2.3. Distance to LMC
The present status of the LMC distance is given in TABLE 4. The most traditional paths to the LMC distance follow the ladder shown in the upper half of TABLE 2. The Hipparcos satellite can measure a parallax down to 2 milli arcsec (mas), corresponding to a distance of 500 pc (ESA 1997). It was a reasonable expectation that one could obtain the geometric distance to the Pleiades cluster, circumventing the main sequence fitting from nearby parallax stars to the Pleiades and thus securing the Galactic distance scale. Hipparcos observations have also opened a number of novel methods that can be used to estimate the distance to LMC. This and related activities, however, have actually brought confusions, rather than securing the distance scale within the MW. We discuss several issues in order.
Method | Ref | Distance moduli |
Cepheid PL | Feast & Catchpole 1997 | 18.70 ± 0.10 |
Paturel et al. 1997 | 18.7 | |
Madore & Freedman 1998 | 18.57 ± 0.11 | |
Luri et al. 1998 | 18.29 ± 0.17 | |
Luri et al. 1998 | 18.21 ± 0.20 | |
(traditional) w/ new Pleiades | 18.26 | |
RR Lyrae (stat. para) | Fernley et al. 1998 | 18.31 ± 0.10 |
Luri et al. 1998 | 18.37 ± 0.23 | |
Udalski 1998 / Gould et al. 1998 | 18.09 ± 0.16 | |
RR Lyrae (subdwarf) | Reid 1997 | 18.65 |
Gratton et al. 1997 | 18.60 ± 0.07 | |
Mira | van Leeuwen et al. 1997 | 18.54 ± 0.18 |
Whitelock et al. 1997 | 18.60 ± 0.18 | |
Red clump | Udalski et al. 1998a | 18.08 ± 0.15 |
Stanek et al. 1998 | 18.07 ± 0.04 | |
Cole 1998 | 18.36 ± 0.17 | |
Eclipsing binaries | Guinan et al. 1998 | 18.30 ± 0.07 |
(Udalski et al. 1998b) | 18.19 ± 0.13(?) | |
SN 1987A Ring echo | Gould & Uza 1998 | < 18.37 ± 0.04 |
Sonneborn et al. 1997 | 18.43 ± 0.10 | |
Panagia et al. 1997 | 18.58 ± 0.03 | |
Lundqvist & Sonneborn 1997 | 18.67 ± 0.08 | |
Cepheid PL | Sekiguchi & Fukugita 1998 | 18.10-18.60 |
Sandage et al. 1999 | 18.57±0.05 | |
Cepheid PL (BW method) | Gieren et al. 1998 | 18.49 ± 0.05 |