EXPANSION PARALLAX OF THE PLANETARY NEBULA IC 418

Journal Article · Wed Jul 15 04:00:00 EDT 2009 · Astronomical Journal (New York, N.Y. Online)

DOI:https://doi.org/10.1088/0004-6256/138/1/46; COUNTRY OF INPUT: INTERNATIONAL ATOMIC ENERGY AGENCY (IAEA)· OSTI ID:21255708

Guzman, Lizette; Loinard, Laurent; Gomez, Yolanda ^[1]; Morisset, Christophe ^[2]

---

1. Centro de RadioastronomIa y AstrofIsica, Universidad Nacional Autonoma de Mexico, 58089 Morelia, Michoacan (Mexico)
2. Instituto de AstronomIa, Universidad Nacional Autonoma de Mexico, 04510 Mexico, D.F. (Mexico)

In this paper, we present radio continuum observations of the planetary nebula IC 418 obtained at two epochs separated by more than 20 years. These data allow us to show that the angular expansion rate of the ionization front in IC 418 is 5.8 {+-} 1.5 mas yr{sup -1}. If the expansion velocity of the ionization front is equal to the expansion velocity of the gas along the line of sight as measured by optical spectroscopy, then the distance to IC 418 must be 1.1 {+-} 0.3 kpc. Recent theoretical predictions appropriate for the case of IC 418, however, suggest that the ionization front may be expanding about 20% faster than the material. Under this assumption, the distance to IC 418 would increase to 1.3 {+-} 0.4 kpc.

• OSTI ID: 21255708
• Journal Information: Astronomical Journal (New York, N.Y. Online), Journal Name: Astronomical Journal (New York, N.Y. Online) Journal Issue: 1 Vol. 138; ISSN 1538-3881
• Country of Publication: United States
• Language: English

Related Subjects

79 ASTRONOMY AND ASTROPHYSICS
99 GENERAL AND MISCELLANEOUS
DISTANCE
EXPANSION
IONIZATION
PLANETARY NEBULAE
SPECTROSCOPY
STARS
VELOCITY