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HD 306414 and IGR J11215-5952

ATel #470; Ignacio Negueruela (Alicante), David M. Smith (U. C. Santa Cruz), Sylvain Chaty (CEA/Saclay)
on 23 Apr 2005; 09:38 UT
Credential Certification: Ignacio Negueruela (ignacio@dfists.ua.es)

Subjects: Infra-Red, Optical, X-ray, A Comment, Binary, Transient

Referred to by ATel #: 766, 768, 773

We note that the B supergiant HD 306414 (Tycho coordinates RA: 11 21 46.807, Dec: -59 51 47.93) lies only 16" away from the nominal position for the new INTEGRAL transient IGR J11215-5952 (ATel #469).

From 2MASS and USNO-B1 archival data analyses, HD 306414 is the brightest optical object in the 3' error circle, though there are three brighter IR sources, namely 2MASS J11214129-5953035 (K=7.15, b=15.3), 2MASS J11220105-5950185 (K=6.10, b=12.8) and 2MASS J11220165-5952502 (K=8.05, b=19.2). For HD 306414, 2MASS lists J=8.55, H=8.34, K=8.19.

Accurate optical photometry for HD 306414 is provided by Klare & Neckel (1977, A&AS 27, 215), who quote V=9.98, (B-V)=0.59, (U-B)=-0.45. Drilling (1991, ApJS 76, 1033) measures UBV values fully consistent within the expected errors. Vijapurkar & Drilling (1993, ApJS 89, 293) derive a spectral type B1Ia for HD 306414. The reddening to HD 306414 is, hence, moderate E(B-V)=0.78. If the luminosity class is correct and the reddening law is standard (Av=2.42), the distance to the supergiant is around 8 kpc.

Obviously only a better position for IGR J11215-5952 can confirm or discard the association with HD 306414. However, taking into account the accuracy of previous INTEGRAL nominal positions and the nature of most of the new INTEGRAL sources (e.g., Lutovinov et al. astro-ph/0411550 or ATel #429), the identity is very likely