Science Page

07/01/210: Supernova confirmation,

Electronic Telegram No. 2345 Central Bureau for Astronomical Telegrams INTERNATIONAL ASTRONOMICAL UNION
CBAT Director: Daniel W. E. Green; Room 209; Dept. of Earth and Planetary
Sciences; Harvard University; 20 Oxford St.; Cambridge, MA 02138; U.S.A.
e-mail: cbat@iau.org; cbatiau@eps.harvard.edu URL http://www.cfa.harvard.edu/iau/cbat.html

SUPERNOVA 2010ew
M. Peoples, J. Newton, and T. Puckett report the discovery of an apparent supernova (mag 16.6) on unfiltered CCD images (limiting mag 18.5) taken with a 0.40-m reflector at Portal, AZ, U.S.A., on June 28.39 UT in the course of the Puckett Observatory Supernova Search. The new object, which was confirmed at mag 16.6 on images (limiting mag 19.8) taken by P. Mortfield and S. Cancelli on June 29.48 with a 0.40-m reflector at Sierra Remote Observatories in California, is located at R.A. = 18h37m11s.88, Decl. = +30o37'49".6 (equinox 2000.0), which is 4".6 west and 7".1 north of the center of the
presumed host galaxy. Nothing is visible at this position on images taken by Puckett on June 13 (limiting mag 19.1); however, T. Orff reports a precovery image (limiting magnitude of 18.5) taken by Puckett on June 20, which shows
2010ew at mag 17.1. NOTE: These 'Central Bureau Electronic Telegrams' are sometimes superseded by text appearing later in the printed IAU Circulars.

(C) Copyright 2010 CBAT 2010 July 1 (CBET 2345) Daniel W. E. Green

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05/21/10: Dear Observers,

The SRO science page has passed another milestone, the first publication using SRO data accepted for publication in a refereed journal:

The orbital and superhump periods of the deeply eclipsing dwarf nova SDSS J150240.98+333423.9 (2010)

by Shears, J., Campbell, T., Foote, J., Garrett, R., Hager, T., Julian, W. M., Kemp, J., Masi, G., Miller, I., Patterson, J., Richmond, M., Ringwald, F., Roberts, G., Ruiz, J., Sabo, R., & Stein, W.

This was a Center of Backyard Astrophysics campaign I participated in last summer, in which I got a week of unfiltered time-resolved photometry of a dwarf nova undergoing a superoutburst. This was a dwarf nova discovered in the Sloan Digital Sky Survey, and was found to be deeply eclipsing. We were able to see the tidally induced modulations in the disk, called superhumps, that appear during these superoutbursts. Superhumps are from the accretion disk becoming elliptical and sloshing around, like this: http://zimmer.csufresno.edu/~fringwal/superhumps.gif

The article was submitted to the Journal of the British Astronomical Association, because the lead author, Jeremy Shears, is from Cheshire. The article should appear in the journal sometime in the coming months, but a copy of the article is now available at the astro-ph preprint server, here.

Best, Fred

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03/16/10: Dear Observers,

My current grad student, Kenia Velasco, has just turned in her Masters thesis, the second to use data from Fresno State's station at SRO. The title is "Waves in an Accretion Disk: Negative Superhumps in V378 Pegasi." She discovered bending waves in the accretion disk of the cataclysmic variable V378 Pegasi. These are waves out of the plane of the disk: they're similar to the warps shown by some spiral galaxies, but it's much easier to study their dynamics since a spiral galaxy rotates in about 200 million years, whereas the orbital period of V378 Pegasi is 3.326 hours. Read the thesis, if you don't believe me. It's here: http://zimmer.csufresno.edu/~fringwal/thesis-Kenia.pdf

I am in the process of turning this into a paper in a refereed journal. I'll send a copy to the science page when it's accepted.

