Spectrum
Simulated absorption spectrum based on spectral type. Hover over lines to identify elements.
14
Stellar Fusion
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15Stellar Notes
Comp. B of double; 9.5966d, K 51.7k/s, V0 +31.7k/s, asini 6.82.
Propus, a name more commonly applied to HR 2216.
16
Light Travel Time Machine
17
Relativistic Travel
Nearby in the Sky
Other targets within a few degrees — pan your scope a little and keep exploring.
Visibility scores assume a 150 mm Newton at Bortle 4.
NGC 2129
Rich open cluster
Open Cluster
mag 6.7
0.7°
Gemini
3 Gem
Variable star, range 7.0–10.0
Variable Star
mag 5.75
1.3°
Gemini
Propus
HIP 29655; Eta Geminorum; 7 Geminorum
Tight double — a rewarding split at 1.9″
Double Star
mag 3.28
2.6°
Gemini
Tejat Posterior
HIP 30343; Mu Geminorum; 13 Geminorum
Cool red giant
Double Star
mag 2.88
4.4°
Gemini
M1
Crab Nebula
Supernova remnant
Supernova Remnant
mag 8.4
6.9°
Taurus
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