Optical TiO and VO band emission in two embedded protostars: IRAS 04369+2539 and IRAS 05451+0037

Abstract

Archival optical spectra from the Sloan Digital Sky Survey of two optically faint flat spectrum protostars, IRAS 04369+2539 and IRAS 05451+0037, show strong emission-line features including -- notably -- clear and broad emission across several molecular bands of TiO and VO. The molecular emission is indicative of dense, warm circumstellar gas and has been seen previously in only one object: the flat spectrum protostar IRAS 20496+4354 during a strong optical outburst (PTF 10nvg; Covey et al. 2011). The presence of broad molecular emission features in two additional objects having similar mid-infrared properties (but not known to be undergoing outbursts) could provide new insight into phases of rapid accretion / outflow at early stages of the protoplanetary disk. At present, the relevant geometry and the formation or heating mechanisms responsible for the observed TiO / VO cooling emission remain unexplained.

accepted to AJ

References in corpus (11)

• Stellar SEDs from 0.3-2.5 Microns: Tracing the Stellar Locus and Searching for Color Outliers in SDSS and 2MASS
• The SCUBA Legacy Catalogue: Continuum Objects Detected by SCUBA
• Atomic and Molecular Opacities for Brown Dwarf and Giant Planet Atmospheres
• The chemical history of molecules in circumstellar disks. II. Gas-phase species
• CO rovibrational emission as a probe of inner disk structure
• Spitzer IRS Spectra and Envelope Models of Class I Protostars in Taurus
• Formation of Organic Molecules and Water in Warm Disk Atmospheres
• Evidence for Early Circumstellar Disk Evolution in NGC 2068/71
• Detection of C3O in the low-mass protostar Elias 18
• A Low-Mass H2 Component to the AU Microscopii Circumstellar Disk
• CaII Infrared triplet line models in Classical T Tauri stars

Cited by in corpus (15)

• An Optical Spectroscopic Study of T Tauri Stars. I. Photospheric Properties
• ExoMol Molecular linelists -- XXXIII. The spectrum of Titanium Oxide
• Pure rotational spectra of TiO and TiO_2 in VY Canis Majoris
• Highly Variable Extinction and Accretion in the Jet-driving Class I Type Young Star PTF 10nvg (V2492 Cyg, IRAS 20496+4354)
• FRagmentation and Evolution of dense cores Judged by ALMA (FREJA). I (Overview). Inner $\sim$1000 au structures of prestellar/protostellar cores in Taurus
• B- and A-Type Stars in the Taurus-Auriga Star Forming Region
• First large scale Herbig-Haro jet driven by a proto-brown dwarf
• Very low-luminosity Class I/Flat outflow sources in sigma Orionis
• ALMA reveals a pseudo-disc in a proto-brown dwarf
• LkH$\alpha$ 225 (V1318 Cyg) South in Outburst
• HH 1158: The lowest luminosity externally irradiated Herbig-Haro jet
• Magellanic Cloud stars with TiO bands in emission: binary post-RGB/AGB stars or young stellar objects?
• Influence of the C/O ratio on titanium and vanadium oxides in protoplanetary disks
• A low-mass hub-filament with double centre revealed in NGC2071-North
• VVV-WIT-13: an eruptive young star with cool molecular features