Study of Cepheid Variables as a Joint Near IR Spectroscopy Project Thomas C. Smith (Dark Ridge Observatory) Kenneth E. Kissell (Kissell Consultants)

Briefing Outline A brief history of spectroscopy of pulsating variables The present knowledge of pulsating variables Earlier Work Present Activities Future Work How You Can Help Q & A Thomas C. Smith (Dark Ridge Observatory) Kenneth E. Kissell (Kissell Consultants)

A brief history of spectroscopy of pulsating variables cont. The H-R Diagram - Refresher Thomas C. Smith (Dark Ridge Observatory) Kenneth E. Kissell (Kissell Consultants)

A brief history of spectroscopy of pulsating variables cont. Early Oxygen I Studies a)ε AurIa b)α LeoIb c)ζ LeoIII d)γ VirV ApJ, 111, 1, 1-10 (1950) Thomas C. Smith (Dark Ridge Observatory) Kenneth E. Kissell (Kissell Consultants)

A brief history of spectroscopy of pulsating variables cont. Partially Resolved O I Triplet in a Supergiant Ia Star Thomas C. Smith (Dark Ridge Observatory) Kenneth E. Kissell (Kissell Consultants)

A brief history of spectroscopy of pulsating variables Variables defined mostly from brightness Cycles. Pulsating variables cycle also in temperature / spectral type. An O I triplet feature noted by Merrill (1934) and Keenan and Hynek (1950) as unusually strong and dependent on temp/spectral type and luminosity class. Cepheids and RR Lyrae are in the zones of interest. Keenan suggested study of O I triplet (λ ) in testing of S-1 image tubes in Osmer and Parsons explore detection of A-F supergiants and Cepheids in nearby galaxies with λ7774 features ( ). Thomas C. Smith (Dark Ridge Observatory) Kenneth E. Kissell (Kissell Consultants)

A brief history of spectroscopy of pulsating variables (cont.) O I Luminosity Effects - Epoch (1950) W Thomas C. Smith (Dark Ridge Observatory) Kenneth E. Kissell (Kissell Consultants)

A brief history of spectroscopy of pulsating variables (cont.) Early 1N film and S-1 image tube data (1960s)

A brief history of spectroscopy of pulsating variables (cont.) O I Energy Levels Producing λ7774 Triplet Thomas C. Smith (Dark Ridge Observatory) Kenneth E. Kissell (Kissell Consultants)

A brief history of spectroscopy of pulsating variables (cont.) Cosmological Occurrence of Pulsation Instability Zones Thomas C. Smith (Dark Ridge Observatory) Kenneth E. Kissell (Kissell Consultants)

A brief history of spectroscopy of pulsating variables (cont.) Cepheid and RR Lyrae Pulsation Zones Thomas C. Smith (Dark Ridge Observatory) Kenneth E. Kissell (Kissell Consultants)

A brief history of spectroscopy of pulsating variables (cont.) Changes of the Oxygen Triplet Vs. Temperature/Spectral Type Thomas C. Smith (Dark Ridge Observatory) Kenneth E. Kissell (Kissell Consultants)

The present knowledge of pulsating variables Pulsation parameters Brightness Vs. phase Temperature Vs. phase Radial velocity Vs. phase Stellar radius Vs. phase Yet-to-be established parameters O I Triplet strength Vs. phase Spectral-type Vs. phase Thomas C. Smith (Dark Ridge Observatory) Kenneth E. Kissell (Kissell Consultants)

Earlier Work Thomas C. Smith (Dark Ridge Observatory) Kenneth E. Kissell (Kissell Consultants)

