Frosty Leo Nebula

Protoplanetary nebula


caption= 2003 Hubble Advanced Camera for Surveys HRC
name = Frosty Leo Nebula
epoch = J2000
ra = RA|09|39|53.96Harv|SIMBAD|2007]
dec = DEC|+11|58|52.4
dist_ly = 3.0 kly (920 pc)Harv|Davis|Smith|Gledhill|Varricatt|2005]
appmag_v = 11Harv|Beuzit|Thebault|Perrin|Rouan|1994]
size_v = 25″
constellation = Leo
radius_ly = 0.18 lyRef_label|A|a|none
absmag_v = 1.2Ref_label|B|b|none
notes = Crystalline Ice, Point
Reflection Symmetry
names = IRAS 09371+1212The Frosty Leo Nebula is a protoplanetary nebula (PPN) located roughly at 3,000 light-years Harv|Davis|Smith|Gledhill|Varricatt|2005 away from Earth in the direction of the constellation Leo. It is a spectralHarv|Omont|Forveille|Moseley|Glaccum|1990] bipolar nebula. Its central star is of optical spectral type K7II. It is unusual in that it has an extremely deep absorption feature at 3.1µm and is unusually located at more than 900 pc above the plane of our galaxy.Harv|Bourke|Hyland|Robinson|Luhman|2000 Further, as of 1990, it has the only known PPN circumstellar outflow in which crystalline ice dominates the long-wavelength emission spectrum and the only known PPN with point-reflection-symmetric deviations from axial symmetry.

Characteristics

The Frosty Leo Nebula has two lobes that are separated by 2″ between which is an almost edge-on dust ring. It also has two relatively faint but prominent compact nebulosities, or ansae, separated by ~23″ along the polar axis of the PPN. The PPN as a whole has an hourglass like shape. It has an inclination angle of 15° relative to the plane of the sky. Its molecular envelope is expanding at a rate of ~25 km/s.

Observation history

This PPN was first noticed in the IRAS survey due to its exceptionally cold IRAS color temperatures.Harv|Morris|Reipurth|1990] It also has a uniquely sharp maximum at 60-μM.Harv|Forveille|Morris|Omont|Likkel|1987]

Point symmetry

It is the first bipolar PPN known to have point reflection symmetry (all others being axially symmetric). Point symmetry is a fairly common trait of planetary nebulae as found in NGC 2022, NGC 2371-2, NGC 6309, Cat's Eye Nebula, NGC 6563, Dumbbell Nebula, Saturn Nebula, A24, and Hb5. Harvnb|Morris|Reipurth|1990 postulate that point symmetry is either due to the bipolar outflow being directed by a precessing disc or a precessing common envelope binary.

Naming

Harvnb|Forveille|Morris|Omont|Likkel|1987 dubbed IRAS 09371+1212 as the "Frosty Leo Nebula" because of their interpretation of the object's extremely unusual far infrared spectrum that water is largely depleted in its gaseous state by ice condensation into grains and for its location in the Leo constellation. Their interpretation was subsequently verified in 1988 by three independent papers. Harvnb|Omont|Forveille|Moseley|Glaccum|1990 further observed in the band between 35 to 65 μM that very cold (<50 K) silicate dust grains, abundantly coated with crystalline ice, are responsible for the 60-μM excess.

Notes

1. Note_label|A|a|none3.0 kly &times; sin( 25&Prime; / 2 ) = 0.18 ly. radius
2. Note_label|B|b|none11 apparent magnitude - 5 * (log₁₀(920 pc distance) - 1) = 1.2 absolute magnitude

