Manuel Pichardo Marcano (Texas Tech University)

Liliana Rivera Sandoval, Thomas J. Maccarone, Simone Scaringi

TACOS:

TESS AM CVn Outbursts Survey

AM Canum Venaticorum AM CVn

  • White dwarf + White dwarf

  • White dwarf + He Star

  • Orbital Period: 5-70 minutes

  • Rare: 70 Galactic field

Caltech

AM CVns

  •  Helium Rich and (some) known to go into outbursts

Kupfer et. al (2013)

Duffy et. al (2021)

Disk AM CVns

Luminosity

Period (min)

High state (high Ṁ)

  • Hot ionized disk

Outbursting System

~20

~10

~40-60 (?)

Low state (low Ṁ)

  • Cold stable disk

Caltech

  • Porb 20 to ~ 60 minutes (?)

  • Superoutburts (SO) and "Normal" outbursts (NO)

  • Disk instability model (DIM)

    •  Constant Mass transfer rate

    • Tidal-thermal disk instability model

      • SO: Superhumps (periodic brightness variation )

Outbursting Systems

Caltech

  • Porb 20 to ~ 60 minutes (?)

  • Superoutburts (SO) and "Normal" outbursts (NO)

  • Disk instability model (DIM)

    •  Constant Mass transfer rate

    • Tidal-thermal disk instability model

      • SO: Superhumps (periodic brightness variation )

Outbursting Systems

Place Constraints

Caltech

  • Porb 20 to ~ 60 minutes (?)

  • Superoutburts (SO) and "Normal" outbursts (NO)

  • Disk instability model (DIM)

    •  Constant Mass transfer rate

    • Tidal-thermal disk instability model

      • SO: Superhumps (periodic brightness variation )

Outbursting Systems

Better LC → Better Constraints

Place Constraints

Empirical Relationships

  1. Trec ∝ Porb7.35
  2. Tdur ∝ Porb4.54
  3. Δ mag ∝ Porb
  4. Ground-Based:
    1. PTF/CRTS
    2. ZTF
    3. LINEAR

Levitan et al. 2015

See also Duffy et al. 2021

Empirical Relationships

  1. Trec ∝ Porb7.35
  2. Tdur ∝ Porb4.54
  3. Δ mag ∝ Porb
  4. Ground-Based:
    1. PTF/CRTS
    2. ZTF
    3. LINEAR

Levitan et al. 2015

See also Duffy et al. 2021

Need detailed short-term variability

Empirical Relationships

  1. Trec ∝ Porb7.35
  2. Tdur ∝ Porb4.54
  3. Δ mag ∝ Porb
  4. Ground-Based:
    1. PTF/CRTS
    2. ZTF
    3. LINEAR

Levitan et al. 2015

See also Duffy et al. 2021

Better LC → Better Constraints

Transiting Exoplanet Survey Satellite (TESS)

Outbursts

Pichardo Marcano et al. (2021)

Type of Super Outbursts

Osaki et al. (2005)

High Mass Ratio

DIM

Cataclysmic Variables

  • Evolution Superhump

Pichardo Marcano et al. (2021)

ASASSN-14cc

Pichardo Marcano et al. (2021)

9–18 d

kato et al. (2015)

  • 2 Super Outbursts:
    • No precursor
    • Variable in length
      • Compare Kato+'15 and Duffy+'21
  • Superhump period
    • 10 minute cadence
  • Precursor
    • TESS (Duffy et al. 2021)
  • Echo Outbursts
  • DIM with Enhanced Mass Transfer  (e.g. Hameury & Lasota 2021)

PTF1 J0719+4858

Pichardo Marcano et al. (2021)

ZTF

TESS

Color Evolution

PTF1 J0719+4858

SS Cyg

Cataclysmic Variable

Hameury et al. (2020)

  • Similar to Dwarf Novae

    • Hameury et al. (2020)

  • Similar SDSS J1411+4812
    • Rivera Sandoval et al. (2021)
  • Compare to SDSS 1137/SDSS 0807
    • Rivera Sandoval et al. (2021)