Last year's grad student, Randy Clark, wrote the first Masters thesis to use SRO data. The title was "A Search for Extrasolar Planets Using Echoes Produced by Flare Events." The idea is that there are known to be about a dozen stars that are apparently just like the Sun, but they have flares that strongly resemble magnetic solar flares, but they can have luminosities that are 10 million times greater than solar flares! The Sun can never have had one of these "superflares": it would have sterilized Earth. How do these apparently Sun-like stars have such luminous flares, then? The discovery of hot Jupiters may offer a solution. Jupiter is well known to have a powerful magnetic field: if a planet just like Jupiter were closer to the Sun than Mercury, its magnetic field would affect the magnetic field of the Sun. The thesis is here:

http://zimmer.csufresno.edu/~fringwal/thesis-Randy.pdf

I am hoping that I can get other students to continue this work, since as you can see, so far we have observed only one of these stars, S Fornacis.

Best, Fred

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July 16, 2009: Telegram regarding the newly discovered PN in Cygnus now designated PN G75.5+1.7

Electronic Telegram No. 1876
Central Bureau for Astronomical Telegrams
INTERNATIONAL ASTRONOMICAL UNION
M.S. 18, Smithsonian Astrophysical Observatory, Cambridge, MA 02138, U.S.A.
IAUSUBS@CFA.HARVARD.EDU or FAX 617-495-7231 (subscriptions)
CBAT@CFA.HARVARD.EDU (science)
URL http://www.cfa.harvard.edu/iau/cbat.html

PN G75.5+1.7

     Last July, D. M. Jurasevich, Mount Wilson Observatory, discovered and reported that H-alpha CCD images taken on 2007 June 19.22 and 2008 July 6.17 UT, using an Astro-Physics 160EDF apochromatic refractor (+ SBIG STL-11000M
CCD camera + 6-nm Tru-Balance H-alpha filter) reveal a near-spherical shell of gas, located within a faint H II region near NGC 6888, that was apparently not noticed (or published) previously due to the density of stars and gas in that area of Cygnus. This shell appears as a slightly elongated ellipse with its major axis at p.a. 5 deg and having an apparent size of
260" x 235"; its center is located at R.A. = 20h15m22s.2, Decl. = +38d02'58" (equinox 2000.0); Jurasevich has posted photographs and other information regarding this nebula at website URL http://tinyurl.com/ku4ppy.

     The nebula was independently noted and reported by K. B. Quattrocchi (Clovis, CA, U.S.A.) and M. Helm (Fresno, CA, U.S.A.), who originally found it on eight separate 10-min images taken on 2008 July 17.75 with a 40.6-cm f/3.75 astrograph (+ FLI Microline 16803 CCD camera + H-alpha filter) located at the Sierra Remote Observatories in the Sierra Nevada Mountains, providing the position end figures of the nebula as 21s.5, 43"; they have posted photographs and other information on this nebula at website URL http://www.lostvalleyobservatory.com/page29crescentbubblenb/.

     A. Acker, Observatoire Astronomique Strasbourg, notes that the "INT Photometric H-alpha Survey of the Northern Galactic Plane" (IPHAS; cf. Gonzalez-Solares et al. 2008, ASP Conf. Ser. 394, 197; Gonzalez-Solares et al. 2008, MNRAS 388, 89) lists an object a couple of degrees away at R.A. = 20h15m22s.2, Decl. = +40d34'44".8.

     L. Kohoutek, University of Hamburg, writes that he can see PN G75.5+1.7 on both red and blue "transparencies" of the second Palomar Sky Survey (but not on the first POSS photographs), noting that the nebula is extremely faint there (only a trace), but having the same size as on the current images. Also, the blue star in the center is of similar brightness at all
epochs; this does not support a nova nebula, as the nebula has not changed in about sixteen years. Spectroscopy is encouraged, though this will be difficult because of its faintness.