References

* Harvard reference
Surname1 = Beuzit
Given1 = J.-L.
Surname2 = Thebault
Given2 = P.
Surname3 = Perrin
Given3 = G.
Surname4 = Rouan
Given4 = D.
Title = Adaptive optics imaging of the Frosty Leo nebula
Journal = Astronomy and Astrophysics (ISSN 0004-6361)
Year = 1994
Date = November 1994
Volume = 291
Issue = 1
Pages = L1-L4
URL = http://adsabs.harvard.edu/abs/1994A&A...291L...1B
* Harvard reference
Surname1 = Bourke
Given1 = Tyler
Surname2 = Hyland
Given2 = A. R.
Surname3 = Robinson
Given3 = Garry
Surname4 = Luhman
Given4 = Kevin
Title = The Evolutionary Status of the Frosty Leo Nebula
Journal = Asymmetrical Planetary Nebulae II: From Origins to Microstructures, ASP Conference Series. Edited by J. H. Kastner, N. Soker, and S. Rappaport. ISBN 1-58381-026-9
Year = 2000
Volume = 199
Issue = 1
Pages = 171
URL = http://adsabs.harvard.edu/cgi-bin/nph-bib_query?bibcode=2000ASPC..199..171B
* Harvard reference
Surname1 = Davis
Given1 = C. J.
Surname2 = Smith
Given2 = M. D.
Surname3 = Gledhill
Given3 = T. M.
Surname4 = Varricatt
Given4 = W. P.
Title = Near-infrared echelle spectroscopy of protoplanetary nebulae: probing the fast wind in H₂
Journal = Monthly Notices of the Royal Astronomical Society
Year = 2005
Volume = 360
Issue = 1
Pages = 104-118
URL = http://adsabs.harvard.edu/cgi-bin/nph-bib_query?bibcode=2005MNRAS.360..104D
* Harvard reference
Surname1 = Forveille
Given1 = T.
Surname2 = Morris
Given2 = M.
Surname3 = Omont
Given3 = A.
Surname4 = Likkel
Given4 = L.
Title = IRAS 09371+1212 - an icy evolved, mass-losing star with a unique IR spectrum
Journal = Astronomy and Astrophysics (ISSN 0004-6361)
Year = 1987
Date = April 1987
Volume = 176
Issue = 1
Pages = L13-L16
URL = http://adsabs.harvard.edu/abs/1987A%26A...176L..13F
* Harvard reference
Surname1 = Morris
Given1 = Mark
Surname2 = Reipurth
Given2 = Bo
Title = The optical form of the bipolar preplanetary nebula IRAS 09371 + 1212
Journal = Astronomical Society of the Pacific, Publications (ISSN 0004-6280)
Year = 1990
Date = April 1990
Volume = 102
Issue =
Pages = 446-453
URL = http://adsabs.harvard.edu/abs/1990PASP..102..446M

* Harvard reference
Surname1 = Omont
Given1 = A.
Surname2 = Forveille
Given2 = T.
Surname3 = Moseley
Given3 = S. H.
Surname4 = Glaccum
Given4 = W. J.
Surname5 = Harvey
Given5 = P. M.
Surname6 = Likkel
Given6 = L.
Surname7 = Loewenstein
Given7 = R. F.
Surname8 = Lisse
Given8 = C. M.
Title = Observations of 40-70 micron bands of ice in IRAS 09371 + 1212 and other stars
Journal = Astrophysical Journal, Part 2 - Letters (ISSN 0004-637X)
Year = 1990
Date = May 20 1990
Volume = 355
Issue =
Pages = L27-L30
URL = http://adsabs.harvard.edu/abs/1990ApJ...355L..27O
* Harvard reference
Surname1 = SIMBAD
Title = Results for Frosty Leo Nebula
Authorlink = SIMBAD
Journal =
Year = 2007
Date = January 7 2007
Publisher = SIMBAD, Centre de Données Astronomiques de Strasbourg
URL = http://simbad.u-strasbg.fr/simbad/sim-id?protocol=html&Ident=Frosty+Leo+Nebula

External links

* [http://www.ifa.hawaii.edu/ao/images/proto/fleo.html Image of Frosty Leo Nebula.]