Pichardo Marcano et al. (2021)

Color Evolution

PTF1 J0719+4858

SDSS J113732+405458

 Enhanced mass transfer

  • Similar to Dwarf Novae

    • Hameury et al. (2020)

  • Similar SDSS J1411+4812
    • Rivera Sandoval et al. (2021)
  • Compare to SDSS 1137/SDSS 0807
    • Rivera Sandoval et al. (2021)

Pichardo Marcano et al. (2021)

Rivera Sandoval et al. (2021)

  • Precursor
    • TESS (Duffy et al. 2021)
  • Echo Outbursts
  • DIM with Enhanced Mass Transfer  (e.g. Hameury & Lasota 2021)

SDSS J1043+5632

Pichardo Marcano et al. (2021)

ZTF

TESS

Type of Echo Outbursts

SDSS J1043+5632

PTF1 J0719+4858

  • WZ Sge like ?
    • Precursors
    • EMT (Hameury+'20)
    • Massive WD?
  • Compare to TCP J21040470+4631129
    • EMT (Hameury+'20)
  • Helium "SU UMa"
    • EMT+TTI (Kotko+'12)

SDSSJ1043+5632

  • Similar to Dwarf Novae:
    • Hameury et al. (2020)
    • Rivera Sandoval et al. (2021)

Color Evolution

Pichardo Marcano et al. (2021)

Long-term monitoring

Pichardo Marcano et al. (2021)

  • Orbital Periods:
    • 2-minute cadence
  • Limits on Recurrence Time
  • "Normal Outburts"

Gaia16all

Normal Outburts

PTF1 J2219+3135

V803 Cen

  • V803 Cen
    • "Cycle"
    • Low Ṁ?
  • Timing Normal Outbursts:
    • Permanent Superhumper?

Superoutburst duration vs Porb

Pichardo Marcano et al. (2021)

TACOS Summary

  • Precursors and "Normal" Outbursts:
    • Relatively Common
    • Short Duration (missed by ground-based)
  • Echo Outbursts:
    • Different morphology
    • Enhanced Mass Transfer
  • Superoutburst durations overestimated
  • Two new candidate orbital periods
  • Color Evolution

Other work with Accreting WDs

  • Follow-up eROSITA transient:

  • TESS time series analysis

    • Atel: Pichardo Marcano (2020)

    • Paper: Schwope, [...], Pichardo Marcano, et al. (2021)

Caltech

PTF1 J0719+4858:

  • Similar to Dwarf Novae:
    • Hameury et al. (2020)
    • Rivera Sandoval et al. (2021)

Color Evolution

Pichardo Marcano et al. (2021)

Accreting White Dwarf Binaries

Cataclysmic Variables

AM CVn

  • Main Sequence Star
  • Porb ~ 80 min - 10 hours
  • Outbursts:
    • 2-20 days
    • Disk instability model+ (DIM)
  • >1000 in the galactic field
  • Predicted large # in old Star Clusters
  • White Dwarf/Helium Star
  • Porb ~ 5 - 70 min
  • Outburts:
    • weeks?
    • DIM?
  • ~70 in the galactic field

Mark A. Garlick

Caltech

AM CVns

  •  Helium Rich and Know to go into outburts

Kupfer et. al (2013)

Duffy et. al (2021)

Normal Outbursts

V803 Cen

  • WZ Sge like ?
    • Precursors
    • EMT (Hameury+'20)
    • Massive WD?
  • Compare to TCP J21040470+4631129
    • EMT (Hameury+'20)
  • Helium "SU UMa"
    • EMT+TTI (Kotko+'12)

Caltech

  • Porb 20 to ~ 60 minutes (?)

  • Superoutburts (SO) and "Normal" outbursts (NO)

    • SO: Superhumps (periodic brightness variation )

  • Disk instability model (DIM)

    •  Constant Mass transfer rate

    • Tidal-thermal disk instability model

Outbursting Systems