NOTE: These 'Central Bureau Electronic Telegrams' are sometimes superseded by text appearing later in the printed IAU Circulars. (C) Copyright 2009 CBAT
2009 July 16                     (CBET 1876)              Daniel W. E. Green

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07/07/09:

One of the great Messier objects is now sporting a new star. I was able to grab an image yesterday (UT) using the 16" f/8.9. This is a combo of several 60second exposures with a bright moon at a 25 degree altitude. http://www.backyardastronomer.com/SN/m66-sn2009hd.jpg

for comparison, you can see on image from Dec 2007. http://www.backyardastronomer.com/ccd-images/m66-test1.jpg

thanks for looking. ...paul.

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Tuesday 6/30/2009 4:54 PM

Most of you know I was at KSC to see the LCROSS launch, http://www.backyardastronomer.com/lcross/lcross1.jpg but on sunday night (monday UT), was able to image the spacecraft using SRO Obs3. I'm doing astrometry of the data to help refine the spacecraft orbit/trajectory. The spacecraft was around mag 16.5 and moving. Here's the animation taken over 15min. I've got about an hour worth of data. One of the mission folks said it was 400,000km away at the time. http://www.backyardastronomer.com/lcross/LCROSS-20090629-anim2.gif

and its now on NASA's site for the mission. http://lcross.arc.nasa.gov/ cheers, ...paul.

Also seen in a Science@NASA article:
http://heliophysics.org/headlines/y2009/4review_lcross1.htm

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Dear Observers,

SRO now has spectroscopic capability. I had an empty slot in my filter wheel, so I put a transverse grating from a Rainbow Optics Star Spectrograph into it.

Doing this was easy. The grating is mounted in a holder for
a 1.25-inch filter, so all I had to do was to get an adaptor made so that I could fit a 1.25-inch filter into a slot for a 50-mm filter. I aligned the grating's transmission axis east-to-west, so the spectra would be dispersed perpendicular to the CCD's columns, and so would be easy to extract. (If I had an instrument rotator, this would be even easier, of course.)

I hesitate to call this a "spectrograph," since there is no slit. It therefore works similarly to how an objective prism works. When one takes a picture of something, one gets a picture of it, and to the side of this image is the spectrum.

Here's an example 0.1-s dark-subtracted image of Vega, taken though this grating:

http://zimmer.csufresno.edu/~fringwal/spectrum-vega-01s.jpg

Here's a spectrum intensity plot, which I extracted from
this image with AIP4WIN:

http://zimmer.csufresno.edu/~fringwal/spectrum-vega-01s-plot.jpg

I didn't do a flux calibration, and calibrated the wavelength scale only with night-sky lines, but you can clearly see the H-alpha line at 6563 Angstroms, the H-beta line at 4861 A, H-gamma at 4340 A, etc. The absorption features at longer wavelengths than H alpha are atmospheric bands, mostly of O2.

This spectrum has a dispersion of 7.2 Angstroms/channel, and therefore a resolution of about 16 Angstroms, or 730 km/s at H alpha. This is a low-resolution spectrum, but it'll be fine for bright novae: these have expanding shells of gas with Doppler-broadened lines that are thousands of km/s wide.

The wavelength coverage covers all of the visible range, from 3500 to 8600 Angstroms. As you may know, the unaided eye can see from about 4000 to 7500 Angstroms.

What I need now is for a bright nova to go off. Greg and I published two papers on watching novae going through their eruptions, but getting spectra with this setup will be a whole lot easier than with the SBIG spectrograph we used.

Best, Fred Ringwald

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03/14/09:

I used the FSQ/STL combo on thursday night to catch 2 comets in one, Comet Lulin [bottom] & Schwassmann-Wachmann [top]. (Paul Mortfield).

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02/20/09:

Here's a stack of 50x2min unguided (though Paramount was tracking the comet) using the FSQ/STL11K Maxim SDMask did the combine which perfectly removed the star trails. (Paul Mortfield).

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02/04/09: I shot this one [comet Lulin] with the FSQ/STL and it clearly shows the tail disconnect that's noticed by others on Spaceweather.com. ...paul

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01/14/09:

This project started in 2004 to track Barnard's Star; a special star which is known to have the highest proper motion of 10 arcseconds per year. The same telescope was used for all the images, though it has resided in 3 different places and two countries. The telescope started in Cupertino, California, then was relocated to Toronto, Canada and now located at Sierra Remote Observatories in California. This effort will continue with a new image taken once a year.

