1 Do post-common envelope objects form a distinct subset of PNe? David J. Frew Perth Observatory & Macquarie University Q.A. Parker and the MASH Collaboration Asymmetrical Planetary Nebulae IV La Palma, 21 June 2007

2 The Solar Neighbourhood Sample…   Database of ‘potentially nearby’ PNe   Improved integrated fluxes in H  and [OIII]   Combination of literature and new spectroscopic data, kinematic data, and CSPN photometry   Using revised/new distances, define a volume- limited sample within 1.0 kpc (presently, n = 53)   Extending sample volume to 1.5 kpc and 2.0 kpc (in progress)

3 FP (Frew et al., in prep.) 30' PFP 1 (Pierce et al. 2004) RCW 24 (Frew et al. 2006) FP (Frew et al., in prep.) 30’ New giant PNe in the solar neighbourhood

4 Planetary nebula or ionized ambient ISM…  Sh 2-174, DeHt 5, RE , Sh 2-68, HDW 5…  PG , PG , KPD , Hewett 1…  PHL 932, EGB 5…  … are not bona fide PNe, but simply ionized ‘Strömgren spheres’ in ambient ISM  Can conclude that no DO white dwarf is physically associated with a PN  No sdB/sdOB (AGB-manqué) star has an associated ejecta nebula or ‘PN’

5 H  SB – radius relation All calibrators (n = 114) log S(H  )= -3.42(±0.21)log R – 5.23(±0.16)

6 High-excitation PNe (n = 16) Close-binary PNe (n = 11) High-excitation PNe (n = 16) Close-binary PNe (n = 11) HE PNe: squares CE PNe: triangles Others: crosses Increasing mass M  S(H  ) ½

‘ Large high-excitation PNe’ (Kaler 1981) Round, elliptical, or amorphous (filled-centre) morphologies Large expansion velocities RT instabilities often seen Very high excitation: HeII 4686 ≥ 0.75 H  and very weak or absent [O II], [N II] and [S II] emission CS is hot (T eff > 100 kK), and luminous relative to nebular flux Large scale height, |z| = 340 pc Low ionized masses ≤ 0.25 M 

8 The post-common envelope PN sample 23 close-binary PNe from De Marco (2006, IAU Symp. 234) 23 close-binary PNe from De Marco (2006, IAU Symp. 234) Removed Abell 35, NGC 6302 and Sh 2-71 Removed Abell 35, NGC 6302 and Sh 2-71 LoTr 5 and NGC 1514 are included, but have unknown orbital periods LoTr 5 and NGC 1514 are included, but have unknown orbital periods Also added NGC 1360 (Bond & Afsar 2005) Also added NGC 1360 (Bond & Afsar 2005) Sample of 21 objects Sample of 21 objects Selected 11 PNe with reliable distances and flux data, as calibrating objects Selected 11 PNe with reliable distances and flux data, as calibrating objects

9 Sh 2-71 does not have a close binary nucleus… The true CS has been misidentified in the literature The true CS (m B ≈ 19) is directly at centre (arrowed) Credit: Adam Block / KPNO

10 Calibrating post-common envelope PNe PN Distance (kpc) Method Mass (M  ) HFG 1 HFG 1 # 0.6 ± 0.3 spectroscopic parallax 0.5: NGC ± 0.10 spect. parallax 0.03 NGC ± 0.2 spect. parallax, extinction 0.06 LoTr ± 0.2 spect. par., Wilson-Bappu, trig SBS A 18 ± 5 gravity method 0.17 SuWt ± 0.4 spect. parallax 0.06 DS 1 DS 1 # 0.73 ± 0.07 reflection effect 0.26 BE UMa BE UMa # 2.0 ± 0.4 reflection effect 0.2: Abell ± 0.6 eclipsing binary 0.14 Abell ± 0.4 eclipsing binary 0.08 NGC 1360 * NGC 1360 # * 0.38 ± 0.2 Gravity, trig. parallax 0.13 # High excitation * Inferred close binary (Afsar & Bond 2005)

11 Post-CE PNe: Morphologies ‘Filled-centre’ ellipticalsBipolar and toroidal rings, …but no double-shell ellipticals NGC 2346 PHR NGC 1360NGC 6578 NGC 5979Abell 65SuWt 2Shapley 1 DSS. Credit: H. Bond / HST/ NASA AAO/UKST Survey Credit: ESA/ESO/NASA AAO/UKST Survey ?

