Photometry and spectroscopy of variable stars with small telescopes. Vadim Burwitz (MPE) May 10, 2013 Small Telescope Workshop Istanbul

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1 Photometry and spectroscopy of variable stars with small telescopes Vadim Burwitz (MPE) May 10, 2013 Small Telescope Workshop Istanbul Photometry and spectroscopy of varaible stars, May 10, 2013

2 Overview Variable Stars What are they? Measurements Classification Variable stars: X-ray / optical connection Accreting white dwarfs The PIRATE Robotic Telescope Project Spectrographs for small telescopes: DADOS BACHES May 10, 2013 Photometry and Spectroscopy of Variable Stars with Small Telescopes VadimBurwitz(MPE)

3 What are variable stars? They are stars that show changes in brightness as seen from earth. The reason for brightness changes are manifold: Intrinsic: Pulsating evolutionary stage (physical properties) Eruptive Flares, Mass ejections Cataclysmic / Explosive Novae, Supernovae Extrinsic: Geometry Eclipses in binary systems Rotational effects May 10, 2013 Photometry and Spectroscopy of Variable Stars with Small Telescopes VadimBurwitz(MPE)

4 Measurements Photometric lightcurves give The periodspresent in the star: orbital, spin, pulsation The shape symmetry, eclipses, dips Optical spectra yield Spectral type / Luminosity class Absorption and emission lines Radial velocity shifts Changes in temperature Magnetic fields May 10, 2013 Photometry and Spectroscopy of Variable Stars with Small Telescopes VadimBurwitz(MPE)

5 The zoo of variable Stars o The zoo is full of many stars sorted into many categories o based on physical characteristics. o Measurable periods are in the range minutes to years. o Most of these variable stars can be observed with small telescopes. May 10, 2013 Photometry and Spectroscopy of Variable Stars with Small Telescopes Image source wikipedia VadimBurwitz(MPE)

6 Variable stars: X-ray / optical connection Types of optical observations to complement X-ray observations Follow-up observations (ROSAT, future erosita) post discovery: photometry / spectroscopy Preparatory observations (XMM, Chandra) trigger X-ray observations for objects with X-ray bright and faint states Contemporaneous multiwavelength observations (SWIFT, XMM, Chandra etc) during the X-ray observations May 10, 2013 Photometry and Spectroscopy of Variable Stars with Small Telescopes VadimBurwitz(MPE)

7 Accreting white dwarfs Types of accreting white dwarfs Magnetic and non-magnetic accretion White dwarfs at high accretion rates Supersoft X-ray Sources Novae in M31 May 10, 2013 Photometry and Spectroscopy of Variable Stars with Small Telescopes VadimBurwitz(MPE)

8 Types of accreting white dwarfs non-magnetic accretion = boundary layer accr. Magnetic and non-magnetic accretion magnetic accretion = funnel accretion Polars or AM Her stars Intermediate polars or DQ Her Stars May 10, 2013 Photometry and Spectroscopy of Variable Stars with Small Telescopes VadimBurwitz(MPE)

9 Boundary Layer Accretion Wind White Dwarf Accretion Disk Boundary Layer - X-rays Wind May 10, 2013 Photometry and Spectroscopy of Variable Stars with Small Telescopes VadimBurwitz(MPE)

10 May 10, 2013 Photometry and Spectroscopy of Variable Stars with Small Telescopes VadimBurwitz(MPE)

11 Types of accreting white dwarfs non-magnetic accretion = boundary layer accr. Magnetic and non-magnetic accretion magnetic accretion = funnel accretion Polars or AM Her stars Intermediate polars or DQ Her Stars May 10, 2013 Photometry and Spectroscopy of Variable Stars with Small Telescopes VadimBurwitz(MPE)

12 Magnetic cataclysmic variables (mcvs) Polars P orb = P (synchronous) spin No accretion disk B ~ MG Intermediate Polars P orb > P spin possible accretion disk B upto 20 MG May 10, 2013 Photometry and Spectroscopy of Variable Stars with Small Telescopes VadimBurwitz(MPE)

13 Overall spectrum of mcvs Optical White Dwarf UV Soft X-rays Hard X-rays Red Dwarf IR May 10, 2013 Photometry and Spectroscopy of Variable Stars with Small Telescopes VadimBurwitz(MPE)

14 Standard accretion scenario in mcvs Magneticfield-strength B = Million Gauss Magnetic field line cool supersonic accretion flow Magnetic field line Infrared Optical UV (cyklotronradiation) Soft X-rays UV (black-body radiation) T = Kelvin SHOCK stream of slow shock heated Matter Hard X-raysX (Bremsstrahlung) T = Million Kelvin White Dwarf Photosphere T = K Blobs of matter that release Energy below the surface May 10, 2013 Photometry and Spectroscopy of Variable Stars with Small Telescopes VadimBurwitz(MPE)

