NGC 2547

NGC 2547 is a southern open cluster in Vela, discovered by Nicolas Louis de Lacaille in 1751^[2][3] from South Africa. The star cluster is young with an age of 20-30 million years.^[4]

NGC 2547
This image from the Wide Field Imager on the MPG/ESO 2.2-metre telescope at ESO's La Silla Observatory in Chile, shows the bright open star cluster NGC 2547.
Observation data (J2000.0 epoch)
Right ascension	8h 09m 52.360s
Declination	−49° 10′ 35.01″
Distance	1.19 kly (364.0+46.8 −37.9[1] pc)
Apparent magnitude (V)	4.7
Apparent dimensions (V)	20′
Physical characteristics
Mass	201[1] M☉
Radius	2.61[1] ly
Estimated age	37.7+5.7 −4.8[1] Myr
Other designations	NGC 2547, Cr 177, Mel 84, Dunlop 410, Lacaille III.2
Associations
Constellation	Vela
See also: Open cluster, List of open clusters

Observations with the Spitzer Space Telescope showed a shell around the B3 III/IV-type star HD 68478. This could be a sign of recent mass loss in this star.^[5]

A study using Gaia DR2 data showed that NGC 2547 formed about 30 million years ago together with a new discovered star cluster, called [BBJ2018] 6.^[6][7] The star cluster NGC 2547 has a similar age compared with Trumpler 10, NGC 2451B, Collinder 135 and Collinder 140. It was suggested that all these clusters formed in a single event of triggered star formation.^[8]

NGC 2547 shows evidence for mass segregation down to 3 M_☉.^[9]

Cluster members with debris disks

Observations with the Spitzer Space Telescope have shown that ≤1% of the stars in NGC 2547 have infrared excess in 8.0 μm and 30-45% of the B- to F-type stars have infrared excess at 24 μm.^[10]

The system 2MASS J08090250-4858172, also called ID8 is located in NGC 2547 and showed substantial brightening of the debris disk at a wavelength of 3 to 5 micrometers, followed by a decay over a year. This was interpreted as a violent impact on a planetary body in this system.^[11]

NGC 2547 contains nine M-dwarfs with 24 μm excess. These could be debris disks and the material could be orbiting close to the snow line of these stars, indicating that planet-formation is underway in these systems.^[12] Later it was suggested that these M-dwarfs might contain Peter Pan Disks.^[13] 2MASS 08093547-4913033, which is one of the M-dwarfs with a debris disk in NGC 2547 was observed with the Spitzer Infrared Spectrograph. In this system the first detection of silicate was made from a debris disk around an M-type star.^[14]

Gallery

• 
  Asteroid collision - building planets near star NGC 2547-ID8 (artist concept)
• 
  Plot of IR brightness over time suggesting a collision of asteroids near star NGC 2547-0ID8 (2012–2013)
• Zooming into the open star cluster NGC 2547 (in HD)
• Pan sequence in the open star cluster NGC 2547 (in HD)
• 
  Infrared image of NGC 2547 taken with the Spitzer Space Telescope. Below the center HD 68478 and the shell around this star is seen.
• 
  Wide-field view of NGC 2547, created from DSS2 images.