Planetary Nebula Merrill 2-1 + Galaxy IC 4538

Merrill 2-1
Merrill 2-1: Image taken with Hubble Space Telescope. © ESA/Hubble & NASA, Judy Schmidt [165]

History

This small planetary nebula Me 2-1 was discovered in 1942 by the American astronomer Paul Willard Merrill while looking through objective-prism photographs taken in 1940 by William C. Miller with the 10-inch telescope on Mount Wilson Observatory. The nebula showed a distinct bright Hα line. He also discovered a second planetary nebula (Me 2-2 in Lacerta). The discovery was confirmed by slit spectrograph pictures taken in 1941 with the 100 inch telescope. Both showed the chief nebular lines to be strong. He described the planetary nebula as a disk with 6 arcseconds in diameter and without a conspicuous nucleus. [526]

Physical Properties

According to Simbad the distance is 6665 pc (21'738 lightyears). The apparent brightness in different bands is: B 12.2 mag, V 12.20 mag, G 18.35 mag, J 13.78 mag, H 13.95 mag, K 13.16 mag. [145]

About 45 arcseconds west of Me 2-1, is the binary star CD-23 12237 (SAO 183407) with a visual magnitude of 9.8 mag. It is an orange star of spectral class K2. It's partner is only 0.1 arcseconds separated. The distance is given with 454-533 pc, so it is much closer and is not related to the PN. [145, 149]

«Strasbourg-ESO Catalogue of Galactic Planetary Nebulae» Acker et al., 1992 [141]
Designations PN G342.1+27.5: Me 2-1, PK 342+27.1, ARO 88, ESO 514-12, He 2- 126, Sa 2- 120, StWr 4- 2, VV 72, VV' 124, Wray 16- 176, Y-C 2-18
Right Ascension (J2000.0) 15h 22m 19s
Declination (J2000.0) -23° 37' 31"
Dimensions 6." (optical), 7." (radio)
Radial Velocity +45.5 ± 5.3 km/s
Expansion Velocity 13.0 (O-III) km/s
C-Star Designations AG82 178, CD -23 12238
C-Star Magnitude B: 18.85
C-Star Spectral Type IUE Sp.,P Cyg
Discoverer MERRILL 1942

Galaxy IC 4538

Merrill 2-1 + IC 4538
Merrill 2-1 + IC 4538: Section of PanSTARRS/DR1 color [147]

The spiral galaxy IC 4538 about 15 arcminutes west of Me 2-1 was already discovered on 26 May 1895 by the American astronomer Lewis Swift using the 16 inch Clark Refractor Warner Observatory, Rochester. [277]

Revised+Historic NGC/IC Version 22/9, © 2022 Dr. Wolfgang Steinicke [277]
Designation IC 4538
Type Gx (SBc)
Right Ascension (J2000.0) 15h 21m 11.6s
Declination (J2000.0) -23° 39' 30"
Diameter 2.6 × 2 arcmin
Photographic (blue) magnitude 12.8 mag
Visual magnitude 12.1 mag
Surface brightness 13.7 mag·arcmin-2
Position Angle 32°
Redshift (z) 0.009530
Distance derived from z 40.25 Mpc
Metric Distance 31.650 Mpc
Identification, Remarks ESO 514-10; MCG -4-36-13; UGCA 406; IRAS 15182-2328

Finder Chart

The planetary nebula Merrill 2-1 is located in the constellation Libra. The best observation time is in the months March to June.

Finder Chart Planetary Nebula Merrill 2-1 + Galaxy IC 4538
Planetary Nebula Merrill 2-1 + Galaxy IC 4538 in constellation Libra. Charts created using SkySafari 6 Pro and STScI Digitized Sky Survey. Limiting magnitudes: Constellation chart ~6.5 mag, DSS2 close-ups ~20 mag. [149, 160]

Objects Within a Radius of 15°

References