# TESS Program G03178

Title: Photometric Variability Among Helium-Rich White Stars As An Indicator For The Presence Of Magnetic Fields

PI: Holberg, Jay - University Of Arizona

Type: SMALL

Summary: We propose TESS observations of a select set of cool DC (He-rich) and DQ (trace C) white dwarfs. The objective is to detect coherent photometric modulations due to white dwarf rotation. Such variations have been observed in hotter DA (H-rich) white dwarfs, where frozen-in magnetic spots produce azimuthal photospheric asymmetries. Due to the low temperatures and the lack of spectroscopic hydrogen, magnetic fields are hard to detect in DQ and DC stars. Detections of coherent modulations in DQ or DC stars would be strong evidence for the existence of magnetic fields. There is strong observational and theoretical evidence that white dwarf magnetic fields are the signature of binary merger events which would help account for the well-established lack of white dwarfs in binary systems.


# Sector 027 targets observed (2 min: 6, 20 s: 1)
201730948,303.1364,-59.9556,15.17,G03207;G03124;G03178;20SECONDTARGET
325341805,337.6489,-75.2672,15.7,G03207;G03124;G03178
325341811,337.6758,-75.2424,15.49,G03207;G03124;G03178
426018482,43.2004,-75.3777,16.23,G03207;G03178
300013123,107.2145,-67.1093,15.38,G03207;G03124;G03178
220476416,75.6804,-55.4446,16.11,G03207;G03124;G03178

# Sector 028 targets observed (2 min: 5, 20 s: 2)
53950266,328.7537,-27.843,15.81,G03207;G03124;G03178
140045537,329.4094,-51.011,14.24,G03174;G03207;G03124;G03178;20SECONDTARGET
426018482,43.2004,-75.3777,16.23,G03207;G03178
300013123,107.2145,-67.1093,15.38,G03207;G03124;G03178
306826966,121.7288,-66.3063,13.69,G03207;G03124;G03178;20SECONDTARGET

# Sector 029 targets observed (2 min: 5, 20 s: 2)
70743424,0.6681,-34.2321,14.56,G03207;G03124;G03178;20SECONDTARGET
426018482,43.2004,-75.3777,16.23,G03207;G03178
220476416,75.6804,-55.4446,16.11,G03207;G03124;G03178
300013123,107.2145,-67.1093,15.38,G03207;G03124;G03178
306826966,121.7288,-66.3063,13.69,G03207;G03124;G03178;20SECONDTARGET

# Sector 030 targets observed (2 min: 1, 20 s: 0)
220476416,75.6804,-55.4446,16.11,G03207;G03124;G03178

# Sector 031 targets observed (2 min: 4, 20 s: 1)
178937531,68.3926,-27.8903,16.05,G03207;G03178
220476416,75.6804,-55.4446,16.11,G03207;G03124;G03178
300013123,107.2145,-67.1093,15.38,G03207;G03124;G03178
306826966,121.7288,-66.3063,13.69,G03207;G03124;G03178;20SECONDTARGET

# Sector 032 targets observed (2 min: 7, 20 s: 2)
60878053,66.4733,12.1954,14.93,G03207;G03124;G03178
1168117,71.1219,-30.3622,15.97,G03207;G03124;G03178
178937531,68.3926,-27.8903,16.05,G03207;G03178
55997020,69.4489,-8.8286,13.32,G03207;G03124;G03178;20SECONDTARGET
220476416,75.6804,-55.4446,16.11,G03207;G03124;G03178
300013123,107.2145,-67.1093,15.38,G03207;G03124;G03178
306826966,121.7288,-66.3063,13.69,G03207;G03124;G03178;20SECONDTARGET

# Sector 033 targets observed (2 min: 3, 20 s: 0)
125019732,105.1737,-7.571,16.11,G03207;G03178
238164321,106.481,-50.8788,16.5,G03207;G03178
220476416,75.6804,-55.4446,16.11,G03207;G03124;G03178

# Sector 034 targets observed (2 min: 8, 20 s: 1)
323595796,136.3125,9.0727,16.62,G03207;G03178
816793,134.8047,-0.9793,15.54,G03207;G03178
220590402,117.562,7.1865,15.91,G03207;G03178
220590405,117.5652,7.1832,15.73,G03207;G03178
149744486,116.4082,-33.9211,15.58,G03207;G03178
238164321,106.481,-50.8788,16.5,G03207;G03178
300013123,107.2145,-67.1093,15.38,G03207;G03124;G03178
306826966,121.7289,-66.3063,13.69,G03207;G03124;G03178;20SECONDTARGET

# Sector 035 targets observed (2 min: 3, 20 s: 1)
238164321,106.481,-50.8788,16.5,G03207;G03178
300013123,107.2144,-67.1093,15.38,G03207;G03124;G03178
306826966,121.7289,-66.3063,13.69,G03207;G03124;G03178;20SECONDTARGET

# Sector 036 targets observed (2 min: 7, 20 s: 1)
179299789,159.7297,-20.6792,15.49,G03124;G03178
902107745,161.401,-19.1161,15.04,G03207;G03178
397418667,177.899,-27.5389,15.46,G03207;G03124;G03178
38086703,169.5596,-3.2335,15.26,G03207;G03124;G03178
306826966,121.7289,-66.3063,13.69,G03207;G03124;G03178;20SECONDTARGET
300013123,107.2144,-67.1093,15.38,G03207;G03124;G03178
220476416,75.6803,-55.4447,16.11,G03207;G03124;G03178

# Sector 037 targets observed (2 min: 4, 20 s: 2)
323485429,176.4659,-64.8436,11.3,G03207;G03178;20SECONDTARGET
306826966,121.7289,-66.3064,13.69,G03207;G03124;G03178;20SECONDTARGET
300013123,107.2144,-67.1093,15.38,G03207;G03124;G03178
220476416,75.6803,-55.4447,16.11,G03207;G03124;G03178

# Sector 038 targets observed (2 min: 4, 20 s: 2)
448023860,199.8654,-78.3933,15.51,G03207;G03124;G03178
323485429,176.4661,-64.8436,11.3,G03207;G03178;20SECONDTARGET
300013123,107.2144,-67.1093,15.38,G03207;G03124;G03178
306826966,121.7289,-66.3064,13.69,G03207;G03124;G03178;20SECONDTARGET

# Sector 039 targets observed (2 min: 6, 20 s: 1)
119091732,275.4973,-59.8656,15.96,G03124;G03178
1513408229,266.9035,-54.6011,19.34,G03178
448023860,199.8654,-78.3933,15.51,G03207;G03124;G03178
300013123,107.2144,-67.1093,15.38,G03207;G03124;G03178
306826966,121.729,-66.3064,13.69,G03207;G03124;G03178;20SECONDTARGET
220476416,75.6803,-55.4447,16.11,G03207;G03124;G03178