NGC 7217 - Misplaced Pages

Galaxy in the constellation Pegasus

NGC 7217
Spiral Galaxy NGC 7217 by HST, 1.62′ view
Observation data (J2000 epoch)
Constellation	Pegasus
Right ascension	22 07 52.4
Declination	+31° 21′ 33″
Redshift	952 ± 2 km/s
Distance	50.0 Mly
Apparent magnitude (V)	11.0
Characteristics
Type	(R)SA(r)ab
Apparent size (V)	3.9′ × 3.2′
Other designations
UGC 11914, PGC 68096

NGC 7217 is an unbarred spiral galaxy in the constellation Pegasus.

Features

NGC 7217 is a gas-poor system whose main features are the presence of several rings of stars concentric to its nucleus: three main ones –the outermost one being of the most prominent and the one that features most of the gas and star formation of this galaxy – plus several others inside the innermost one discovered with the help of the Hubble Space Telescope; a feature that suggests NGC 7217's central regions have suffered several starbursts. There is also a very large and massive spheroid that extends beyond its disk.

Other noteworthy features this galaxy has are the presence of a number of stars rotating in the opposite direction around the galaxy's center to most of them and two distinct stellar populations: one of intermediate age on its innermost regions and a younger, metal-poor version on its outermost ones.

It has been suggested these features were caused by a merger with another galaxy and, in fact, computer simulations show that NGC 7217 could have been a large lenticular galaxy that merged with one or two smaller gas-rich ones of late Hubble type becoming the spiral galaxy we see today; however right now this galaxy is isolated in space, with no nearby major companions. More recent research presents a somewhat different scenario in which NGC 7217's massive bulge and halo would have been formed in a merger and the disk formed later (and is still growing) either accreting gas from the intergalactic medium or smaller gas-rich galaxies, or most likely from a previously existing reserve.

References

^ "NASA/IPAC Extragalactic Database". Results for NGC 7217. Retrieved 2006-11-25.
^ Verdes-Montenegro, L.; Bosma, A. (1995). "The three rings of the isolated galaxy NGC 7217". Astronomy and Astrophysics. 300: 65. Bibcode:1995A&A...300...65V.
Combes, F.; García-Burillo, S.; Boone, F.; Hunt, L.K.; et al. (2004). "Molecular gas in NUclei of GAlaxies (NUGA). II. The ringed LINER NGC 7217". Astronomy and Astrophysics. 414 (3): 857–872. arXiv:astro-ph/0310652. Bibcode:2004A&A...414..857C. doi:10.1051/0004-6361:20031664. S2CID 12941641.
Buta, R.; van Driel, W.; Braine, J.; Combes, F.; et al. (1995). "NGC 7217: A Spheroid-dominated, Early-Type Resonance Ring Spiral Galaxy". The Astrophysical Journal. 450: 593. Bibcode:1995ApJ...450..593B. doi:10.1086/176169.
Merrifield, M.R.; Kuijken, K. (1994). "Counterrotating stars in the disk of the SAB galaxy NGC 7217". Astrophysical Journal. 432 (2): 575–589. Bibcode:1994ApJ...432..575M. doi:10.1086/174596. hdl:1887/92276.
^ Sil'Chenko, O.K.; Chillingarian, I.V.; Sotnikova, N.Y.; Afanasiev, Victor L. (2011). "Large-scale nested stellar discs in NGC 7217". Monthly Notices of the Royal Astronomical Society. 414 (4): 3645–3655. arXiv:1103.1692. Bibcode:2011MNRAS.414.3645S. doi:10.1111/j.1365-2966.2011.18665.x. S2CID 119299160.
Sil'Chenko, O.K.; Moiseev, A.V. (2006). "Nature of Nuclear Rings in Unbarred Galaxies: NGC 7742 and NGC 7217". The Astronomical Journal. 131 (6): 1336–1346. arXiv:astro-ph/0512431. Bibcode:2006AJ....131.1336S. doi:10.1086/499945. S2CID 14589261.
Fabricius, M. H.; Coccato, Lodovico; Bender, R.; Drory, N.; Gössl, C.; Landriau, M.; Saglia, R. P.; Thomas, J.; Williams, M. J. (2009). "Regrowth of stellar discs in mature galaxies: the two-component nature of NGC 7217 revisited with VIRUS-W". Monthly Notices of the Royal Astronomical Society. 441 (3): 2212–2229. arXiv:1404.2272. Bibcode:2014MNRAS.441.2212F. doi:10.1093/mnras/stu694. S2CID 119269888.