15 The Polar AM Herculis companion of type dm4 P orb = 186 min = 3.1 hours d = 85 ± 5 pc B = 14.5 MG T wd = K a) b) c) d) e) f) May 10, 2013 Photometry and Spectroscopy of Variable Stars with Small Telescopes VadimBurwitz(MPE)

16 Lightcurve: Polar I R V B U May 10, 2013 Photometry and Spectroscopy of Variable Stars with Small Telescopes VadimBurwitz(MPE)

17 Lightcurve: Polar RX J = RS Caelum V ~ 19 mag.

18 Lightcurve: Intermediate Polar RX J = UU Col V ~ 17.6

19 Accreting white dwarfs Types of accreting white dwarfs Magnetic and non-magnetic accretion White dwarfs at high accretion rates Supersoft X-ray Sources Novae in M31 May 10, 2013 Photometry and Spectroscopy of Variable Stars with Small Telescopes VadimBurwitz(MPE)

20 Observational definition of supersoft X-ray binaries Supersoft > 90% of intrinsic source photons in kevband below 0.5 kev X-ray luminous soft X-ray source f softx > f opt Binary evidence for binarity: e.g. orbital period, variability May 10, 2013 Photometry and Spectroscopy of Variable Stars with Small Telescopes VadimBurwitz(MPE)

21 Discovery of SSXBs with ROSAT May 10, 2013 Photometry and Spectroscopy of Variable Stars with Small Telescopes VadimBurwitz(MPE)

22 Nature of the binary components Primary: wd, ns, bh? observational evidence: energy distribution radius radial velocity curve mass function jets escape velocity white dwarf Secondary: observational evidence: none theoretically expected: spectral type A F (M 2 >M 1 ) or spectral type K M (M 2 < M 1 ) May 10, 2013 Photometry and Spectroscopy of Variable Stars with Small Telescopes VadimBurwitz(MPE)

23 SSXBs as accreting binaries m B = mag P orb = 1.04 days i = 25 deg m B = 16.2 mag P orb =0.76 days I ~ edge on RX J CAL 83 m B = 19 mag Sun P orb =10.6 hours I ~ edge on CAL 87 van Teeseling, Kube May 10, 2013 Photometry and Spectroscopy of Variable Stars with Small Telescopes VadimBurwitz(MPE)

24 RXJ : long term optical lightcurve MACHO Data Southwell et al May 10, 2013 Photometry and Spectroscopy of Variable Stars with Small Telescopes VadimBurwitz(MPE)

25 RXJ : long term optical lightcurve Burwitz et al May 10, 2013 Photometry and Spectroscopy of Variable Stars with Small Telescopes VadimBurwitz(MPE)

26 RXJ : X-ray and optical variability Reinsch et al May 10, 2013 Photometry and Spectroscopy of Variable Stars with Small Telescopes VadimBurwitz(MPE)

27 RXJ : X-ray and optical variability Reinsch et al May 10, 2013 Photometry and Spectroscopy of Variable Stars with Small Telescopes VadimBurwitz(MPE)

28 RXJ : X-ray and optical variability Reinsch et al May 10, 2013 Photometry and Spectroscopy of Variable Stars with Small Telescopes VadimBurwitz(MPE)

29 Discovery of extragalactic novae: monitoring of M31 So far 6 CBET or Atel entries May 10, 2013 Photometry and Spectroscopy of Variable Stars with Small Telescopes VadimBurwitz(MPE)

30 Summary Part I Variable Stars Offer many possibilities for astrophysical studies using small telescopes Accreting white dwarfs CVs are easily accessible to photometry the short orbital periods (several hours to days) yield lots of information in a short time Low Resolution Spectroscopy: Brighter objects can be observed nicely Detecting and Monitoring Novae in M31 or sim. through regular observation of same fields patience is eventually rewarded. May 10, 2013 Photometry and Spectroscopy of Variable Stars with Small Telescopes VadimBurwitz(MPE)

31 Physics Innovations Robotic Astronomical Telescope Explorer

32 Physics Innovations Robotic Astronomical Telescope Explorer

33 PIRATE site Observatori Astronomic de Mallorca (OAM) host observatory of SXR208 Longitude E 2 57' 06'' Latitude N 39 38' 38'' Altitude 203 m

