Ukuran asli (4.198 × 3.881 piksel, ukuran berkas: 18,14 MB, tipe MIME: image/jpeg)
Berkas ini berasal dari Wikimedia Commons dan mungkin digunakan oleh proyek-proyek lain.
Deskripsi dari halaman deskripsinya ditunjukkan di bawah ini.
Ringkasan
DeskripsiCaldwell 17 (50290241446).jpg
Caldwell 17, also known as NGC 147, is a dwarf galaxy located roughly 2.5 million light-years from Earth. It is a member of the Local Group of galaxies, which is dominated by our Milky Way and the Andromeda galaxy. Caldwell 17, like its neighbor Caldwell 18, is a distant satellite of the Andromeda galaxy. Just as the planets in the solar system are gravitationally bound to the Sun, so are these smaller galaxies bound to their much more massive galactic host. While many classes of galaxies can exist as satellites, dwarf spheroidal galaxies (small, dim, spherical-shaped galaxies) like Caldwell 17 have been observed in this role more frequently than any other type of galaxy.
Dwarf satellite galaxies tend to appear very diffuse and dim, so they can be difficult to spot (especially in light-polluted or hazy skies). Caldwell 17 is no exception. It has an apparent magnitude of 9.5, and observers will need a small telescope set up in a dark location to detect the faint galaxy. Caldwell 17 is located in the southern edge of the constellation Cassiopeia, between the constellation’s “W” pattern and the Andromeda galaxy. (The neighboring Caldwell 18 is brighter and less diffuse, so it is easier to see.) The best time of year to spot Caldwell 17 from the Northern Hemisphere is the autumn. It can also be seen in northern latitudes of the Southern Hemisphere in the spring. The galaxy was discovered by the English astronomer John Herschel in September of 1829.
This image of Caldwell 17 is a composite of observations made in visible and infrared light by Hubble’s Wide Field Camera 3. The image captures an area near the core of the galaxy, which is notable for its elderly stellar population. Astronomers used Hubble’s observations to investigate the properties of Caldwell 17’s many globular star clusters.
Credit: NASA, ESA, and A. Ferguson (University of Edinburgh, Institute for Astronomy); Processing: Gladys Kober (NASA/Catholic University of America)
For Hubble's Caldwell catalog website and information on how to find these objects in the night sky, visit: <a href="https://www.nasa.gov/content/goddard/hubble-s-caldwell-catalog" rel="noreferrer nofollow">www.nasa.gov/content/goddard/hubble-s-caldwell-catalog</a>
untuk berbagi – untuk menyalin, mendistribusikan dan memindahkan karya ini
untuk menggubah – untuk mengadaptasi karya ini
Berdasarkan ketentuan berikut:
atribusi – Anda harus mencantumkan atribusi yang sesuai, memberikan pranala ke lisensi, dan memberi tahu bila ada perubahan. Anda dapat melakukannya melalui cara yang Anda inginkan, namun tidak menyatakan bahwa pemberi lisensi mendukung Anda atau penggunaan Anda.
https://creativecommons.org/licenses/by/2.0CC BY 2.0 Creative Commons Attribution 2.0 truetrue
Berkas ini mengandung informasi tambahan yang mungkin ditambahkan oleh kamera digital atau pemindai yang digunakan untuk membuat atau mendigitalisasi berkas. Jika berkas ini telah mengalami modifikasi, rincian yang ada mungkin tidak secara penuh merefleksikan informasi dari gambar yang sudah dimodifikasi ini.