External links

NGC 7217 Archived 2009-06-03 at the Wayback Machine
http://atlas.zevallos.com.br/
NGC 7217 on WikiSky: DSS2, SDSS, GALEX, IRAS, Hydrogen α, X-Ray, Astrophoto, Sky Map, Articles and images

v t e Astronomical catalogs
NGC	NGC 7212 NGC 7213 NGC 7214 NGC 7215 NGC 7216 NGC 7217 NGC 7218 NGC 7219 NGC 7220 NGC 7221 NGC 7222
PGC	PGC 68092 PGC 68093 PGC 68094 PGC 68095 PGC 68096 PGC 68097 PGC 68098 PGC 68099 PGC 68100
UGC	UGC 11910 UGC 11911 UGC 11912 UGC 11913 UGC 11914 UGC 11915 UGC 11916 UGC 11917 UGC 11918

v t e New General Catalogue 7000 to 7499
7000 7001 7002 7003 7004 7005 7006 7007 7008 7009 7010 7011 7012 7013 7014 7015 7016 7017 7018 7019 7020 7021 7022 7023 7024 7025 7026 7027 7028 7029 7030 7031 7032 7033 7034 7035 7036 7037 7038 7039 7040 7041 7042 7043 7044 7045 7046 7047 7048 7049 7050 7051 7052 7053 7054 7055 7056 7057 7058 7059 7060 7061 7062 7063 7064 7065 7066 7067 7068 7069 7070 7071 7072 7073 7074 7075 7076 7077 7078 7079 7080 7081 7082 7083 7084 7085 7086 7087 7088 7089 7090 7091 7092 7093 7094 7095 7096 7097 7098 7099 7100 7101 7102 7103 7104 7105 7106 7107 7108 7109 7110 7111 7112 7113 7114 7115 7116 7117 7118 7119 7120 7121 7122 7123 7124 7125 7126 7127 7128 7129 7130 7131 7132 7133 7134 7135 7136 7137 7138 7139 7140 7141 7142 7143 7144 7145 7146 7147 7148 7149 7150 7151 7152 7153 7154 7155 7156 7157 7158 7159 7160 7161 7162 7163 7164 7165 7166 7167 7168 7169 7170 7171 7172 7173 7174 7175 7176 7177 7178 7179 7180 7181 7182 7183 7184 7185 7186 7187 7188 7189 7190 7191 7192 7193 7194 7195 7196 7197 7198 7199 7200 7201 7202 7203 7204 7205 7206 7207 7208 7209 7210 7211 7212 7213 7214 7215 7216 7217 7218 7219 7220 7221 7222 7223 7224 7225 7226 7227 7228 7229 7230 7231 7232 7233 7234 7235 7236 7237 7238 7239 7240 7241 7242 7243 7244 7245 7246 7247 7248 7249 7250 7251 7252 7253 7254 7255 7256 7257 7258 7259 7260 7261 7262 7263 7264 7265 7266 7267 7268 7269 7270 7271 7272 7273 7274 7275 7276 7277 7278 7279 7280 7281 7282 7283 7284 7285 7286 7287 7288 7289 7290 7291 7292 7293 7294 7295 7296 7297 7298 7299 7300 7301 7302 7303 7304 7305 7306 7307 7308 7309 7310 7311 7312 7313 7314 7315 7316 7317 7318 7319 7320 7321 7322 7323 7324 7325 7326 7327 7328 7329 7330 7331 7332 7333 7334 7335 7336 7337 7338 7339 7340 7341 7342 7343 7344 7345 7346 7347 7348 7349 7350 7351 7352 7353 7354 7355 7356 7357 7358 7359 7360 7361 7362 7363 7364 7365 7366 7367 7368 7369 7370 7371 7372 7373 7374 7375 7376 7377 7378 7379 7380 7381 7382 7383 7384 7385 7386 7387 7388 7389 7390 7391 7392 7393 7394 7395 7396 7397 7398 7399 7400 7401 7402 7403 7404 7405 7406 7407 7408 7409 7410 7411 7412 7413 7414 7415 7416 7417 7418 7419 7420 7421 7422 7423 7424 7425 7426 7427 7428 7429 7430 7431 7432 7433 7434 7435 7436 7437 7438 7439 7440 7441 7442 7443 7444 7445 7446 7447 7448 7449 7450 7451 7452 7453 7454 7455 7456 7457 7458 7459 7460 7461 7462 7463 7464 7465 7466 7467 7468 7469 7470 7471 7472 7473 7474 7475 7476 7477 7478 7479 7480 7481 7482 7483 7484 7485 7486 7487 7488 7489 7490 7491 7492 7493 7494 7495 7496 7497 7498 7499
Astronomical catalog List of NGC objects 7001–7840

New General Catalogue 7000 to 7499

Categories:

Features

See also

References

External links