AAVSO -- Proposal #463

Proposer	(38172) Ariovaldo Siqueira (ari.m.siqueira@icloud.com) obscode: SAMA
Assigned To	(3663) Dirk Terrell
Date Submitted	Nov. 25, 2023
Status	Declined
Priority	Normal
Proposal	I request time in one of the AAVSOnet Bright-Star Monitor telescopes to obtain photometric data of the NSV16610 (or sig Ori, HD37468, 000-BBJ-808) a Young Stellar Object, recorded at AID only twice. There follows some information on the target and its desired monitoring: ICRS coord. J2000: 05 38 44.7653828520 -02 36 00.283179888 Spectral type: O9.5V+B0.2V(n) Mag.: 3.79 [0.01] V Target visual dimension: pinpoint Desired FOV: adequate for photometric measurements, at the AAVSOnet’s team discretion Cadence: once a week, three images per observation per filter Initial project duration: 6 months or 26 nightly observations Filters: BVRI Exposure: I leave it to be decided by the AAVSOnet team, depending on the optics and camera to be chosen; it will probably be under 1 second, to avoid pixel saturation. Motivation: • By monitoring the selected target I will be collaborating with the HOYS initiative (Hunting Outbursting Young Stars), to which I have been invited by its coordinator, Dr. Dirk Froebrich (University of Kent, Dublin, Ireland), and contributing data to the AAVSO photometric database. The HOYS citizen science project works with amateur astronomers on long-term photometric monitoring of nearby young stellar clusters and star-forming regions visible from the Northern Hemisphere to find any occasional stellar outbursting or other interesting objects for detailed follow-up and for the study of star and planet formation processes. • I will attempt to establish the periodicity of sig Ori, if feasible. • I will be learning about the observation of an area harboring several young stellar objects. I intend to join the YSO Section of the AAVSO along with the development of this project.

Targets
Target	RA (H.HH)	Dec (D.DD)	Magnitude	Telescope	Observation Frequency	Expiration Date	Proprietary Term
NSV 16610	5.645768	-2.60008	3.5–4.0	—	—	—	No

Comments

(3663) Dirk Terrell — Dec. 7, 2023, 5:18 p.m.: There are grave concerns about the feasibility of doing this project. The amplitude is very small and there is significant crowding which is going to dilute the signal even further. Sebastian may have further to say on the matter.
(3000) Sebastián Otero — Dec. 7, 2023, 6:58 p.m.: Ari, the first thing to keep in mind is that even when SIMBAD classifies this one as YSO, that's based on a paper of YSOs in the sigma Ori cluster (not specifically on this object), but classifying such a high mass system as YSO is not actually appropriate. The two spectral types you mentioned are for the components of the AB binary which has a 0.25" separation and a 155 yr. period so if there is some kind of variation in this inner system, it won't be noticed in the short term.
I checked TESS data and variations only have an amplitude up to 0.007 mag. (with a possible 13.1 d. period). And contribution from 11" and 13" companions (9th and 7th mag.) might make things even worse.
I think that this is not a good target to observe from the ground, both in terms of its nature (not a YSO) and its extremely small amplitude.
I would select another target.
(38172) Ariovaldo Siqueira — Dec. 7, 2023, 7:20 p.m.: Thank you for your comments, Dirk.
I will try to provide preliminary images of the target, qualifying the gear used to obtain it. This might help to evaluate the feasibility of this project, along with any other comments that S. Otero might add.
(38172) Ariovaldo Siqueira — Dec. 7, 2023, 7:22 p.m.: Thank you for your comments, Sebastian.
I am awaiting Dr. Dirk Froebrich (University of Kent, D.Froebrich@kent.ac.uk), P. I. of the HOYS project, to comment, which I will share with you.
(38172) Ariovaldo Siqueira — Dec. 7, 2023, 9:29 p.m.: Hello, Dirk and Sebastian.
First of all, there was a mistake in my proposal: I should have referred to the sigma Ori field, not the sigma Ori star. In such a field, there are many objects of interest for the HOYS project or other studies aiming YSOs. It has been calculated that star formation in the cluster began only 3 million years ago.
Therefore, what I intend to target are young stars of the sigma Ori cluster with magnitudes from 10 to ~16-17.
Second, never mind the claim that I expect to establish the periodicity of any of the variable stars in this field, as YSOs have rotation periods between 1 and 14 days. So, my data alone will not suffice to establish periodicities among these stars.
Please, do not discard my proposal, but let me reformulate it in the next few days, less than a week, to make it meaningful and feasible.
Yours thankfully,
(3000) Sebastián Otero — Dec. 7, 2023, 10:10 p.m.: Sounds good. Always keep in mind crowding and nebulosity in this area. Large field of views will fail to measure faint targets due to blending of several stars. So select fields that might not be too crowded.
(38172) Ariovaldo Siqueira — Dec. 15, 2023, 9:53 p.m.: Hello,
Could the AAVSOnet just eliminate this proposal, #463?
Proposal #467 was submitted to replace this one.
Thank you.
(4726) Kenneth Menzies — Dec. 16, 2023, 10:55 p.m.: Declined and Replaced by P467.

Comments on this proposal are closed.