12 Post-CE PNe: Properties SB(H  ) = –2.5 to –6.0 erg cm -2 s -1 sr -1 (+0.2 to –6.7) SB(H  ) = –2.5 to –6.0 erg cm -2 s -1 sr -1 (+0.2 to –6.7) Average ionized mass (post-CE PNe) = 0.17 ± 0.13 M  Average ionized mass (post-CE PNe) = 0.17 ± 0.13 M  Average ionized mass (post-CE PNe, excluding HFG 1) = 0.13 ± 0.08 M  Average ionized mass (post-CE PNe, excluding HFG 1) = 0.13 ± 0.08 M  Average ionized mass = 0.64 ± 0.5 M  (non post-CE local PNe, restricted range of SB) Average ionized mass = 0.64 ± 0.5 M  (non post-CE local PNe, restricted range of SB) Post-CE PNe have low ionized masses. Extends conclusion of Bell et al. (1994) re Abell 63 Post-CE PNe have low ionized masses. Extends conclusion of Bell et al. (1994) re Abell 63

13 Binarity of CSPN: optical/near-IR colours (2MASS and/or DENIS) ~53 PNe in solar neighbourhood (d ≤ 1.0 kpc) ~7 wide binaries, e.g. Ciardullo et al (6/6 with 2MASS data show excess at J, H and/or K) ~7 close binaries (4 have periods; 5/6 in 2MASS show excess at J, H and/or K) 3 more CSPN have excess at J, H and/or K 16 show no IR excess 21 PNe have no observational data Of the 32 PNe with optical/near IR colours, total binary fraction ≈ 53% (agrees with Duquennoy & Mayor) total close-binary fraction ≈ 13 − 31%

14 Selection bias? 2MASS photometry limit at J ≈ 16, K s ≈ 15 2MASS photometry limit at J ≈ 16, K s ≈ 15 Detection limit for CS companion is M0V – M8V, depending on luminosity of CSPN Detection limit for CS companion is M0V – M8V, depending on luminosity of CSPN Alternatively, CS may have brown dwarf or cool WD companion, or be a merger product... Alternatively, CS may have brown dwarf or cool WD companion, or be a merger product... … but recall the Brown Dwarf Desert (e.g. Marcy & Butler 2000, Armitage & Bonnell 2002, Grether & Lineweaver 2006). … but recall the Brown Dwarf Desert (e.g. Marcy & Butler 2000, Armitage & Bonnell 2002, Grether & Lineweaver 2006). Solar-type stars (i.e. PN progenitors) have an almost total absence of brown dwarf companions within 5 AU !! Solar-type stars (i.e. PN progenitors) have an almost total absence of brown dwarf companions within 5 AU !!

15 Figure from Grether & Lineweaver (2006) The Brown Dwarf Desert

16 Conclusions & future work:  Close binary (post-CE) PNe have a distinct trend in SB-r space, shared by optically-thin, low mass, high-excitation PNe.  Post-CE PNe have low ionized masses and distinctive filled- centre, bipolar or toroidal morphologies.  Post-CE PNe comprise a minority of PNe. Should they be called ‘true PNe’?  Need to continue search for close-binary nuclei via time- series photometry and RV monitoring  Need deep BVRIJHK photometry of all CSPN in local volume- limited PN sample. Utilise UKIDSS, VHS data… SPITZER…  Single stars can do it !!