搜索
查看: 453|回復: 0

Observations of V420 Aur (HD 34921) needed to support spectroscopy

[複製鏈接]
發表於 2016-10-5 06:35:19 | 顯示全部樓層 |閱讀模式
[size=13.3333px]AAVSO Alert Notice 554

[size=13.3333px]October 3, 2016

[size=13.3333px]Observations of V420 Aur (HD 34921) needed to support spectroscopy


[size=13.3333px]Marcella Wijngaarden and Kelly Gourdji (graduate students at the
[size=13.3333px]University of Amsterdam/Anton Pannekoek Institute for Astronomy)
[size=13.3333px]have requested AAVSO observers' assistance in providing optical
[size=13.3333px]photometry in support of their high-resolution spectroscopy with
[size=13.3333px]the Mercator telescope + Hermes spectrograph in La Palma 2016
[size=13.3333px]October 7 through 17.

[size=13.3333px]They write: "[V420 Aur (HD 34921) is] the optical Be star that is
[size=13.3333px]part of a peculiar High Mass X-ray Binary...[that exhibits highly]
[size=13.3333px]complex and variable spectra...it is difficult to construct a
[size=13.3333px]physical model of this HMXB system. Though based on these
[size=13.3333px]observations, the system is thought to contain a B[e] star with a
[size=13.3333px]dense plasma region, an accretion disk around a neutron star, a
[size=13.3333px]shell and circumstellar regions of cold dust. It has been over a
[size=13.3333px]decade since the last spectra were taken, and, given the highly
[size=13.3333px]variable nature of this star, we expect new observations to yield
[size=13.3333px]new information that will contribute to a better understanding of
[size=13.3333px]this system."

[size=13.3333px]Observations in BVRI are requested beginning immediately and
[size=13.3333px]continuing through October 24. The PI's write: "Observations using
[size=13.3333px]other filters will be useful as well as long as there are multiple
[size=13.3333px]observations in these bands. In all cases, timeseries in a few
[size=13.3333px]bands (i.e. BVRI) are preferred over single/a few observations in
[size=13.3333px]the other bands as it is the variability on relatively short
[size=13.3333px]timescales that is most important. Unfiltered observations are in
[size=13.3333px]this case also useful but preferably only when they are available
[size=13.3333px]for multiple nights (in order to cross-match with other
[size=13.3333px]observations).

[size=13.3333px]"The target is bright so exposures should be long enough to reach
[size=13.3333px]good signal to noise in order to see the small variability
[size=13.3333px]amplitude but without saturating the target/comparison stars." With
[size=13.3333px]a range of V = 7.35 - 7.51, V420 Aur is a good candidate for PEP,
[size=13.3333px]DSLR, and CCD photometry. Its very small amplitude makes it a
[size=13.3333px]challenging target for visual observations.

[size=13.3333px]The PI's continue: "We will study the variability on several
[size=13.3333px]timescales, so observations starting from a few per night to high
[size=13.3333px]cadence timeseries are useful. Especially in the [October 7-17]
[size=13.3333px]period the higher rate the better.

[size=13.3333px]"Observations starting as soon as possible are ideal, for these the
[size=13.3333px]requirements are the same as above...We request the same
[size=13.3333px]observations until one week after the spectroscopic observing
[size=13.3333px]run...[so] that hopefully we have enough to phase fold the data."

[size=13.3333px]Coordinates (2000.0): R.A. 05 22 35.23  Dec. +37 40 33.6

[size=13.3333px]Charts with a comparison star sequence for V420 Oph may be created
[size=13.3333px]using the AAVSO Variable Star Plotter (VSP,[size=13.3333px]https://www.aavso.org/vsp[size=13.3333px]).

[size=13.3333px]Please submit observations to the AAVSO International Database
[size=13.3333px]using the name V420 OPH.

[size=13.3333px]This campaign is being followed on the AAVSO Observing Campaigns
[size=13.3333px]webpage ([size=13.3333px]https://www.aavso.org/observing-campaigns[size=13.3333px]). A thread has
[size=13.3333px]been created on the Campaigns and Observation Reports forum at
[size=13.3333px]([size=13.3333px]https://www.aavso.org/content/v420-aur-hd-34921-observing-campaign[size=13.3333px]).


[size=13.3333px]This AAVSO Alert Notice was compiled by Elizabeth O. Waagen.

[size=13.3333px]----------------------------------
[size=13.3333px]SUBMIT OBSERVATIONS TO THE AAVSO

[size=13.3333px]Information on submitting observations to the AAVSO may be found at:
[size=13.3333px]https://www.aavso.org/webobs

[size=13.3333px]ALERT NOTICE ARCHIVE AND SUBSCRIPTION INFORMATION

[size=13.3333px]An Alert Notice archive is available at the following URL:
[size=13.3333px]https://www.aavso.org/alert-notice-archive

[size=13.3333px]Subscribing and Unsubscribing may be done at the following URL:
[size=13.3333px]https://www.aavso.org/observation-notification#alertnotices

[size=13.3333px]-------------------------------------------------

您需要登錄後才可以回帖 登錄 | 申請討論區帳戶

本版積分規則

手機版|Archiver|香港天文學會  

GMT+8, 2019-9-20 14:07 , Processed in 0.033952 second(s), 10 queries , Redis On.

Powered by Discuz! X3.4

© 2001-2013 Design S!|平潭

快速回復 返回頂部 返回列表