HCG 87

HCG 87
HCG 87
	400 million
Other designations
	None
	See also: Galaxy group, Galaxy cluster, List of galaxy groups and clusters

HCG 87 is a compact

400 million light-years away ^[2] in the constellation Capricornus

. The group distinguishes itself as one of the most compact groups of galaxies, hosting two active galactic nuclei and a starburst among its three members, all of which show signs of interaction.^[3] This interaction, which astronomers have called visually, and scientifically, intriguing^[4] is being examined to understand the influence of active nuclei on star formation histories.

Members

**Members of the HCG 87**
Name	Type^[5]	J2000)^[5]	J2000)^[5]	Redshift (km/s)^[5]	Apparent Magnitude^[5]
HCG 87a	S0 pec	20^h 48^m 15.0^s	−19° 50′ 58″	8443 ± 14	15.3
HCG 87b	SA(r)0 pec	20^h 48^m 10.9^s	−19° 51′ 23″	8740 ± 20	15.4
HCG 87c	Sb	20^h 48^m 12.0^s	−19° 49′ 56″	8914 ± 7	16.1
HCG 87d	Sd	20^h 48^m 12.8^s	−19° 50′ 46″	10200 ± 160	17.8

External links

Astronomy Picture of the Day
- Galaxy Group HCG 87 – 2003 July 31
- HCG 87: A Small Group of Galaxies – 2010 July 6
Close-ups of HCG 87
Galactic Clusters
Studies of Hickson Compact Groups

References

^ ^a ^b ^c "NASA/IPAC Extragalactic Database". Results for HCG 87. Retrieved 2006-10-19.
^ This redshift corresponds to a distance of 120Mpc or 400 million light years (using H₀ = 75km/s/Mpc and q₀ = 0.1). At the distance of the group, this corresponds to a group diameter of 52kpc, i.e., the group is approximately 170,000 light years across.
^ Noll, Keith. 07/1999. "Hubble Heritage observations of Hickson Compact Galaxy Group 87".
^ English, J. et al. 05/2000. "A Minuet of Galaxies: Hickson Compact Group 87 as Viewed by the Hubble Space Telescope". American Astronomical Society, 195th AAS Meeting, #136.04; Bulletin of the American Astronomical Society, Vol. 32, p.884.
^ ^a ^b ^c ^d ^e "NASA/IPAC Extragalactic Database". Results for various galaxies. Retrieved 2006-10-19.

Stars

Bayer	α¹ (Prima Giedi) α² (Algedi) β¹ (Dabih) β² γ (Nashira) δ (Deneb Algedi) ε ζ η θ ι κ λ μ ν (Alshat) ξ¹ ξ² ο¹ ο² π ρ σ τ¹ τ² υ φ χ ψ ω
Flamsteed	3 4 17 19 20 21 24 (A) 27 29 30 31 33 35 36 (b) 37 41 42 44 45 46 (c) 47 (c²) 50
Variable	R
HR	7722 7845 7898
HD	197027 202206 204313
Other	HATS-3 LP 816-60

Exoplanets	HD 192310 b c HD 202206 c HD 204313 b HD 202772 Ab PSO J318.5−22

Star clusters	Messier 30 Palomar 12

Galaxies

NGC	6907 7016 7019 7030 7035 7035A 7073
Other	IC 1337

Galaxy clusters	HCG 87

Category

v t e Galaxies
Morphology	Disc Lenticular barred unbarred Spiral anemic barred flocculent grand design intermediate Magellanic unbarred Dwarf galaxy elliptical irregular spheroidal spiral Elliptical galaxy cD Irregular barred Peculiar Ring Polar
Structure	Active galactic nucleus Bar Bulge Central massive object Galactic Center Dark matter halo Disc Disc galaxy Halo corona Galactic plane Galactic ridge Interstellar medium Protogalaxy Galaxy filament Spiral arm Supermassive black hole Ultramassive
Active nuclei	Blazar LINER Markarian Quasar BL Lacertae object Radio X-shaped DRAGN Relativistic jet Seyfert
Energetic galaxies	Lyman-alpha emitter Lyman-break Luminous infrared ULIRG HLIRG ELIRG Starburst blue compact dwarf pea faint blue Luminous infrared galaxy Hot dust-obscured Green bean galaxy Hanny's Voorwerp Wolf-Rayet galaxy
Low activity	Low surface brightness Ultra diffuse Dark galaxy Red nugget Blue Nugget Dead disk
Interaction	Field Galactic tide Groups and clusters group cluster Brightest cluster galaxy fossil group Interacting merger collision cannibalism Jellyfish Satellite Stellar stream Superclusters Walls Voids and supervoids void galaxy
Lists	Galaxies Galaxies named after people Largest Nearest Polar-ring Ring Spiral Groups and clusters Large quasar groups Quasars List of the most distant astronomical objects Starburst galaxies Superclusters Voids
See also	Extragalactic astronomy Galactic astronomy Galactic coordinate system Galactic habitable zone Galactic magnetic fields Galactic orientation Galactic quadrant Galaxy color–magnitude diagram Galaxy formation and evolution Galaxy rotation curve Gravitational lens Gravitational microlensing Illustris project Intergalactic dust Intergalactic stars Intergalactic travel Population III stars Galaxy X (galaxy)
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