Gamma Doradus variables are variable stars which display variations in luminosity due to non-radial pulsations of their surface. The stars are typically young, early F or late A type main sequence stars, and typical brightness fluctuations are 0.1 magnitudes with periods on the order of one day. This class of variable stars is relatively new, having been first characterized in the second half of the 1990s, and details on the underlying physical cause of the variations remains under investigation.
The star 9 Aurigae was first noticed to be variable in 1990. However, none of the currently-accepted explanations were adequate: it pulsated too slowly and was outside of the Delta Scuti instability strip, and there was no evidence for any eclipsing material, although Gamma Doradus and HD 96008 were noted to be similar. These three stars, as well as HD 224638, were soon hypothesized to belong to a new class of variable stars in which variability was produced by g-mode pulsations rather than the p-mode pulsations of Delta Scuti variables. HD 224945 and HD 164615 were noticed to be similar as well, while HD 96008 was ruled out on the basis of its more regular period. Eclipses and starspots were soon ruled out as the cause of the Gamma Doradus' variability, and the variability of 9 Aurigae was confirmed to be caused by g-mode pulsations a year later, thus confirming the stars as the prototypes of a new class of variable stars. Over ten more candidates were quickly found, and the discoverers dubbed the group the Gamma Doradus stars, after the brightest member and the first member found to be variable.
List Designation (name)ConstellationDiscoveryMaximum Apparent magnitude (mV)Minimum Apparent magnitude (mV)Period (days)Spectral classComment HD 8801 A(V529 And) Andromeda Henry & Fekel (2005) 6m.48(Hipparcos) 6m.51(Hipparcos) 0.40331 A7Vm First discovered hybrid Gamma Doradus/Delta Scuti variable V872 Ara Ara Aerts et al. (1998) 6m.37(Hipparcos) 6m.39(Hipparcos) 0.4266 A9V 9 Aur A Auriga Krisciunas (1993) 4m.93 5m.50 1.2582 F2V One of the original stars classified 17 CVn Canes Venatici Henry et al. (2011) 5m.91 0.8862 F0:V Spectroscopic binary; unclear which component is variable HD 108100(DD CVn) Canes Venatici Breger et al. (1996) 7m.15 0.7541 F2V V350 CMa A Canis Major Eyer & Aerts (2000) 6m.18 6m.27 0.775010.959 F2V Has two distinct periods V1026 Cen Centaurus Aerts et al. (1998) 9m.33(Hipparcos) 9m.38(Hipparcos) 1.1857 A3:m HD 17163 Cetus Henry et al. (2011) 6m.04 0.42351 F1V HD 14940(EP Cet) Cetus Aerts et al. (1998) 6m.74 6m.77 0.5004 F0IV/V 43 Cyg Cygnus Henry et al. (2005) 5m.75(Hipparcos) 5m.84(Hipparcos) 0.79955 F0V γ Dor Dorado Krisciunas (1993) 4m.23 4m.27 0.7570 F1V One of the original stars classified 8 Dra Draco Aerts et al. (1998) 5m.26(Hipparcos) 5m.34(Hipparcos) 0.42450 F1VmA7(n) DI Gru Grus Aerts et al. (1998) 8m.68 8m.76 0.8668 F3IV V1325 Her Hercules Kaye et al. (1998) 6m.38 0.4210 F0V 80 Leo Leo Henry & Fekel (2002) 6m.34 6m.37 0.45286 F3IV HD 40745(AC Lep) Lepus Aerts et al. (1998) 6m.28(Hipparcos) 6m.30(Hipparcos) 0.82427 F2IV HD 69682 Lynx Henry et al. (2011) 6m.50 0.53189 A9V DO Lyn Lynx Kaye et al. (1999) 7m.17 0.62447 F0V HD 50747 Monoceros Dolez et al. (2009) 5m.45 4.8650.956 A4IV Triple star; unknown which component is variable HD 49434 Monoceros Bruntt et al. (2002) 5m.75 0.57644 F1V Hybrid Gamma Doradus/Delta Scuti variable HD 41547 A Monoceros Henry et al. (2007) 5m.87 0.81123 F4V α Oph(Rasalhague) Ophiuchus Monnier et al. (2010) 2m.08 0.5850 A5IV Hybrid Gamma Doradus/Delta Scuti variable 73 Oph A Ophiuchus Fekel & Henry (2003) 6m.11 (B) 0.61439 F0V+G1V HD 164615(V2118 Oph) Ophiuchus Mantegazza et al. (1994) 7m.02 7m.09 0.8117 F2IV One of the original stars classified V2502 Oph Ophiuchus Aerts et al. (1998) 6m.57 6m.67 1.307 F2V HD 38309 Aa Orion Henry et al. (2011) 6m.09 0.37703 F0III:n NZ Peg Pegasus Henry et al. (2001) 5m.83(Hipparcos) 5m.86(Hipparcos) 0.41113 F2V HR 8799(V342 Peg) Pegasus Rodriguez & Zerbi (1995) 6m.00(Hipparcos) 6m.06(Hipparcos) 0.5053 A5V Lambda Boötis star and Vega-like star V372 Peg Pegasus Kaye et al. (1998) 6m.53 (B) 2.594821 F3V 39 Peg Pegasus Henry et al. (2005) 6m.43 6m.53 0.75574 F1V HD 224638(BT Psc) Pisces Krisciunas (1993) 7m.8 (B) 1.2323 F0V One of the original stars classified HD 224945(BU Psc) Pisces Mantegazza et al. (1994) 6m.93 0.5432 A9V One of the original stars classified QW Pup Puppis Poretti et al. (1997) 4m.47 4m.50 0.9584 F0IV/V ι TrA A Triangulum Australe Aerts et al. (1998) 5m.30(Hipparcos) 5m.42(Hipparcos) 1.4556 F4IV EE Tuc Tucana Aerts et al. (1998) 6m.72(Hipparcos) 6m.82(Hipparcos) 0.6935 F2IV V349 Tel Telescopium Aerts et al. (1998) 7m.60(Hipparcos) 7m.73(Hipparcos) 0.6953 F0V KO UMa Ursa Major Kaye et al. (1999) 7m.18 0.7691 F2V UY UMi Ursa Minor Aerts et al. (1998) 6m.30(Hipparcos) 6m.38(Hipparcos) 0.7237 F2V VX UMi Ursa Minor Henry et al. (2001) 6m.48 (B) 0.34510 A9V ε1 Lyr B Lyrae Peretto I., Lora S., Peretto G., Furlato G., Barbieri M. - MarSEC (2022)Peretto I., Lora S., Peretto G., Furlato G., Barbieri M. - MarSEC (2022) - https://www.aavso.org/vsx/index.php?view=detail.top&oid=2227434 6m.00 V (0.032) TESS 0.415 F0V
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