J/A+A/696/A146 PN NGC2818A spectra (Fragkou+, 2025)
The physical association of planetary nebula NGC2818 with open cluster NGC2818A.
Fragkou V., Vazquez R., Parker Q. A., Goncalves D. R., Lomeli-Nunez L.
<Astron. Astrophys. 696, A146 (2025)>
=2025A&A...696A.146F 2025A&A...696A.146F (SIMBAD/NED BibCode)
ADC_Keywords: Planetary nebulae ; Spectra, optical ; Spectra, infrared
Keywords: white dwarfs - open clusters and associations: individual: NGC 2818A -
planetary nebulae: individual: NGC 2818
Abstract:
Planetary nebulae (PNe) that are physical members of open star
clusters (OC) provide us with highly valuable data for stellar
evolution studies. Unfortunately, they are extremely rare, with only
three such instances previously confirmed in our Galaxy.
In this study, we confirm the physical association of PN NGC 2818
with OC NGC 2818A, an association long debated in literature studies.
Hence, we add a fourth object in the sample of rare open cluster-PN
(OC-PN) pairs. The physical properties of the PN can then be linked to
those of its progenitor star.
Using GHOST at Gemini high-resolution nebular spectra, we measured the
PN systemic radial velocity to compare to that of the putative host
cluster. This is well determined from Gaia. We estimate the physical
parameters of both the OC NGC 2818A and the PN using our data,
together with estimates from previous studies and theoretical cluster
isochrones and evolutionary tracks to show they are compatible.
The highly precise determined systemic radial velocity of the PN is
consistent to within the small errors with that of the cluster and its
1km/s associated velocity dispersion. This is a tight and primary
requirement for cluster membership. We have determined other physical
parameters of the PN and cluster, such as age and distance. These also
match within the errors. Taken together, these results present
compelling evidence for the physical association of the PN and
cluster. The PN age was found to be around 11 kyr and the effective
temperature of its central star was estimated as 130 kK. The initial
and final masses of the progenitor star are determined to be
2.33±0.10M☉ and 0.58±0.10M☉ respectively. We plot the
resulting initial-to-final data point on the latest initial-
to-final-mass relation and also include the data points from our other
3 OC-PNe associations known. This new data point agrees with the
published trends from previous studies and further delineates the
"kink" found at relatively low initial masses.
We show that all 4 OC-PNe associations so far identified share a
number of common properties. These rare cases merit detailed
cluster-PNe studies and work to further extend the sample.
Description:
The GHOST spectral data for pointings a-k of the planetary nebula
NGC 2818A.
Objects:
----------------------------------------------------------
RA (2000) DE Designation(s)
----------------------------------------------------------
09 16 01.49 -36 37 37.5 NGC 2818A = PN G261.9+08.5
----------------------------------------------------------
File Summary:
--------------------------------------------------------------------------------
FileName Lrecl Records Explanations
--------------------------------------------------------------------------------
ReadMe 80 . This file
pointing.dat 45 11 List of pointings
point_a.dat 38 134568 The GHOST spectral data for pointing a
point_b.dat 38 134567 The GHOST spectral data for pointing b
point_c.dat 38 134568 The GHOST spectral data for pointing c
point_d.dat 35 134568 The GHOST spectral data for pointing d
point_e.dat 38 134567 The GHOST spectral data for pointing e
point_f.dat 38 134567 The GHOST spectral data for pointing f
point_g.dat 35 134567 The GHOST spectral data for pointing g
point_h.dat 35 134567 The GHOST spectral data for pointing h
point_i.dat 38 134567 The GHOST spectral data for pointing i
point_j.dat 38 134568 The GHOST spectral data for pointing j
point_k.dat 38 134568 The GHOST spectral data for pointing k
--------------------------------------------------------------------------------
Byte-by-byte Description of file: pointing.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 9 A9 --- Name Pointing name
11- 12 I2 h RAh Right ascension (J2000)
14- 15 I2 min RAm Right ascension (J2000)
17- 20 F4.1 s RAs Right ascension (J2000)
22 A1 --- DE- Declination sign (J2000)
23- 24 I2 deg DEd Declination (J2000)
26- 27 I2 arcmin DEm Declination (J2000)
29- 33 F5.2 arcsec DEs Declination (J2000)
35- 45 A11 --- FileName Name of the spectrum file
--------------------------------------------------------------------------------
Byte-by-byte Description of file: point_?.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 18 F18.13 nm lambda Wavelength
22- 38 E17.12 ct Flux Flux
-------------------------------------------------------------------------------
Acknowledgements:
Vasiliki Fragkou, vfragkou(at)ov.ufrj.br
(End) Patricia Vannier [CDS] 19-Mar-2025