New young planetary nebulae in IPHAS

Aims. We search for very small-diameter galactic planetary nebulae (PNe) representing the earliest phases of PN evolution. The IPHAS catalogue of Hα-emitting stars provides a useful basis for this study since all sources present in this catalogue must be of small angular diameter. Methods. The PN candidates are selected based on their location in two colour−colour diagrams: IPHAS (r � − Hα )v s. (r � − i � ), and 2MASS (J − H )v s. (H − Ks). Spectroscopic follow-up was carried out on a sample of candidates to confirm their nature. Results. We present a total of 83 PN candidates. We were able to obtain spectra or find the classification from the literature for 35 candidates. Five of these objects are likely to be new PNe, including one large bipolar PN discovered serendipitously close to an emission-line star. PN distances deduced from extinction-distance relations based on IPHAS field-star photometry are presented for the first time. These yield distance estimates for our objects in the range 2 kpc and 6 kpc. From the data in hand, we conclude that four of the discovered objects are probably young PNe.

[1]  Radio continuum properties of young planetary nebulae , 2008, 0807.3684.

[2]  M. Dopita,et al.  The evolutionary sequence of planetary nebulae , 1990 .

[3]  Franz Kerschbaum,et al.  Why galaxies care about AGB stars : their importance as actors and probes : proceedings of an international conference held at University Campus, Vienna, 7-11 August 2006 , 2007 .

[4]  M. Livio,et al.  Hen 2-104: A close-up look at the Southern Crab ⋆ , 2008, 0803.0448.

[5]  A. Kawamura,et al.  A13CO Survey of Molecular Clouds in Gemini and Auriga , 1998 .

[6]  J. Cantó.  Herbig-Haro Objects: Recent Observational and Theoretical Developments , 1981 .

[7]  C. Beichman,et al.  A search for T Tauri stars in high-latitude molecular clouds. 2: The IRAS Faint Source Survey catalog , 1995 .

[8]  T. Ray,et al.  A HST study of the environment of the Herbig Ae/Be star LkHα 233 and its bipolar jet , 2008, 0804.0257.

[9]  R. Sahai,et al.  Echelle Long-Slit Optical Spectroscopy of Evolved Stars , 2008, 0806.4474.

[10]  Isaac Newton Group of Telescopes,et al.  The IPHAS catalogue of Hα emission‐line sources in the northern Galactic plane , 2007, 0712.0988.

[11]  R. Corradi,et al.  IPHAS and the symbiotic stars. I. Selection method and first discoveries , 2007, 0712.2391.

[12]  R. Corradi.  He 2–25, Th 2–B, 19W32: further links between bipolar planetary nebulae and symbiotic stars? , 1995 .

[13]  A. Mampaso,et al.  Shocked excitation in the bipolar nebula CRL 618 , 1990 .

[14]  R. Davies,et al.  Astronomical Society of the Pacific Conference Series , 2010 .

[15]  E. Mannery,et al.  Emission line spectra of Herbig-Haro objects , 1981 .

[16]  S. Drake,et al.  The emission-line spectrum from a slab of hydrogen at moderate to high densities. , 1980 .

[17]  A. Acker,et al.  MASH-II: more planetary nebulae from the AAO/UKST Hα survey , 2007, 0711.2923.

[18]  S. Wolf,et al.  A silicate disk in the heart of the Ant , 2007, 0710.0499.

[19]  J. Mathis,et al.  The relationship between infrared, optical, and ultraviolet extinction , 1989 .

[20]  L. F. Miranda,et al.  The identification of PM 1-322 as a new young high-density planetary nebulae , 2005 .

[21]  High spatial resolution Galactic 3D extinction mapping with IPHAS , 2008, 0810.2547.

[22]  R. D. Oudmaijer,et al.  The population of the Galactic plane as seen by MSX , 2002 .

[23]  Janet E. Drew,et al.  Initial data release from the INT Photometric Hα Survey of the Northern Galactic Plane (IPHAS) , 2007, 0712.0384.

[24]  L. Aller,et al.  Chemical compositions of planetary nebulae. , 1983 .

[25]  S. R. Pottasch,et al.  A spectroscopic atlas of post-AGB stars and planetary nebulae selected from the IRAS point source catalogue , 2006, astro-ph/0608080.

[26]  From Red Giants to Planetary Nebulae , 1982 .

[27]  M. Morris,et al.  Preplanetary Nebulae: A Hubble Space Telescope Imaging Survey and a New Morphological Classification System , 2007, 0707.4662.

[28]  G. Mellema,et al.  Line ratios from shocked cloudlets in planetary nebulae , 2008 .

[29]  Y. Fukui,et al.  Molecular Clouds in Cepheus and Cassiopeia , 1997 .

[30]  B. T. Lynds.  Catalogue of Dark Nebulae. , 1962 .

[31]  P. Hartigan,et al.  Radiative Bow Shock Models of Herbig-Haro Objects , 1987 .

[32]  J. P. Phillips.  SEARCHING FOR BALMER SELF-ABSORPTION IN PLANETARY NEBULAE , 2006 .

[33]  R. Corradi,et al.  The "Principes de Asturias" nebula: A new quadrupolar planetary nebula from the IPHAS survey , 2006, astro-ph/0608108.

[34]  U. Munari,et al.  A catalogue of symbiotic stars , 2000 .

[35]  M. Irwin,et al.  Early‐A stars from IPHAS, and their distribution in and around the Cyg OB2 association , 2008, 0802.3868.

[36]  Q. Parker,et al.  Two new evolved bipolar planetary nebulae in the solar neighbourhood , 2006 .

[37]  J. Köppen,et al.  The Macquarie/AAO/Strasbourg Hα Planetary Nebula Catalogue: MASH , 2006 .

[38]  R. Corradi,et al.  Evidence for binarity in the bipolar planetary nebulae A 79 , He 2-428 and M 1-91 , 2001, astro-ph/0109437.

[39]  R. Ortiz,et al.  Evolution from AGB to planetary nebula in the MSX survey , 2004 .