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35 PIRATE milestones 2008 PIRATE prototype funded initially by a UK teaching initiative (OU & Leicester University) and OAM to explore feasibility of use in distance teaching remote students + remote telescope = perfect match? 2009 New robotic dome 2010 New telescope (17 inch reflector) 2011: New main imaging camera (4kx4k CCD) PIRATE is now semi-autonomous and used in main-stream OU teaching and research

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37 PIRATE in research Photometric monitoring of variable stars Transient search novae in M31 Gaia transient alert network facility Exoplanettransit candidate winnowing for SuperWASP and QES Serendipitous science

38 PIRATE published Faedi et al 2012, A&A, submitted (new planets WASP-54b, 56b, 57b) Haswellet al 2012, ApJ760, 70 (second HST visit of WASP-12) Faillace et al 2012, JBAA, in press (near-contact binary) Rodda et al 2012, JBAA, in press (chromospherically active binary) Bloom et al 2012, ApJ Letters,744, L17 (supernova SN2011fe) Holmes et al 2011, PASP 123,1177, (PIRATE commissioning) Lucas & Kolb 2011, JBAA 121, 265 (software architecture) Fossatiet al 2010 ApJL(HST visit of WASP-12) 8 ATelor CBET notes (M31 novae)

39 Searching for extrasolar planets: the transit method Hans Deeg

40 SuperWASP is the most successful exoplanet search project (80 confirmed planets) Identifies promising A candidates per year but many are false positives observed 80 A candidates since June 2011, to identify false positives Expensive high-resolution spectroscopy at large telescopes (OHP, ESO La Silla)

41 Contaminants Grazing eclipses of stellar binaries Blends: background eclipsing binaries BEBs Eclipsing brown dwarf binaries

42 SuperWASP: EB blend

43 HAT-P-20b top: PIRATE bottom: SuperWASP

44 TReS-2b TReS-3b XO-1b

45 Science 4 Jan 2013 issue

46 Earliest known measurement of supernova in M101 23/08/2011 vs 24/08/2011

47 23 August 2011: PIRATE captures supernova only 3 hrs after explosion Supernova SN2011fe (also known as PTF11kly) in M101 at 6.4 Mpc the closest type Ia supernova for 40 years

48 t hr 1 arcmin PIRATE/Clear A SN2011fe PIRATE measurement shows that exploding object s radius is smaller than 0.02 R It must be a white dwarf. Teff = 4000 K T eff = 7000 K Bloom et al, 2012, ApJ Letters 744, L17 (complements Nugent et al 2011, Nature 480, 344)

49 PIRATE in OU teaching Observer teams of 2-4 students in Skype contact control PIRATE from home Third-level module Astrophysics (S382) project At least 3 observing nights per student, over a period of 2 months (about 60 students) Outcome is a collaborative group report (10 students) with research-grade data on a periodic variable star Second-level module Practical Science (S288) 1 observing night per student (15 nights, 60 students) Measurement of star cluster properties

50 RS CVn system 1SWASPJ S Castor group results

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52 SWASP J , pre-helium WD al 2012 July/August 2012 data Faillace et

53 Follow us on on facebook Open University PIRATE Facility

54 : Overview - hardware PIRATE Mark 1: Celestron C m SCT SBIG STL-1001E (1k x 1k 24µ pixels) Paramount ME GEM ƒ/11 F.O.V 22 x 22 Plate scale: 1.21 pixel -1 PIRATE Mark 2: PlaneWave CDK m SBIG STX (4k x 4k 9µ pixels) ƒ/6.8 F.O.V 43 x 43 Plate scale: 0.64 pixel -1

55 : Overview - software

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57 PIRATE for SuperWASP False positive elimination in A candidates (Holmes, Busuttil, Bochinski, Kolb & Haswell) about 60 sources observed since June 2011

58 60cm PTST in Mallorca May 10, 2013 Photometry and Spectroscopy of Variable Stars with Small Telescopes VadimBurwitz(MPE)

59 60cm at MPE Garching Germany May 10, 2013 Photometry and Spectroscopy of Variable Stars with Small Telescopes VadimBurwitz(MPE)

60 Summary Part II: PIRATE Telescopes Robotic telescope for teaching and complementing large telescope projects PIRATE Open University 43 cm OAM Versatile small telescope Two new 60cm Telescope Projects PTST Hamburg University OAM, Mallorca, Spain MPE/MPA/TUM Telescope, Garching, Germany May 10, 2013 Photometry and Spectroscopy of Variable Stars with Small Telescopes VadimBurwitz(MPE)

