Credit: Aldo Zanetti
Astronomical and Imaging Data
| RA: | 04h 46m 05.91s |
| DEC: | +31° 22′ 53.4″ |
| MAG: | 13.04 |
| Diameter: | 2.2′ |
| Const: | Aur |
| OTA | Celestron 9.25 Edge HD |
| Focal Length | 2350 |
| Camera | ASI1600MM |
| Site | Northern Italy |
| Sky Quality | Bortle 7 |
Useful Informations
Palomar 2 is a distant and heavily obscured globular cluster belonging to the Milky Way’s outer halo. It is a scientifically significant object because its hidden location offers unique insights into the structure and history of our galaxy.
Key Physical Characteristics
Palomar 2 is classified as a loose globular cluster, falling under the Shapley–Sawyer concentration class IX (where I is the most concentrated and XII is the least).
- Location and Obscuration: It is found in the northern constellation Auriga and is one of the 15 faint Palomar globular clusters discovered in the 1950s. Its key characteristic is its high level of obscuration; it lies behind both the Perseus and Norma/Outer arms of the Milky Way. This dust veiling dims its light by nearly three full magnitudes, which is why it was discovered relatively late and appears as a faint burst of stars. Its high absorption by interstellar gas causes its stars to appear significantly reddened.
- Distance and Position: Palomar 2 is a distant stellar system. Its estimated distance from the Sun is about 27 kiloparsecs (around 85,000 light-years), placing it far out in the outer halo of the Milky Way. This location is unusual as it is in the direction of the Galactic anti-center (opposite to the Galactic center), placing it much farther from the galactic center than most other clusters.
- Age and Metallicity: Palomar 2 is an ancient cluster, with an estimated age of about 13.25 billion years. Its stars are considered metal-poor with a metallicity value [Fe/H] near −1.39 to −1.6, consistent with other old globular clusters.
- Mass and Luminosity: The cluster is estimated to have a mass of approximately 1.4×105 solar masses and an absolute magnitude (MV) of about −7.8, making it one of the brighter and more massive clusters in the outer halo despite its faint appearance.
- Kinematics: The cluster has a high radial velocity of approximately −134.9 km/s, meaning it’s moving towards us relative to the Sun.