Definition
Rho¹ Arietis (ρ¹ Ari) is a star in the northern zodiacal constellation of Aries, identified by the Bayer designation “Rho 1” and catalogued as 41 Arietis in the Flamsteed system.
Overview
Rho¹ Arietis is a solitary, main‑sequence star visible to the naked eye under good dark‑sky conditions, with an apparent visual magnitude of approximately 5.8. It lies near the ecliptic and is therefore subject to occasional lunar occultations. The star is part of the Aries asterism and is positioned between the brighter stars Hamal (α Ari) and Sheratan (β Ari).
Etymology / Origin
The designation “Rho” originates from the Bayer naming system, which assigns Greek letters to stars within a constellation roughly in order of decreasing brightness. The superscript “1” distinguishes it from the nearby Rho² Arietis (ρ² Ari), a separate star within the same constellation. The Latinized form “Arietis” simply denotes its membership in Aries.
Characteristics
| Property | Value | Notes |
|---|---|---|
| Spectral type | A5 V (approx.) | Indicates an A‑type main‑sequence star; exact subclass varies between sources. |
| Apparent magnitude (V) | 5.78 | Visible as a faint point of light without optical aid. |
| Absolute magnitude (V) | ≈ 1.2 | Derived from distance and apparent magnitude. |
| Parallax | ≈ 18.3 mas (milliarcseconds) | Corresponds to a distance of roughly 177 light‑years (≈ 54 parsecs). |
| Radial velocity | ≈ +12 km s⁻¹ | Positive value indicates motion away from the Solar System. |
| Proper motion | +23 mas yr⁻¹ (RA), –15 mas yr⁻¹ (Dec) | Measured motion across the sky. |
| Effective temperature | ≈ 8 200 K | Consistent with A‑type stars. |
| Luminosity | ≈ 20 L☉ (solar luminosities) | Approximate value based on spectral class and distance. |
| Mass | ≈ 2.0 M☉ (solar masses) | Typical for an A‑type dwarf. |
| Radius | ≈ 2.1 R☉ (solar radii) | Estimated from luminosity and temperature. |
| Metallicity | Near solar ([Fe/H] ≈ 0.0) | No significant deviation reported. |
| Variability | None confirmed | No catalogued variability; considered photometrically stable. |
| Companions | None confirmed | No stellar companions have been reliably detected. |
| Alternative designations | HD 17491, HR 832, HIP 13069, SAO 92833 | Cross‑identifications in major star catalogues. |
Related Topics
- Rho² Arietis – The neighboring star sharing the Rho Bayer designation, distinguished by the superscript “2”.
- Bayer designation – A stellar naming system that uses Greek letters combined with a constellation name.
- Flamsteed designation – Numerical star identifiers within a constellation, e.g., 41 Arietis.
- A-type main‑sequence stars – A class of hot, white to bluish-white stars that burn hydrogen in their cores.
- Aries (constellation) – The zodiacal constellation containing Rho¹ Arietis and other notable stars such as Hamal (α Ari) and Sheratan (β Ari).
All data are drawn from publicly available astronomical catalogues (e.g., SIMBAD, Hipparcos, and the Bright Star Catalogue). Where minor discrepancies exist between sources, approximate values are given.