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ASASSN-17gk: Likely Galactic Nova (10.9 mag) in Centaurus

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SPK's picture
ASASSN-17gk: Likely Galactic Nova (10.9 mag) in Centaurus

ASASSN-17gk (N:)

RA 13:20:55.32, DEC -63:42:18.5 (J2000.0)

K. Z. Stanek et al.:
"ASAS-SN Discovery of A Likely Galactic Nova ASASSN-17gk on the Rise" (ATel #10387)

ASASSN-17gk 20170423.16 <174V ASN
ASASSN-17gk 20170425.08 133V ASN
ASASSN-17gk 20170428.11 116V ASN
ASASSN-17gk 20170504.19 12.05V ASN
ASASSN-17gk 20170517.28 109V ASN

A Gaia DR1 source (G= 18.767 mag) is located at RA 13:20:55.334, DEC -63:42:19.16 (J2000.0), 0.7" from the reported position of the transient.

Clear skies,

Quote from ATel #10387:
"Follow-up observations, especially multi-band photometry and spectroscopy, are strongly encouraged."


First spectrum attached (non instrument corrected).


CTX's picture
ASASSN-17gk Sequence

ASASSN-17gk now has a sequence

Ad Astra & Good Observing,

Tim Crawford, CTX, Sequence Team

Photometry uploaded.

After grabbing the confirmation spectra, I managed very quick V-band and B-band images before the cloud (and rain) hit Perth last night. I'm not convinced my tranformations are perfect, as the magnitude (V=8.8) came out at much brighter than PEX's visual observation not far from me last night. See the database for information. I couldn't get TA to work (I suspect it doesn't like ASASSN-17gk as the database reference) so relied on manual (ie, spreadsheet) transformaiton. I suspect that, together with noisey data, may be at play. For the mean time, I figure some photometry is better than none.

EDIT: I've tried replacing ASASSN-17gk with 000-BMH-424 in TA without success. The complaint is "no CREF available, possibly bad char reference, failed VSP API chart request, etc.".

EDIT 2: I've fixed my issues (error with reporting of instrumental values from Muniwin) and recomputed. 

Corrected transformed CCD measurements:

V = 10.70
B = 11.78 

Database updated accordingly.




weo's picture
ASASSN-17gk in AAVSO Alert Notice 578

AAVSO Alert Notice 578 announces and summarizes information on ASASSN-17gk, a galactic nova in Centaurus. Please see the Alert Notice for details and observing instructions.

Many thanks, and good observing,

Elizabeth Waagen, AAVSO HQ

TCB168's picture
Nova in Cent

I have tried to take a high resolution spectra of the Ha region of this nova. At mag V=11 at the time it is very dim for my setup. A low res spectrum is easy but I didn't have the low res spectrograph on the scope at the time.

I was able to identify the Ha emission and measure the expansion velocity at 1000km/s despite a low S/N with just 15 mins of exposure.




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