61 DADOS Spectrograph: Motivation Develop a Spectrograph for use in a physics or astronomy lab course with following characteristics: Easy and Flexible to use: Eyepiece Webcam CCD Camera Digital Camera Selectable spectral resolution (i.e. different gratings) Selectable spectralrange Light and compact Built in possibility to guide May 10, 2013 Photometry and Spectroscopy of Variable Stars with Small Telescopes VadimBurwitz(MPE)

62 The resulting spectrograph May 10, 2013 Photometry and Spectroscopy of Variable Stars with Small Telescopes VadimBurwitz(MPE)

63 The optical paths May 10, 2013 Photometry and Spectroscopy of Variable Stars with Small Telescopes VadimBurwitz(MPE)

64 How are Spectra formed? Prism Rainbow Transmissiongrating Reflectiongrating May 10, 2013 Photometry and Spectroscopy of Variable Stars with Small Telescopes VadimBurwitz(MPE)

65 Study different kind of light sources/spectra - Classic incandescent lamp - Halogen lamp - LEDs continuum spectrum incandescent lamp : in front a - Dense / cool gas - Filter comparable to solar light (Fraunhofer lines) Zum Leuchten angeregtes Gas: - Energies saving lamps - Flourescent lamps - Neon lamps comparable to licht from planetay Nebulae absorption line spektrum emission line spektrum

66 Qualitative Analysis of Spectra with eyepiece and eye / Webcam rough classification

67 Spectra obtained with the 200line/mm Grating

68 Spectra obtained with the 900line/mm Grating May 10, 2013 Photometry and Spectroscopy of Variable Stars with Small Telescopes VadimBurwitz(MPE)

69 Quantitative Analysis of Spectra Using Cameras (CCD) and data analysis software very detailed Procyon Aldebaran H alpha May 10, 2013 Photometry and Spectroscopy of Variable Stars with Small Telescopes VadimBurwitz(MPE)

70 Analysingthe light Every day lamps Incandescent lamps continuum Energy saving/ Flourescent lamp Lines + continuum Neon lamps Lines LEDs continuum around LED color Laser single Lines Astronomical Objects: Sun Fraunhofer lines = Absorption lines Planets Absorption bands Comets Emission lines Stars similar to Sun Nebulae Emission lines May 10, 2013 Photometry and Spectroscopy of Variable Stars with Small Telescopes VadimBurwitz(MPE)

71 Sample Spectra Comparison of street lamp spectra with the City+Airport lamps of Palma de Mallorca Intensity Wavelength May 10, 2013 Photometry and Spectroscopy of Variable Stars with Small Telescopes VadimBurwitz(MPE)

72 A Wolf RayetStar Spectrum May 10, 2013 Photometry and Spectroscopy of Variable Stars with Small Telescopes VadimBurwitz(MPE)

73 Every day Spectra May 10, 2013 Photometry and Spectroscopy of Variable Stars with Small Telescopes VadimBurwitz(MPE)

74 Astronomical Spectra May 10, 2013 Photometry and Spectroscopy of Variable Stars with Small Telescopes VadimBurwitz(MPE)

75 Spectral Classification May 10, 2013 Photometry and Spectroscopy of Variable Stars with Small Telescopes VadimBurwitz(MPE)

76 Doppler Shifts in H-alpha line in βaurigae May 10, 2013 Photometry and Spectroscopy of Variable Stars with Small Telescopes VadimBurwitz(MPE)

77 BACHES first presentation ESO Messenger Sept , 63 Gerardo Avila, ESO Vadim Burwitz, MPE Carlos Guirao, ESO Jesus Rodriguez, ESO Raquel Shida, ESO Dietrich Baade, ESO Vadim Burwitz MPE Garching 77

78 BACHES first presentation ESO Messenger Sept , 63 Evolution of Hα and Hβ lines in the Be star ζ Tau (HD 37202) over 44 days Orbital period days Vadim Burwitz MPE Garching 78

79 BACHES first comercial Prototype by Baader Planetarium GmbH Vadim Burwitz MPE Garching 79

80 BACHES on a telescope Vadim Burwitz MPE Garching 80

81 BACHES Solar Spectrum with a Canon EOS 400D Vadim Burwitz MPE Garching 81

82 Hα BACHES Solar Spectrum mit Canon EOS 400D Na I Mg I Vadim Burwitz MPE Garching 82

83 Hα BACHES Solar Spectrum mit Canon EOS 400D Na I Mg I Vadim Burwitz MPE Garching 83

84 BACHES Solar Spectrum with a Canon EOS 400D Vadim Burwitz MPE Garching 84

85 Selectable BACHES or CCD Imager Vadim Burwitz MPE Garching