...paul.

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01/14/09:

This comet is getting interesting as it brightens, though the moon is now getting in the way. Shot last Thursday morning, Comet Lulin was shot in twilight, 5x2min unguided, 1/2 degree wide field with the 16". You can see the faint ion tail to the right. Interesting anti-tail towards the sun at left. Had to wait until it got 20 degrees in Alt. It is coming up right thru one of the tall trees to the east, so was causing some interesting effects thru the branches.

...paul.

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12/21/08:

I've posted nine color images you haven't seen before near the top of my own SRO page. Click on the image to follow the link.

...Fred Ringwald Ph.D.

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12/21/08:

...Time-resolved photometry of a cataclysmic variable binary star system, analyzed by another one of my students, Jonathan Roveto. Jonathan discovered tidal waves, also called permanent superhumps, sloshing around in the accretion disk, from which most of the light from the system comes. Up close, the waves probably look something like this: http://zimmer.csufresno.edu/~fringwal/superhumps.gif What convinced me that they're permanent superhumps is that they make a distinctive sawtooth pattern in the light curve, which has been there every night we've observed it.

...Fred Ringwald Ph.D.

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11/25/08:

Just thought I'd share some fun stuff going on up in the sky besides drifting toolbags. You all know about Tim Puckett's supernova patrol efforts, well Toronto amateur Eric Briggs made this recent discovery scanning images taken by Jack Newton as part of Tim's patrol program. I know Eric from club meetings up here, and this is his 2nd or 3rd find as part of the Puckett program. I thought I'd grab an image for him from SRO, since the skies up here may not clear until spring ;-) 5x2min unguided on the Wayback machine. http://www.backyardastronomer.com/SN/2008HJ-4b.jpg cheers

...Paul Mortfield.

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10/24/07:

Thought you'd enjoy seeing how faint these things really are. (Paul Mortfield).

100% - ~600K each http://www.backyardastronomer.com/asteroids/2008UY-anim1.gif

http://www.backyardastronomer.com/asteroids/2008UZ-anim1.gif

150% - 1.3M each http://www.backyardastronomer.com/asteroids/2008UY-anim2.gif

http://www.backyardastronomer.com/asteroids/2008UZ-anim2.gif

10/22/08: The SRO team has two new targets traveling around the sky.

Asteroids:
K08U00Y
K08U00Z

These are the temporary designations. Over the next 2yrs I'll be doing astrometry on them when they're up in the sky to help refine the orbit and hopefully get them officially numbered. Before AIC I'll have more data to be able to publish a better ephemeris incase anyone wants to try their hand at tracking down mag 20 asteroids. Thanks to all of you for making all this fun possible. cheers ...paul.

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Summer 2008:

Undesignated Bubble Nebula in Cygnus. Follow the story as it unfolds here about the co-discovery of a new bubble-like nebula that has not yet been catalogued. Additional info can be found here.

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March 3, 2008:

How far can you see with your telescope; an object with a redshift of 2.15. Thanks to Paul Mortfield for pointing out that there are a number of quasars behind NGC 3628.   The circle outlines the more distant quasar in the FOV. It has a redshift of 2.15. Others can be found here. Thanks to Fred Ringwald for providing interesting details as to "how far away" a redshift of 2.15 actually is. Fred's comments are as follows, "I just did the calculation, and I find that a redshift of z = 2.15 corresponds to seeing the object the way it was 10.6 billion years ago, which was during the first 3.1 billion years of the age of the Universe. This corresponds to a distance of 18.1 billion light-years. Notice that at such great distances, a light-travel time of 10.6 billion years doesn't imply a distance of 10.6 billion light-years, because the Universe has expanded significantly since the light left the quasar. There's also the non-zero cosmological constant to deal with. A nice primer for how to do calculations like this is here." Thanks Paul, thanks Fred for pointing out some interesting science in this image.