Continuing ARAS Group spectroscopic monitoring of RS Oph: appearance of high ionization lines
ATel #14881; S. N. Shore (Univ. of Pisa), F. Teyssier, O. Thizy (ARAS Group)
on 28 Aug 2021; 12:30 UT
Credential Certification: S. N. Shore (shore@df.unipi.it)
This is an update on the continuing spectroscopic monitoring of RS Oph by the ARAS group medium resolution (resolution above 9000, covering around 3900 to 8900A). Here we report only recent results from the echelle spectra. A large number of lower resolution, from about 200 to 1500, are also being accumulated (ATel#14868 and cited previous). The details of instruments and telescope apertures are provided on the website
(https://aras-database.github.io/database/rsoph.html).
For comparison, see
https://ui.adsabs.harvard.edu/abs/2008ASPC..401.....E/abstract
for an overview of the 2006 outburst.
All absorption has now vanished around Aug 25.0 from the Balmer profiles, the narrow wind P Cyg absorption at -36 km/s now shows weak, narrow emission on Halpha. The Halpha profile also shows a weak, extended wing to \vrad| ~ 3000 km/s with the maximum |vrad| ~ 2000 km/s at about twice the continuum level.; the line profile is steeper on the blue side.
He II 4686, 5411 are both present, HWZI ~ 1000 km/s and symmetric profiles. This contrasts with the He I profiles, especially 6678, that show an emission peak at +230 km/s; this is also present on the Balmer lines, O I 7774, 8446, and is different from the [N II] 5755 peak (-37 km/s). This peak is not present on either optical He II profile or N III 4636A, which is now stronger than He II 4686.
[Fe VI] 5276 shows a narrow feature, like [N II] and at -44 km/s, as does [Fe VII] 6087; the latter also appears to show a broader feature with maximum |vrad| ~ 640 km/s (HWZI) . The narrow component may have been present as early as Aug. 17. [Fe VII] 5720 may also show a weak narrow component after Aug. 25. If due to photoionization, it indicates flux at or above about 0.1 KeV so there may already be a strong soft source that is simply too absorbed by the still mainly neutral wind to be directly detectable. [Fe VI] 5276 may also have been present earlier but was more likely Fe II 5275. [Ar III] 7135 is likely present as a very weak, similarly narrow feature as early as Aug. 17.
ARAS Spectral Database