Present Activities 1960 – 1980 Film and Image Tube work required use of 1.5 – 3.5 meter telescopes to exploit the λ7774 feature. This required good justifications for durations of telescope time needed. 21 st century – CCD detectors – most sensitive of these wavelengths will allow use of advanced amateur facilities – Began augmentations of Dark Ridge Observatory equipped with an SBIG SGS spectrograph for detailed study of bright Cepheids – Initial spectra collected at Dark Ridge Observatory, California site, prior to relocation to New Mexico. Thomas C. Smith (Dark Ridge Observatory) Kenneth E. Kissell (Kissell Consultants)

Present Activities (Cont.) Luminosity Effects Using Different Measures W Thomas C. Smith (Dark Ridge Observatory) Kenneth E. Kissell (Kissell Consultants)

Present Activities (Cont.) Current: initial complications are being worked to resolve best resolution and wavelength calibration issues through 2008: Seek to define temperature/feature strength trajectories on HR diagram. Seek to add O I Triplet feature-strength plot (W versus phase) to existing Cepheid pulsation plots. Thomas C. Smith (Dark Ridge Observatory) Kenneth E. Kissell (Kissell Consultants)

Present Activities (Cont.) Early SGS Activation/Testing Thomas C. Smith (Dark Ridge Observatory) Kenneth E. Kissell (Kissell Consultants)

Future Work (Part 1) Luminosity Effects: Standard + Variables  Cep T Mon  Aql ζ Gem FF Aql Thomas C. Smith (Dark Ridge Observatory) Kenneth E. Kissell (Kissell Consultants)

Future Work (Part 2) Enhanced Cepheid pulsation plots O I Eq. W Thomas C. Smith (Dark Ridge Observatory) Kenneth E. Kissell (Kissell Consultants)

Future Work (Part 3) O I Triplet Velocity Vs. Photosphere Velocity A new challenge that must be explored. Should permit atmospheric pulsation models to identify the height in the stellar atmosphere of the Oxygen that is producing the triplet. It is unknown if amateur equipment and capabilities are capable of providing the required data. This requires the ability to measure the Doppler shift of the O I Triplet. Thomas C. Smith (Dark Ridge Observatory) Kenneth E. Kissell (Kissell Consultants)

Dark Ridge Observatory (DRO) Thomas C. Smith (Dark Ridge Observatory) Kenneth E. Kissell (Kissell Consultants)

DRO Cont. Thomas C. Smith (Dark Ridge Observatory) Kenneth E. Kissell (Kissell Consultants)

DRO Cont. Thomas C. Smith (Dark Ridge Observatory) Kenneth E. Kissell (Kissell Consultants)

How You Can Help Contribute spectral observations if equipped with high-resolution grating system (  Cephei and others) Monitor V, Rc, Ic photometry to assure the zero point of the phase. Contribute spectral observations at lower resolutions along with standard star spectra to determine spectral-types during the cycle. Thomas C. Smith (Dark Ridge Observatory) Kenneth E. Kissell (Kissell Consultants)

Target List TABLE I. Cepheid Characteristics for Candidate Program Stars Magnitude TABLE I. Cepheid Characteristics for Candidate Program Stars Name Right Ascension Declination Magnitude Epoch Period Spectral Type h m s ° ‘ “ max min ( ) d ======= ============= =========== ========= ========== ====== ============= T Mon F7Iab-KIIab RT Aur F4Ib-G1I  Gem F7Ib-G3Ib-G1Ib X Sgr F5-G2II W Sgr F4-G2Ib Y Sgr F5-G0Ib -II FF Aql F5Ia-F8Ia  Aql F6Ib-G4Ib S Sge F6Ib-G5Ib X Cyg F7Ib-G8Ib T Vul F5Ib-G0Ib  Cep F5Ib-G1Ib ======= ============= ========== ========= ========== ====== ============= RR Lyr A5.0-F7.0 Thomas C. Smith (Dark Ridge Observatory) Kenneth E. Kissell (Kissell Consultants)

Q & A Don’t Be Shy! For information regarding how you can assist in this rediscovered project: Thomas C. Smith (Dark Ridge Observatory) Kenneth E. Kissell (Kissell Consultants)