an optical dip is underway in KIC 8462852 (Boyajian's Star

Exoplanet occultation, asteroid occultation,
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PTS
夸克星
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註冊時間: 週日 28 10月, 2007 08:50
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an optical dip is underway in KIC 8462852 (Boyajian's Star

文章 PTS » 週四 25 5月, 2017 05:55

AAVSO Alert Notice 579
May 24, 2017: T. Boyajian (Louisiana State University) et al. reported in ATel #10405 that an optical dip is underway in KIC 8462852 (Boyajian's Star, Tabby's Star) beginning on 2017 May 18 UT. Tentative signs of small dips had been seen beginning April 24, and enhanced monitoring had begun at once at Fairborn Observatory (Tennessee State University). Photometry and spectroscopy from there on May 18 and 19 UT showed a dip underway. Cousins V photometry showed a drop of 0.02 magnitude, the largest dip (and the first clear one) seen in more than a year of monitoring.

AAVSO observer Bruce Gary (GBL, Hereford, AZ) carried out V photometry which showed a fading from 11.906 V +/- 0.004 to 11.9244 V +/- 0.0033 between UT 2017 May 14 and May 19, a drop of 1.7%.

Swift/UVOT observations obtained May 18 15:19 did not show a statistically significant drop in v, but Gary's photometry is given more weight. r'-band observations from Las Cumbres Observatory obtained 2017 May 17 to May 19 showed a 2% dip.

I. Steele (Liverpool JMU) et al. report that spectra taken on 2017 May 20 with the 2.0 meter Liverpool Telescope, La Palma, showed no differences in the source compared to a reference spectrum taken 2016 July 4 when the system was not undergoing a dip (ATel #10406).

Dips typically last for a few days, and larger dips can last over a week. It is not clear that this dip is over.

Precision time-series V photometry is urgently requested from AAVSO observers, although all photometry is welcome. Dr. Boris Gaensicke (University of Warwick) has requested intense multi-color monitoring. Ongoing multiwavelength monitoring is being carried out at several sites. Swift observations will continue through June 9.

Dr. Dennis Conti, AAVSO Exoplanet Section chair, recommends the following procedure: "Start your observation when you can after twilight and continue taking images at an exposure that won't saturate your CCD camera (considering that it will brighten as it rises and dims as it falls from your local meridian). Use whatever filter [V is preferred] and exposure time you that gives the best SNR. If you can, do this for the next few days. After you have made a night's worth of observations (go for however long is convenient for you), create a light curve in AstroImageJ and forward it to dennis@astrodennis.com. Be sure to keep your original calibration and image files."

KIC 8462852 is 11.88 V at maximum (out of dip). It was the subject of AAVSO Alert Notices 532 and 542. Also, more information about it may be found in a 2016 paper by Boyajian et al. (2016MNRAS.457.3988B), available as a preprint at: http://arxiv.org/abs/1509.03622. General information about KIC 8462852 may be found at: http://www.wherestheflux.com/.

Coordinates (J2000): RA 20 06 15.46 , Dec +44 27 24.8

Finder charts with a comparison star sequence for KIC 8462852 may be created using the AAVSO Variable Star Plotter (VSP).

If observations are submitted to the AAVSO International Database, the name KIC 8462852 should be used.

For information on how to observe exoplanets and/or use AstroImageJ, please see the AAVSO Exoplanet Section page (https://www.aavso.org/exoplanet-section).

This AAVSO Alert Notice was compiled by Elizabeth O. Waagen.

-----------------------------------
SUBMIT OBSERVATIONS TO THE AAVSO

Information on submitting observations to the AAVSO may be found at:
https://www.aavso.org/webobs

ALERT NOTICE ARCHIVE AND SUBSCRIPTION INFORMATION

An Alert Notice archive is available at the following URL:
https://www.aavso.org/alert-notice-archive

Subscribing and Unsubscribing may be done at the following URL:
https://www.aavso.org/observation-notif ... ertnotices

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cytangjoseph
星際雲
文章: 23
註冊時間: 週一 10 8月, 2009 15:59

Re: an optical dip is underway in KIC 8462852 (Boyajian's Star

文章 cytangjoseph » 週一 29 5月, 2017 02:58

Can you share some basics of how to use AstroImageJ? eg, in smoothing, deconvolution, stacking?

thanks

PTS
夸克星
文章: 5768
註冊時間: 週日 28 10月, 2007 08:50
來自: HK

Re: an optical dip is underway in KIC 8462852 (Boyajian's Star

文章 PTS » 週四 01 6月, 2017 16:48

cytangjoseph 寫:
週一 29 5月, 2017 02:58
Can you share some basics of how to use AstroImageJ? eg, in smoothing, deconvolution, stacking?

thanks
I have no experience with this software. You can download a users' guide here:
http://www.astro.louisville.edu/softwar ... _Guide.pdf

pts

cytangjoseph
星際雲
文章: 23
註冊時間: 週一 10 8月, 2009 15:59

Re: an optical dip is underway in KIC 8462852 (Boyajian's Star

文章 cytangjoseph » 週六 03 6月, 2017 12:52

thanks PTS!!

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