Rho Arietis — Variable Star in Aries
HIP 13654; Rho2 Arietis; 45 Arietis
Good (55/100)
Observe
1Physical Properties
Magnitude
5.91
Range
5.45 - 6.01
Period
56 days
Variable Type
Semi-Regular Variable (Late-type Giant)
Spectral Type
M6-III:
Star Color
Red
(B-V 1.47)
Distance
233 ly
2Position & Identifiers
RA
02h 55m 48.5s
Dec
+18° 19' 54.0"
Constellation
Aries
(Ari)
HR
867
HIP
13654
HD
18191
SAO
93189
Bayer
Rho2
Flamsteed
45 Ari
Variable ID
RZ Ari
Querying VizieR catalog...
3How easy to follow?
Magnitude
5.6 – 6.0 mag
Amplitude
0.4 mag
Period
56.5 d
Type
SRB
Sign in
and configure your equipment and default location to see a personalized row.
| Equipment | Bortle 3 | Bortle 4 | Bortle 5 |
|---|---|---|---|
| Naked eye Naked eye | V. hard+ | V. hard | V. hard |
| 50 mm finder 50mm finder | Hard+ | Hard+ | Hard+ |
| 150 mm telescope 150mm scope | Hard+ | Hard+ | Hard+ |
Easy
Medium
Hard
Very hard
Impossible
Bortle 3 = rural · 4 = outer suburbs · 5 = suburbs
Out of reach for typical amateur telescopes, even at Bortle 3.
4Visibility
Set a location in User Settings to see visibility data.
Best season
Sep – Nov
(peak: Oct)
5Survey Image
Loading survey image…
6Light Curve
7Comparison Stars for Rho Ari (5.6–6.0)
Nearby stable stars for estimating brightness (AAVSO)
Loading comparison stars…
Explore
8
Size Comparison
Querying VizieR for stellar data…
9
Compare Stars
10
Spectral Classification
11
Hertzsprung-Russell Diagram
Loading HR diagram…
12
Stellar Lifecycle
13
Blackbody Spectrum
14
Stellar Absorption Spectrum
Simulated absorption spectrum based on spectral type. Hover over lines to identify elements.
15
Stellar Fusion
Discover
16Stellar Notes
SRb 5.62 - 6.01V, 30d.
Rho1 Fl 44, Rho2 Fl 45, Rho3 Fl 46 Ari are, respectively, HD 18091 (6.93v, A3), HR 867 and 869. HR 869 is | also called simply Rho Ari.
Occultation diam. = 0.0095 - 0.012".
17
Light Travel Time Machine
18
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.
Explore Nightbase
Related knowledge, tools, and stories — no observation planning required.
Arthur Eddington
1919 eclipse expedition confirming general relativity; first theory of stellar interiors; the Eddington limit
Biography
Variable Stars — A Guide for Observers
A practical guide to visual observation of variable stars: estimating magnitudes, finding comparison stars, recording data, and contributing to science with AAVSO.
Article
Aries
Mythology, bright stars, and deep-sky highlights.
Constellation
