Sirius from Nashville

Sirius A

"Normal Star"

Sirius B

White Dwarf

Closest White Dwarf

Mroz et. al (2016) Image: (J. Skowron, K. Ulaczyk / Warsaw University Observatory)

Variability Search

Vera C. Rubin Observatory

20 TB per day
~40 billion catalog objects
Observe the entire southern night sky every three nights.

Transiting Exoplanet Survey Satellite TESS

Astronomical Surveys

Unsupervised Time Series Classification

Extract Time Series Features

Cluster Time Series

Time-series everywhere

Unsupervised Time-Series Classification

Searching for Exotic Binaries using their light-curves?

Feature Selection:
- Mean, Max, Min, ...
Clustering Methods:
- Affinity Propagation algorithm
- K-means
Distance Metric:
- Time Warp Edit Distance
- Dynamic Time Warping

Extra

NASA

Stellar Remants

White Dwarfs

Mass ~ 1 M☉

Radius ~ 1 R🜨

TESS Cadence and Coverage

Primary mission:
- 2-min selected targets
- 30-min full-frame images (FFI).
Extended:
- 20 sec selected targets
- 10-min FFI
Second extended mission
- 200-second FFI

A Binary White Dwarf

Accreting White Dwarf Binaries

Caltech

Semi-detached systems

Cataclysmic Variables

AM CVn

"Normal" Star
P_orb ~ 80 min - 10 hours
>1000 in the galactic field
Predicted large # in old Star Clusters

White Dwarf/Helium Star
P_orb ~ 5 - 70 min
Poorly understood Outburst
Type Ia SN and GW Sources
~70 in the galactic field

Caltech

Mark A. Garlick

Hydrogen-rich "normal" Star

White Dwarf

Gaia:

Mapping the Milky Way

Gaia:

Mapping the Milky Way

Big Data in Astronomy

Astrophysics and Big Data: Challenges, Methods, and Tools. DOI: 10.1017/S1743921316012813

Unsupervised Time-Series Classification

> 1200 Time-Series Features

Unsupervised Time-Series Classification

Searching for Exotic Binaries using their light-curves?

JD - 2458636

Szkody et. al (2020)

Magnitude

AM Canum Venaticorum AM CVn

White dwarf + White dwarf
White dwarf + He Star
Orbital Period: 5-70 minutes
Rare: 70 Galactic field

Caltech