We performed a photometric and spectroscopic analysis of two RV Tauri stars GK Car and GZ Nor .
Both objects are surrounded by hot circumstellar dust .
Their pulsation periods , derived from ASAS photometric time series , have been used to derive their luminosities and distances via the PLC relation .
In addition , for both objects , GAIA distances are available .
The Gaia distances and luminosities are consistent with the values obtained from the PLC relationship .
GK Car is at distance of 4.5 \pm { 1.3 } kpc and has a luminosity of 1520 \pm { 840 } L _ { \odot } , while GZ Nor is at distance of 8.4 \pm { 2.3 } kpc and has a luminosity of 1240 \pm { 690 } L _ { \odot } .
Our abundance analysis reveals that both stars show depletion of refractory elements with [ Fe/H ] = - 1.3 and [ Zn/Ti ] = + 1.2 for GK Car and [ Fe/H ] = - 2.0 and [ Zn/Ti ] = + 0.8 for GZ Nor .
In the WISE colour-colour diagram , GK Car is located in the RV Tauri box as originally defined by [ ] and updated by [ ] , while GZ Nor is not .
Despite this , we argue that both objects are surrounded by a gravitationally bound disc .
As depletion is observed in binaries , we postulate that both stars are binaries as well .
RV Tauri stars are generally acknowledged to be post - AGB stars .
Recent studies show that they might be either indeed post - AGB or post - RGB objects depending on their luminosity .
For both objects , the derived luminosities are relatively low for post-AGB objects , however , the uncertainties are quite large .
We conclude that they could be either post-RGB or post-AGB objects .