Arp273 is actually a group of interacting galaxies with a projected nuclear separation of 40 kpc or 1.3x10⁴ light years. ¹. The two galaxies that make up Arp 273 are known independently as UGC01810 and UGC01813. UGC01810 is the larger more face on spiral galaxy and UGC01813 is the one that looks in this image to be smaller and flatter (it is in fact a spiral like UGC01810).

UGC01810: RA:2h21m28.700s Dec:+39deg22'31.90" Epoch:J2000 2 Classification: SA(s)b pec Diameters: Bluesize (POSS blue print) 2.1x1.4 arcmin 3 Red size (POSS red print) 1.9x1.3 arcmin 3 Apparent Total Magnitude (B): 13.5 +/-less than .3mag 4 Colour: B-V= 0.047 mag 5 Red shift: 0.02523 +/-0.00004 6 Distance: Between 7.569 & 15.138 Mpc * which is equivalent to it being between 24.69 and 49.38 million light years away.++ Heliocentric radial velocity: 7563 +/-11 km/s 5 Group association: Part of the Percius Cluster7

UGC01813: RA: 2h18m27.536s Dec: +39deg21'24.60" Epoch: J2000 2 Classification: SB(s)a pec Diameters: Bluesize (POSS blue print) 1.4x0.4 arcmin 3 Red size (POSS red print) 1.4x0.4 arcmin 3 Apparent Total Magnitude (B): 15.2+/-less than 0.3mag4 Colour: B-V= 0.68 mag 5 Red shift: 0.02447 +/-0.00015 6 Distance: Between 7.341 & 14.682 Mpc * which is equivalent to it being between 23.946 and 47.893 million light years away.++ Heliocentric radial velocity: 7335 +/-46 km/s Group association: Part of the Percius Cluster 7

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* distance=0.01zc/h
z is the redshift, c is the speed of light & h represents the hubble constant and is known to be between 0.5 & 1.0

++ 1 parsec=3.262 light years (http://www.astro.virginia.edu/~jh8h/glossary/parsec.htm)

Note: All references taken from NED unless otherwise indicated

1. Bernlohr, K. 'Models and observations of starbursts, II. Starbursts in interacting galaxies' Astron. Astrophys. 268, 25-34, 1993

   
   

2. Two Micron All Sky Survey Team (2Mass) Extended Objects. Release 2, 2000

   
   

3. Nilson, P. Uppsala General Catalogue of Galaxies, 1973, Acta Universitatis Upsalienis, Nova Regiae Societatis Upsaliensis, Series V:A Vol. 1

   
   

4. (PGC catalog) An extragalactic database. I - The Catalogue of Principal Galaxies Paturel, G.; Fouque, P.; Bottinelli, L.; Gouguenheim, L. Astronomy and Astrophysics Supplement Series (ISSN 0365-0138), vol. 80, no. 3, Nov. 1989, p. 299-315

   
   

5. (PGC LEDA) LEDA=Lyon-Meudon Extragalactic Database
   found at: http://leda.univ-lyon1.fr/cgi-bin/querybyname.pl?donnee=mean&objname=PGC+%2B008961

   
   

6. De Vaucouleurs, G., De Vaucouleurs, A., Corwin Jr., H.g., Buta, R.J. Paturel, G., and Fouque, P. Third reference Catalogue of Bright Galaxies. Version 3.9

   
   

7. Gregory, S. A.; Thompson, L. A.; Tifft, W. G. 'The Perseus supercluster' Astrophysical Journal, Part 1, vol. 243, Jan. 15, 1981, p. 411-426
   http://nedwww.ipac.caltech.edu/cgi-bin/nph-ex_refcode?refcode=1981ApJ...243..411G